LiM'fl'ii?*?

1^1 i©Mi<3^

n^ "^ajAiNajwv^

^.{/OJIIVO JO"^ ^<!/0JllVJJO>^

^OFCAlIFOff^lk, .^.OFCALIF0%

.\WEUNIVERS/A
{§ — "^

^>;lOSANCflfj>

■^/V83AIN(]-3WV^ '^^'^AHVHflln^^^' %AaV83n-^V^^ <rjl30NVSOl^'^ "^AaJAlNrtJWV"

•v^WlilBHAKYQ^

jo^ ^^m\mi^

^OFf

% ^lOSANCU£r>

% A>lOSANCFlfj>.

n2 ^.

V<^ ^/Sa3AINI13^

^•

^;OFCAllF0ff^

"^^OAttvaaii-i'^

,NlOSANCElfj>

^^Aa3AiNn]UV

^^^l•llBRARY■Gr -s>^tLIBRARYac

''AIIFO/?^ ^OF-CAllFOff^

aWEUNIVERS//,

5;>

//X A^lOSANCElfjVx

%a3AiNn-3WV^

^lOSANCElfj-^

/.ya]AiNft-3WV

AvMum .^

Off

..\v

^WE-l!N'I\Tf?T//.

\\\\ i'\'ivri?v//

in<^Avr.nrr,

., nFfAiir-'

^nM-LIBRARYOc,

^^OJIWDJO^

'^^FTAIIFOff^

'^''^

A\UUNIVER% ^lOSANGEiai,

^J:?133NVS0# ^/ia3AlNn-3VkV>

\\\E UNIVER^//.

\NCEl£r.>

]V3.jo>> ^.aOJIlVJJO^ ^XilJONVSOl^ %a3AINn3WV

s ^^=^1 I

aiFO/?^ ^OFCAllFOff^

AME UNIVERS/A A>:lOSANCElfj>

>^;OFCAIIFO%

<rii]3Nvsoi^ "^/jaaAiNdiV^^ -^oxn^mm'^ '^oxmrni"^

Wms/A, vvlOSANCElfx>

-s^lLIBRARY^/;^

-v;^llIBRARYac.

%a3AlN(l-3WV^ ^«!/0JnV3JO^ ^//OJIWD-JO"^

AWEUNIVERy//^

- _ ^ o

v^lOSANCElff
o

"^aaAiNn-avV'

\[\m//i

^^/smm-^^

^OF'CAllFO/P/j^

^OF"CAIIFO%

OS i\ />^ A S

"^(^Anvaaiiii^

^^AHvaaiH^

^\\E•UNIVERy//,

^>^:lOSANCElfj>

%iGAiNn]y^^

^ARYOc

1IF0%

^:^UIBRARYa<v

AMEUNIVER5/A

^lOSANCElfXA

^OF-CALIF0%

'<rii33|jvsoi'^'^ "^aaAiNOiWV^

,\WEUNIVER%

^lOSANCElfj^

aaiii^

.^UIBRARYQc. A^lilBRARYOc

^.KOjnvDio^ ^<!/ojnv3Jo^

^OFCAllFO/?^ ^OF-CALIFO/?^

'^OAyvaaiH^

%13QNVS0\^ %a3AiNnmv ^^(^AHViiaiH^ >&AavaaiHV^^

IIVERS//)

vj^lOSANCElfjv
o

%a3AINn-3WV>

-^s^lllBRARYO^, ^UIBRARYQ^

^^tfOJIlVDJO^ ^.tfOJITYDJO^

%a3AiN.aaft'^

"^(^Aavaani^

"^(?AyvHani^

^WEUNIVER%.

<rjl30NVSO)^

IIVER% ^lOSANCElfj^ ^OFCAIIFO/?^^ ^OFCAllFOff^ ^^WE UNIVERS/^

v^lOSANCElfj>

%a3AiNn3y\v

vi^lOSANCELfj-^

^J:?i3DNvsm^^ %a3AiNn-3WV'

[RARYQc^

ALIFOff></.

-^lllBRARYGr

%ojnv3jo^

.A.OFCAllFOffi/.

^Wt UNIVERS/A.

^iTiUDNVSOl^

%a3AINn3V^^

, \WE UNIVER5/A vvlOSANCElfT^,

-^lllBRARYQc. -s^illBRARYQc

.<.OF-CAlIF0/?;<> ,^,OFCAIIFO%

THE ANDES OF SOUTHERN

PERU

GEOGRAPHICAL RECONNAISSANCE ALONG THE
SEVENTY-THIRD MERIDIAN

ISAIAH BOWMAN

Director of the American Geographical Society

PUBLISHED FOR

THE AMERICAN GEOGRAPHICAL SOCIETY

OF NEW YORK

BY
HENRY HOLT AND COMPANY

«.-^K /^^ 1916

K Q

30944

COPTUIOHT, 1916
BT

HENRY HOLT AND COMPANY

EUS'T

TM« Ou<NN « aOOIN 00. PRUt
RAHWAV. H, 4,

'Njr

TO
C. G. B.

PREFACE

The geographic work of the Yale Peruvian Expedition of 1911
was essentially a reconnaissance of the Peruvian Andes along the
73rd meridian. The route led from the tropical plains of the lower
Urubamba southward over lofty snow-covered passes to the desert
coast at Camana. The strong climatic and topographic contrasts
and the varied human life which the region contains are of geo-
graphic interest chiefly because they present so many and such
clear cases of environmental control within short distances.
Though we speak of "isolated" mountain communities in the
Andes, it is only in a relative sense. The extreme isolation felt
in some of the world's great deserts is here unknown. It is there-
fore all the more remarkable when we come upon differences of
^ customs and character in Peru to find them strongly developed in
5^ spite of the small distances that separate unlike groups of people.
^* My division of the Expedition undertook to make a contour map

>^ of the two-hundred-mile stretch of mountain country between
^ Abancay and the Pacific coast, and a great deal of detailed geo-
^1 graphic and physiographic work had to be sacrificed to insure the
completion of the survey. Camp sites, forage, water, and, above
?^all, strong beasts for the topographer's difficult and excessively
^ lofty stations brought daily problems that were always serious
."^ and sometimes critical. I was so deeply interested in the progress
of the topographic map that whenever it came to a choice of plans
r\ the map and not the geography was first considered. The effect
upon my work was to distribute it with little regard to the de-
mands of the problems, but I cannot regret this in view of the
great value of the maps. Mr. Kai Hendriksen did splendid work
in putting through two hundred miles of plane-tabling in two
months under conditions of extreme difficulty. Many of his tri-
angulation stations ranged in elevation from 14,000 to nearly

viii PREFACE

18,000 feet, and the cold and storms— especially the hailstorms of

mid-afternoon — were at times most severe.

It is also a pleasure to say that Mr. Paul Baxter Lanius, my
assistant on the lower Urubamba journey, rendered an invaluable
serWce in securing continuous weather records at Yavero and else-
where, and in getting food and men to the river party at a critical
time. Dr. W. Gr. Erving, surgeon of the Expedition, accompanied
me on a canoe journey through the lower gorge of the Urubamba
between Rosalina and the mouth of the Timpia, and again by pack
train from Santa Ana to Cptahuasi. For a time he assisted the
topographer. It is due to his prompt surgical assistance to vari-
ous members of the party that the field work was uninterrupted.
He was especially useful when two of our river Indians from
Pongo de Mainique were accidentally shot. I have since been in-
formed by their patron that they were at work within a few
months.

It is difficult to express the gratitude I feel toward Professor
Hiram Bingham, Director of the Expedition, first for the execu-
tive care he displayed in the organization of the expedition's
plans, which left the various members largely care-free, and sec-
ond, for generously supplying the time of various assistants in the
preparation of results. I have enjoyed so many facilities for the
completion of the work that at least a year's time has been saved
thereby. Professor Bingham's enthusiasm for pioneer field work
was in the highest degree stimulating to every member of the
party. Furthermore, it led to a determination to complete at all
hazards the original plans.

Finally, T wish gi-atcrnlly to ackiiowlodgo the expert assistance
of Miss Ciladys M. Wrigley, of the editorial staff of the American
Geographical Society, who prepared the climatic tables, many of
the miscellaneous data related thereto, and all of the curves in
Chapter X. Miss Wrigley also assisted in the revision of Chap-
ters TX and X and in the correction of the proof. TTor eager and
in the highost dogreo fnilhfnl assistance in these tasks bespeaks
n frno soiontific spirit.

IsATATi Bowman.

SPECIAL ACKNOWLEDGMENTS FOR ILLUSTRATIONS

Fig. 28. Photograph by H. L. Tucker, Engineer, Yale Peruvian Expedi-
tion of 1911.

Fig. 43. Photograpli by H. L. Tucker.

Fig, 44. Photograpli by Professor Hiram Ijinghani.

Figs. 136, 139, 140. Data for^ hachured sketch maps, chiefly fi'ora topo-
graphic] sheets by A, H. Bumstead, Topographer to Professor Bingham's
Peruvian Expeditions of 1912 and 1914.

CONTENTS

PART I

HUMAN GEOGRAPHY

CHAPTEK PAGE

I. The Regions of Peru 1

II. The Rapids and Canyons op the Urubamba . . . . 8

III. The Rubber Forests . . 22

(XZ-^ The Forest Indians 36

V. The Country of the Shepherds 46

VI. The Border Valleys of the Eastern Andes .... 68
(yilTj) The Geographio Basis of Revolutions and of Human

Character in the Peruvian Andes 88

VIII. The Coastal Desert 110

IX. Climatology of the Peruvian Andes 121

X. Meteorological Records from the Peruvian Andes . . 157

XI.
XII.

XIII.

XIV.

XV.

XVI.

PART II

PHYSIOGRAPHY OF THE PERUVIAN ANDES

The Peruvian Landscape 183

The Western Andes: The Maritime Cordillera or Cor-

dillera Occidental

The Eastern Andes: The Cordillera Vilcapampa

The Coastal Terraces

Physiographic and Geologic Development .
Glacial Features

199
204
225
233
274

Appendix A. Survey Methods Employed in the Construction of

the Seven Accompanying Topographic Sheets . 315

Appendix B. Fossil Determinations 321

Appendix C. Key to Place Names 324

Index 327

TOPOGRAPHIC SHEETS
Camana Quadrangle 114

Aplao

Coropuna

Cotahuasi

La Cumbi-e

AntabamVa

Lambram't

120

188
192
202
282
304

PART 1
HUMAN GEOGRAPHY

CHAPTER I

THE REGIONS OF PERU

Let four Peruvians begin this book by telling what manner of
country they live in. Their ideas are provincial and they have a
fondness for exaggerated description: but, for all that, they will
reveal much that is true because they will at least reveal them-
selves. Their opinions reflect both the spirit of the toiler on the
land and the outlook of the merchant in the town in relation to
geography and national problems. Their names do not matter;
let them stand for the four human regions of Peru, for they are
in many respects typical men.

The Fokest Dweller

One of them I met at a rubber station on the lower Urubamba
River.^ He helped secure my canoe, escorted me hospitably to his
hut, set food and drink before me, and talked of the tropical forest,
the rubber business, the Indians, the rivers, and the trails. In his
opinion Peru was a land of great forest resources. Moreover,
the fertile plains along the river margins might become the sites
of rich plantations. The rivers had many fish and his garden
needed only a little cultivation to produce an abundance of food.
Fruit trees grew on every hand. He had recently married the
daughter of an Indian chief.

Formerly he had been a missionary at a rubber station on the
Madre de Dios, where the life was hard and narrow, and he doubted
if there were any real converts. Himself the son of an English-
man and a Chilean woman, he found, so he said, that a mission-
ary's life in the rubber forest was intolerable for more than a few

* For all locations mentioned see maps accompanying the text or Appendix C.

2 THE ANDES OF SOUTHERN PERU

years. Yet he had no fault to find with the religious system of
which he had once formed a part; in fact he had still a certain
curious mixed loyalty to it. Before I left he gave me a photo-
graph of himself and said with little pride and more sadness that
perhaps I would remember him as a man that had done some good
in the world along with much that might have been better.

We shall understand our interpreter better if we know who
his associates were. He lived with a Frenchman who had spent
several years in Africa as a soldier in the ' ' Foreign Legion. ' ' If
you do not know what that means, you have yet all the pleasure
of an interesting discovery. The Frenchman had reached the sta-
tion the year before quite destitute and clad only in a shirt and
a pair of trousers. A day's journey north lived a young half-
breed — son of a drunken father and a Machiganga woman, who
cheated me so badly when I engaged Indian paddlers that I should
almost have preferred that he had robbed me. Yet in a sense he
had my life in his hands and I submitted. A German and a native
Peruvian ran a rubber station on a tributary two days' journey
from the first. It will be observed that the company was mixed.
They were all Peruvians, but of a sort not found in such relative
abundance elsewhere. The defeated and the outcast, as well as
the pioneer, go down eventually to the hot forested lands where
men are forgotten.

While he saw gold in every square mile of his forested region,
my clerical friend saw misery also. The brutal treatment of the
Indians by the whites of the Madre de Dios country he could speak
of only as a man reviving a painful memory. The Indians at the
station loved him devotedly. There was only justice and kind-
ness in all his dealings. Because he had large interests to look
after, he know all the members of the tribe, and his word was law
in no hackneyed sense. A kindlier man never lived in the rubber
forest. His influence as a high-souled man of business was vastly
greater tlian as a missionary in this frontier society. He could
daily illustrate by practical example what he had formerly been
able only to proaoh.

He thought the lifo of tlio Peruvian cities debasing. The

Fig. 1.

Fig.

Fig. 1 — Tropical vegetation, clearing on the river bank and rubber station at
Pongo de ^lainique. The pronounced scarp on the northeastern border of the Andes
is seen in the right background.

Fig. 2 — Pushing a heavy dugout against the current in the rapids below Pongo de
Mainique. The Indian boj- and his father in the canoe had been accidentall.v shot.

I'lii. .'! I'roiii i((; t(i Hiif^.ir <';uu', I riihimilni \nllt'V, Jit (*'()l|uiiii. On tlic north-
eaHt<-rn liordi-r nf tlic ('unlillcni Vilcaimmjia looking' ii|)HtrciMii. In tlic cxlroino bnck-
groiimt and thirteen Hixt<'cn(liH of an incli from tlic Inp nf (lie piitnrc is tlic sharp
peak «>f Salcantay. Only the lower einl of the niorr opi n portiDH of the Canyon of
Torontoy is lierc sliown. There iH n field of Kiifjar ciinc in the forr^'rmind and the
valley trail in shown on the r)ppo8ite side of the river.

THE REGIONS OF PERU 3

coastal valleys were small and dry and the men who lived there
were crowded and poor (sic). The plateau was inhabited by In-
dians little better than brutes. Surely I could not think that the
fine forest Indian was lower than the so-called civilized Indian of
the plateau. There was plenty of room in the forest; and there
was wealth if you knew how to get at it. Above all you were far
from the annoying officials of the government, and therefore could
do much as you pleased so long as you paid your duties on rubber
and did not wantonly kill too many Indians.

For all his kindly tolerance of men and conditions he yet found
fault with the government. "They" neglected to build roads, to
encourage colonization, and to lower taxes on the forest products,
which were always won at great risk. Nature had done her part
well — it was only government that hindered. Moreover, the for-
ested region was the land of the future. If Peru was to be a great
nation her people would have to live largely upon the eastern
plains. Though others spoke of "going in" and "coming out" of
the rubber country as one might speak of entering and leaving a
dungeon, he always spoke of it as home. Though he now lived
in the wilderness he hoped to see the day when plantations cov-
ered the plains. A greater Peru and the forest were inseparable
ideas to him.

The Eastern Valley Planter

My second friend lived in one of the beautiful mountain val-
leys of the eastern Andes. We walked through his clean cacao
orchards and cane fields. Like the man in the forest, he believed
in the thorough inefficiency of the government; otherwise why
were there no railways for the cheaper transportation of the val-
ley products, no dams for the generation of power and the storage
of irrigation water, not even roads for mule carts 1 Had the gov-
ernment been stable and efficient there w^ould now be a dense popu-
lation in the eastern valleys. Revolutions were the curse of these
remote sections of the country. The ne'er-do-wells became gen-
erals. The loafer you dismissed today might demand ten thou-
sand dollars tomorrow or threaten to destroy your plantation.

4 THE ANDES OF SOUTHERN PERU

The govermnent troops might come to help you, but they were
always too late.

For this one paid most burdensome taxes. Lima profited
thereby, not the valley planters. The coast people were the
favored of Peru anyhow. They had railroads, good steamer
service, public improvements at government expense, and com-
paratively light taxes. If the government were impartial the
eastern valleys also would have railways and a dense population.
Who could tell? Perhaps the capital city might be here. Cer-
tainly it was better to have Lima here than on the coast where
the Chileans might at any time take it again. The blessings of
the valleys were both rich and manifold. Here was neither a cold
plateau nor the hot plains, but fertile valleys with a vernal climate.

We talked of much else, but our conversation had always the
pioneer flavor. And though an old man he saw always the future
Peru gro\ving wonderfully rich and powerful as men came to rec-
ognize and use the resources of the eastern valleys. This too was
the optimism of the pioneer. Once started on that subject he grew
eloquent. He was provincial but he was also intensely patriotic.
He never missed an opportunity to impress upon his guests that
a great state would arise when people and rulers at last recog-
nized the wealth of eastern Peru.

The Highland Shepherd

The people who live in the lofty highlands and mountains of
Peru have several months of real winter weather despite their
tropical latitude. In the midst of a snowstorm in the Maritime
Cordillera I met a solitary traveler bound for Cotahuasi on the
floor of a deep canyon a day's journey toward the east. It was
noon and wo halted our pack trains in the lee of a huge rock shelter
to escape the bitter wind that blew down from the snow-clad peaks
of Solimana. Men who follow the same trails arc fraternal. In
a moment w(' had food from our saddle-bags spread on the snow
iiiKJcr the coi-iicr of a poncho niid lind exchanged the best in each
other's collection as ii;iliir;illy ;is friends exchange greetings. By
the time I had fold liim wIkiicc and why in response to his inevita-

THE REGIONS OF PERU 6

ble questions we had finished the food and had gathered a heap
of tola bushes for a fire. The arriero (muleteer) brought water
from a spring in the hollow below us. Though the snow thick-
ened, the wind fell. We were comfortable, even at 16,000 feet,
and called the place "The Salamanca Club." Then I questioned
him, and this is what he said:

"I live in the deep valley of Cotahuasi, but my lands lie chiefly
up here on the plateau. My family has held title to this puna ever
since the Wars of Liberation, except for a few years after one of
our early revolutions. I travel about a great deal looking after
my flocks. Only Indians live up here. Away off yonder beyond
that dark gorge is a group of their huts, and on the bright days
of summer you may see their sheep, llamas, and alpacas up here,
for on the floors of the watered valleys that girdle these volcanoes
there are more tender grasses than grow on this despoUado. I
give them corn and barley from my irrigated fields in the valley ;
they give me wool and meat. The alpaca wool is most valuable.
It is hard to get, for the alpaca requires short grasses and plenty
of water, and you see there is only coarse tufted ichu grass about
us, and there are no streams. It is all right for llamas, but alpacas
require better forage.

''No one can imagine the poverty and ignorance of these moun-
tain shepherds. They are filthier than beasts. I have to watch
them constantly or they would sell parts of the flocks, which
do not belong to them, or try to exchange the valuable alpaca wool
for coca leaves in distant towTis. They are frequently drunk."

''But where do they get the drink? " I asked. "And what do
you pay them? "

"Oh, the drink is chiefly imported alcohol, and also chicha made
from corn. They insist on having it, and do better when I bring
them a little now and then. They get much more from the deal-
ers in the towns. As for pay, I do not pay them anything in
money except when they bring meat to the valley. Then I give
them a few reales apiece for the sheep and a little more for the
llamas. The flocks all belong to me really, but of course the poor
Indian must have a little money. Besides, I let him have a part

6 THE ANDES OF SOUTHERN PERU

of the yearly increase. It is not much, but he has always lived
this way and I suppose that he is contented after a fashion."

Then he became eager to tell what wealth the mountains con-
tained in soil and climate if only the right grasses were intro-
duced by the government.

"Here, before us, are vast punas almost without habitations.
If the officials would bring in hardy Siberian grasses these lava-
covered plateaus might be carpeted with pasture. There would be
villages here and there. The native Indians easily stand the alti-
tude. This whole Cordillera might have ten times as many people.
Why does the government bother about concessions in the rubber
forests and roads to the eastern valleys when there are these vast
tracts only requiring new seeds to develop into rich pastures?
The government could thus greatly increase its revenues because
there is a heavy tax on exported wool."

Thus he talked about the bleak Cordillera until we forgot the
pounding of our hearts and our frequent gasps for breath on ac-
count of the altitude. His rosy picture of a well-populated high-
land seemed to bring us do^vn nearer sea level where normal folks
lived. To the Indians the altitude is nothing. It has an effect, but
it is slight; at any rate they manage to reproduce their kind at
elevations that would kill a white mother. If alcohol were abol-
ished and better grasses introduced, these lofty pastures might
indeed support a much larger population. The sheep pastures of
the world are rapidly disappearing before the march of the farmer.
Hero, well above the limit of cultivation, is a permanent range,,
one of the great as well as permanent assets of Peru.

The Coastal Planter

The man from the deep Majcs Valley in the coastal desert rode
out with me through cotton fields as rich and clean as those of a
Texas plantation. He was tall, straight-limbed, and clear-eyed —
one of the energetic younger generation, yet with the blood of a
proud old family. We forded the river and rode on through vine-
yards and fig oreliards loaded with fruit. His manner became
deeply earnest as he pictured the future of Peru, when her people

Fig. 4.

Fig. 5.

Fig. 4 — Large ground moss — so-called i/areta — used for fuel. It occurs in the zone
of Alpine vegetation and is best developed in regions where tlie snowline is highest.
The photograph represents a typical occurrence between Cotahuasi and Salamanca,
elevation 16,000 feet (4,880 m.). The snowline is here at 17,500 feet (.5,333 m.). In
the foreground is the most widely distributed tola bush, also used for fuel.

Fig. 5 — Expedition's camp near Lambrama, 15.500 feet (4,720 m.), after a snow-
storm. The location is midway in the pasture zone.

Fio. G.

5*!^ f

Fici. 7.

Kio. r> — Frri^i't''! ' liili Xiillfv on iln- niitskirls nf Ancmipii. Ilir Idwit hIojx's
of Kl MiNti lire in Hm- Ifit l»ii(kKri»iiii(l. 'I'lic .Wdi ilr Ion JIuchos or l'l;il<;ni of lUmos
licH (»n tlip fnrtlHT >i(ir nf I he vullcy.

Kiu 7 — CroHHiiifi the lii^'lifsl [ihhh (Clni'inilii ) in tlic ('(irdillfin \il<':ii)iiiri|)ii, 14,500
feet (4,420 m.). (Irnziiif^ is licrr carried on up to the snowline.

THE REGIONS OF PERU 7

would take advantage of scientific methods and use labor-saving
machinery. He said that the methods now in use were medieval,
and he pointed to a score of concrete illustrations. Also, here was
water running to waste, yet the desert was on either hand. There
should be dams and canals. Every drop of water was needed.
The population of the valley could be easily doubled.

Capital was lacking but there was also lacking energy among
the people. Slipshod methods brought them a bare living and
they were too easily contented. Their standards of life should be
elevated. Education was still for the few, and it should be uni-
versal. A new spirit of progress was slowly developing — a more
general interest in public affairs, a desire to advance with the
more progressive nations of South America, — and when it had
reached its culmination there would be no happier land than
coastal Peru, already the seat of the densest populations and the
most highly cultivated fields.

These four men have portrayed the four great regions of Peru
— the lowland plains, the'" eastern mountain valleys, the lofty
plateaus, and the valley oases of the coast. This is not all of
Peru. The mountain basins have their own peculiar qualities and
the valley heads of the coastal zone are unlike the lower valleys
and the plateau on either hand. Yet the chief characteristics of
the country are set forth with reasonable fidelity in these indi-
vidual accounts. Moreover the spirit of the Peruvians is better
shown thereby than their material resources. If this is not Peru,
it is what the Peruvians think is Peru, and to a high degree a
man's country is what he thinks it is — at least it is little more to
him.

CHAPTER II
THE RAPIDS AND CANYONS OF THE URUBAMBA

Amoxg the scientifically unexplored regions of Peru there is
no other so alluring to the geographer as the vast forested realm
on the eastern border of the Andes. Thus it happened that within
two weeks of our arrival at Cuzco we followed the northern trail
to the great canyon of the Urubamba (Fig. 8), the gateway to the
eastern valleys and the lowland plains of the Amazon. It is here
that the adventurous river, reenforced by hundreds of mountain-
born tributaries, finally cuts its defiant way through the last of its
great topographic barriers. More than seventy rapids interrupt
its course ; one of them, at the mouth of the Sirialo, is at least a
half-mile in length, and long before one reaches its head he hears
its roaring from beyond the forest-clad mountain spurs.

The great bend of the Urubamba in which the line of rapids
occurs is one of the most curious hydrographic features in Peru.
The river suddenly changes its general northward course and
striking south of west flows nearly fifty miles toward the axis of
the mountains, where, turning almost in a complete circle, it makes
a final assault upon the eastern mountain ranges. Fifty miles
farther on it breaks through the long sharp-crested chain of the
Front Range of the Andes in a splendid gorge more than a half-
mile deep, the famous Pongo de Mainique (Fig. 9).

Our chief object in descending the lino of rapids was to study
the canyon of the Urubamba below Rosalina and to make a topo-
graphic sketcli map of it. Wo also wished to know what secrets
might 1)0 gathered in tliis liilluilo unexplored stretch of country,
what people dwdt along its banks, and if Iho vague tales of de-
serted towns and fugitive tribes had any basis in fact.

We could gather almost no information as to the nature of the
river except from tlie report of Major Korboy, an American, who,
in 1807, descended the last twenty miles of the one hundred we
proposed to navigate, lie i)rc)nounced the journey more hazard-

THE RAPIDS AND CANYONS OF THE URUBAMBA

Pon;fo (le Mainique

ROUGH SKETCH CONTOURMAP

off/if

URUBAMBA VALLEY

BETWEEN ROSALINA

AND PONGO DE MAINIQUE
by

ISAIAH BOWMAN

Aoprox sco/e " f ""-^S

ionlour interval approximately ZOO feet
. rapids

alluvia/ flats, locally called playos
Elevation of Rosalina 2,000 feet

„ // Pongo de Mainique- f.200 feet
„ Passes on frail between Rosalina
and Pongo de Mainique 5000-7.000 ft.

Fig. S — Sketch map showing the route of the Yale- Peruvian Expedition of 1911
clown the Urubamba Valley, together with the area of the main map and the clianges
in the delineation of the bend of the Urubamba resulting from the surveys of the
Expedition. Based on the " Mapa que comprende las ultimas exploraciones y estudios
verificados desde 1900 hasta 190G," 1:1,000,000, Bol. Soc. Geogr. Lima, Vol. 25, No. 3,
1909. For details of the trail from Rosalina to Pongo de Mainique see " Piano de las
Secciones y Afluentes del Rio Urubamba: 1902-1904, scale 1:150,000 by Luis M.
Robledo in Bol. Soc. Geogr. Lima, Vol. 25, No. 4, 1909. Only the lower slopes of
the long mountain spurs can be seen from the river; hence only in a few places could
observations be made on the topography of distant ranges. Paced distances of a half
mile at irregular intervals were used for the estimation of longer distances. Direc-
tions were taken by compass corrected for magnetic deviation as determined on the
seventy-third meridian (See Appendix A). The position of Rosalina on Robledo's
map was taken as a base.

10 THE ANDES OF SOUTHERN PERU

ous than Major Powell's famous descent of the Grand Canyon in
1867 — an obvious exaggeration. He lost his canoe in a treacher-
ous rapid, was deserted by his Indian guides, and only after a
painful march through an all but impassable jungle was he finally
able to escape on an abandoned raft. Less than a dozen have
ventured down since Major Kerbey's day. A Peruvian mining
engineer descended the river a few years ago, and four Italian
traders a year later floated down in rafts and canoes, losing al-
most all of their cargo. For nearly two months they were
marooned upon a sand-bar waiting for the river to subside. At
last they succeeded in reaching Mulanquiato, an Indian settlement
and plantation owned by Pereira, near the entrance to the last
canyon. Their attempted passage of the worst stretch of rapids
resulted in the loss of all their rubber cargo, the work of a year.
Among the half dozen others who have made the journey — Indians
and slave traders from down-river rubber posts — there is no rec-
ord of a single descent without the loss of at least one canoe.

To reach the head of canoe navigation we made a two weeks'
muleback journey north of Cuzco through the steep-walled granite
Canyon of Torontoy, and to the sugar and cacao plantations of the
middle Urubamba, or Santa Ana Valley, where we outfitted. At
Echarati, thirty miles farther on, where the heat becomes more in-
tense and the first patches of real tropical forest begin, we were
obliged to exchange our beasts for ten fresh animals accustomed to
forest work and its privations. Three days later we pitched our
tent f)ii 11)0 river bank at Rosalina, the last outpost of the valley set-
tlem^'iits. As we dropped down the steep mountain slope before
striking the river flood plain, we passed two half-naked Machi-
ganga Indians perched on the limbs of a tree beside the trail, our
first sight of membors of a tribe whose territory we had now en-
tered. Later in the day they crossed the river in a dugout, landed
on the sand-bar above us, and gathered brush for the nightly fire,
around which thoy lie wrapped in a single shirt woven from the
fiber of the wild cotton.

Rosalina is liardly more than a iiani(! on llie map and a camp
site on the river ])ank'. Some distance back from the left bank of

'ji

'"^

«»«

.'"

t«

-1^

•4-1

<*-

',»'

"y.

■= .2-. ti: i:

-' c ^ en

JJEV.

Fig. U.

Imo. 12.

Fio. II— A t<'in|Mir!try i-licllrrliiit (,n :i -iiiHll.:ir iicur (lie j;ic:i) Ixiid of (lie I'm-
bnmhii (Mc- niai), Fif^. H). 'rhc Maclii^'anKu liidiniiH iiw tlicsr < niw slicltcrs duriiif,' the;
I'lHliinK MfHHon, whi'U the river in low.

Kio. 12 — Thirty-foot cjitiof in :i i:i|.i(l uliovr I'onpi dc .M;iiiii(iii(..

THE RAPIDS AND CANYONS OF THE URUBAMBA 11

the river is a sugar plantation, whose owner lives in the cooler
mountains, a day's journey away; on the right bank is a small
clearing planted to sugar cane and yuca, and on the edge of it is
a reed hut sheltering three inhabitants, the total population of
Rosalina. The owner asked our destination, and to our reply that
we should start in a few days for Pongo de Mainique he offered
two serious objections. No one thought of arranging so difficult
a journey in less than a month, for canoe and Indians were diffi-
cult to find, and the river trip was dangerous. Clearly, to start
without the loss of precious time would require unusual exertion.
We immediately despatched an Indian messenger to the owner
of the small hacienda across the river while one of our peons car-
ried a second note to a priest of great influence among the forest
Indians, Padre Mendoza, then at his other home in the distant
mountains.

The answer of Senor Morales was his appearance in person to
offer the hospitality of his home and to assist us in securing canoe
and oarsmen. To our note the Padre, from his hill-top, sent a
polite answer and the offer of his large canoe if we would but
guarantee its return. His temporary illness prevented a visit
to which we had looked forward with great interest.

The morning after our arrival I started out on foot in
company with our arriero in search of the Machigangas, who
fish and hunt along the river bank during the dry season and re-
tire to their hill camps when the heavy rains begin. We soon left
the well-beaten trail and, following a faint woodland path, came
to the river bank about a half day's journey below Rosalina.
There we found a canoe hidden in an overhanging arch of vines,
and crossing the river met an Indian family who gave us further
directions. Their vague signs were but dimly understood and we
soon found ourselves in the midst of a carrizo (reed) swamp
filled with tall bamboo and cane and crossed by a network of inter-
lacing streams. We followed a faint path only to find ourselves
climbing the adjacent mountain slopes away from our destination.
Once again in the swamp we had literally to cut our way through
the thick cane, wade the numberless brooks, and follow wild ani-

12 THE ANDES OF SOUTHERN PERU

mal trails until, late in the day, famished and thirsty, we came
upon a little clearing on a sand-bar, the hut of La Sama, who
knew the Machigangas and their villages.

After our long day's work we had fish and yuca, and water
to which had been added a little raw cane sugar. Late at night
La Sama returned from a trip to the Indian villages down river.
He brought with him a half-dozen Machiganga Indians, boys and
men, and around the camp fire that night gave us a dramatic ac-
count of his fomier trip down river. At one point he leaped to
his feet, and with an imaginary pole shifted the canoe in a swift
rapid, turned it aside from imminent wreck, and shouting at the
top of his voice over the roar of the water finally succeeded in
evading what he had made seem certain death in a whirlpool. We
kept a fire going all night long for we slept upon the ground with-
out a covering, and, strange as it may appear, the cold seemed in-
tense, though the minimum thermometer registered 59° F. The
next morning the whole party of ten sunned themselves for nearly
an hour until the flies and heat once more drove them to shelter.

Returning to camp next day by a different route was an experi-
ence of great interest, because of the light it threw on hidden trails
known only to the Indian and his friends. Slave raiders in former
years devastated the native villages and forced the Indian to con-
ceal his special trails of refuge. At one point we traversed a
cliff seventy-five feet above the river, walking on a narrow ledge
no wider than a man's foot. At another point the dim trail ap-
parently disappeared, but when we had climbed hand over hand
up the face of the cliff, by hanging vines and tree roots, we came
upon it again. Crossing the river in the canoe we had used the
day before, we shortened the return by wading the swift Chi-
rumbia waist-deep, and by crawling along a cliff face for nearly an
eight li of a niilo. At the steepest point the river had so under-
cut the face that there was no trail at all, and we swung fully fif-
teen feet from one lodge to another, on a hanging vine high above
the river.

After two days' delay we left Rosalina late in the afternoon
of August 7. My party included several Machiganga Indians, La

THE RAPIDS AND CANYONS OF THE URUBAMBA 13

Sama, and Dr. W. G. Erving, surgeon of the expedition. Mr. P.
B. Lanius, Moscoso (the arriero), and two peons were to take the
pack train as far as possible toward the rubber station at Pongo
de Mainique where preparations were to be made for our arrival.
At the first rapid we learned the method of our Indian boatmen.
It was to run the heavy boat head on into shallow water at one
side of a rapid and in this way ' ' brake ' ' it down stream. Heavily
loaded with six men, 200 pounds of baggage, a dog, and supplies
of yuca and sugar cane our twenty-five foot dugout canoe was as
rigid as a steamer, and we dropped safely dow^n rapid after rapid
until long after dark, and by the light of a glorious tropical moon
we beached our craft in front of La Sama's hut at the edge ojp
the cane swamp.

Here for five days we endured a most exasperating delay. La
Sama had promised Indian boatmen and now said none had yet
been secured. Each day Indians were about to arrive, but by
nightfall the promise was broken only to be repeated the follow-
ing morning. To save our food supply — we had taken but six
days' provisions — we ate yuca soup and fish and some parched
corn, adding to this only a little from our limited stores. At last
we could wait no longer, even if the map had to be sacrificed to
the work of navigating the canoe. Our determination to leave
stirred La Sama to final action. He secured an assistant named
Wilson and embarked with us, planning to get Indians farther
down river or make the journey himself.

On August 12, at 4.30 P. M., we entered upon the second stage
of the journey. As we shot down the first long rapid and rounded
a wooded bend the view down river opened up and gave us our
first clear notion of the region we had set out to explore. From
mountain summits in the clouds long trailing spurs descend to the
river bank. In general the slopes are smooth-contoured and for-
est-clad from summit to base ; only in a few places do high cliffs
diversify the scenery. The river vista everywhere includes a
rapid and small patches of playa or flood plain on the inside of
the river curves. Although a true canyon hems in the river at
two celebrated passes farther down, the upper part of the river

14. THE ANDES OF SOUTHERN PERU

flows in a somewhat open valley of moderate relief, mth here and
there a sentinel-like peak next the river.

A light shower fell at sunset, a typical late-afternoon down-
pour so characteristic of the tropics. We landed at a small en-
campment of Machigangas, built a fire against the scarred trunk
of a big palm, and made up our beds in the open, covering them
with our rubber ponchos. Our Indian neighbors gave us yuca and
corn, but their neighborliness went no further, for when our boat-
men attempted to sleep under their roofs they drove them out and
fastened as securely as possible the shaky door of their hut.

All our efforts to obtain Indians, both here and elsewhere,
proved fruitless. One excuse after another w^as overcome; they
plainly coveted the trinkets, knives, machetes, muskets, and am-
munition that we offered them; and they appeared to be friendly
enough. Only after repeated assurances of our friendship could
we learn the real reason for their refusal. Some of them were
escaped rubber pickers that had been captured by white raiders
several years before, and for them a return to the rubber country
meant enslavement, heavy floggings, and separation from their
numerous wives. The hardships they had endured, their final
escape, the cruelty of the rubber men, and the difficult passage of
the rapids below were a set of circumstances that nothing in our
list of gifts could overcome. My first request a week before had so
sharpened their memory that one of them related the story of his
wrongs, a recital intensely dramatic to the whole circle of his
listeners, including myself. Though I did not understand the de-
tails of his story, his tones and gesticulations were so effective
that they hold mo as well as his kinsmen of the woods spellbound
for over an hour.

It is appalling to what extent this great region has been de-
^populated by the slave raiders and those arch enemies of the
savage, smallpox and malaria. At liosalina, over sixty Indians
died of malaria in one year; and only twenty years ago seventy of
them, the entire population of the Pongo, were swept away by
smallpox. For a week we passed former camps near small aban-
doned clearings, once the home of little groups of Machigangas.

THE RAPIDS AND CANYONS OF THE URUBAMBA 15

Even the summer shelter huts on the sand-bars, where the Indians
formerly gathered from their hill homes to fish, are now almost
entirely abandoned. Though our men carefully reconnoitered each
one for fear of ambush, the precaution was needless. Below the
Coribeni the Urubamba is a great silent valley. It is fitted by
Nature to support numerous villages, but its vast solitudes are
unbroken except at night, when a few families that live in the hills
slip down to the river to gather yuca and cane.

By noon of the second day's journey we reached the head of
the great rapid at the mouth of the Sirialo. We had already run
the long Coribeni rapid, visited the Indian huts at the junction
of the big Coribeni tributary, exchanged our canoe for a larger
and steadier one, and were now to run one of the ugliest rapids of
the upper river. The rapid is formed by the gravel masses that
the Sirialo brings down from the distant Cordillera Vilcapampa.
They trail along for at least a half-mile, split the river into two
main currents and nearly choke the mouth of the tributary. For
almost a mile above this great barrier the main river is ponded
and almost as quiet as a lake.

We let our craft down this rapid by ropes, and in the last dif-
ficult passage were so roughly handled by our almost unmanagea-
ble canoe as to suffer from several bad accidents. All of the party
were injured in one way or another, while I suffered a fracture
sprain of the left foot that made painful work of the rest of the
river trip.

At two points below Bosalina the Urubamba is shut in by steep
mountain slopes and vertical cliffs. Canoe navigation below the
Sirialo and Coribeni rapids is no more hazardous than on the
rapids of our northern rivers, except at the two "pongos" or nar-
row passages. The first occurs at the sharpest point of the abrupt
curve shown on the map; the second is the celebrated Pongo de
Mainique. In these narrow passages in time of high water there
is no landing for long stretches. The bow paddler stands well
forward and tries for depth and current; the stern paddler keeps
the canoe steady in its course. When paddlers are in agreement
even a heavy canoe can be directed into the most favorable chan-

16 THE AXDES OF SOUTHERN PERU

nels. Our canoemen were always iu disagreement, however, and
as often as not we shot down rapids at a speed of twenty miles an
hour, broadside on, with an occasional bump on projecting rocks
or boulders whose warning ordinary boatmen would not let go
unheeded.

The scenery at the great bend is unusually beautiful. The
tropical forest crowds the river bank, great cliffs rise sheer from
the water's edge, their faces overhung with a trailing drapery of
vines, and in the longer river vistas one may sometimes see the
distant heights of the Cordillera Vilcapampa. We shot the long
succession of rapids in the first canyon without mishap, and at
night pitched our tent on the edge of the river near the mouth of
the Manugali.

From the sharp peak opposite our camp we saw for the first
time the phenomenon of cloud-banners. A light breeze was blow-
ing from the western mountains and its vapor was condensed into
clouds that floated down the Avind and dissolved, while they were
constantly forming afresh at the summit. In the night a thunder-
storm arose and swept with a roar through the vast forest above
us. The solid canopy of the tropical forest fairly resounded with
the impact of the heavy raindrops. The next morning all the
brooks from the farther side of the river were in flood and the
river discolored. When we broke camp the last mist wraiths of
the storm were still trailing through the tree-tops and wrapped
about the peak opposite our camp, only parting now and then to
give us delightful glimpses of a forest-clad summit riding high
above the clouds.

The alternation of deeps and shallows at this point in the river
and the well-devolopod canyon meanders are among the most cele-
brated of their kind in 1lie world. Though shut in by high cliffs
and bordered l)y iiiounlMius llio river exhibits a succession of
curves so regular that one might almost imagine the country a
/ plain from tlie pattern of the meanders. The succession of smooth
curves for a long distance across existing mountains points to a
time when a lowland jilain with moderate slopes drained by
strongly meandering rivers was developed here. Uplift afforded

THE RAPIDS AND CANYONS OF THE URUBAMBA 17

a chance for renewed down-cutting on the part of all the
streams, and the incision of the meanders. The present meanders
are, of course, not the identical ones that were formed on the low-
land plain; they are rather their descendants. Though they still
retain their strongly curved quality, and in places have almost
cut through the narrow spurs between meander loops, they are not
smooth like the meanders of the Mississippi. Here and there are
sharp irregular turns that mar the symmetry of the larger curves.
The alternating bands of hard and soft rock have had a large part
in making the course more irregular. The meanders have re-
sponded to the rock structure. Though regular in their broader
features they are irregular and deformed in detail.

Deeps and shallows are known in every vigorous river, but it is
seldom that they are so prominently developed as in these great
canyons. At one point in the upper canyon the river has been
broadened into a lake two or three times the average width of the
channel and with a scarcely perceptible current ; above and below
the ''laguna," as the boatmen call it, are big rapids with beds so
shallow that rocks project in many places. In the Pongo de
Mainique the river is at one place only fifty feet wide, yet so deep
that there is little current. It is on the banks of the quiet
stretches that the red forest deer grazes under leafy arcades.
Here, too, are the boa-constrictor trails several feet wide and bare
like a roadway. At night the great serpents come trailing down
to the river's edge, where the red deer and the wildcat, or so-
called "tiger," are their easy prey.

It is in such quiet stretches that one also finds the vast colonies
of water skippers. They dance continuously in the sun with an in-
cessant motion from right to left and back again. Occasionally
one dances about in circles, then suddenly darts through the entire
mass, though without striking his equally erratic neighbors. An
up-and-down motion still further complicates the effect. It is posi-
tively bewildering to look intently at the whirling multitude and
try to follow their complicated motions. Every slight breath of
wind brings a shock to the organization of the dance. For though
they dance only in the sun, their favorite places are the sunny

18 THE ANDES OF SOUTHERN PERU

spots in the shade near the bank, as beneath an overhanging tree.
When the wind shakes the foliage the mottled pattern of shade and
sunlight is confused, the dance slows do^vn, and the dancers be-
come bewildered. In a storm they seek shelter in the jungle. The
hot, quiet, sunlit days bring out literally millions of these tiny
creatures.

One of the longest deeps in the whole Urubamba lies just above
the Pongo at Mulanquiato. We drifted down with a gentle cur-
rent just after sunset. Shrill whistles, like those of a steam
launch, sounded from either bank, the strange piercing notes of
the lowland cicada, cicada tibicen. Long decorated canoes, bet-
ter than any we had yet seen, were dra^vn up in the quiet coves.
Soon we came upon the first settlement. The owner, Senor
Pereira, has gathered about him a group of Machigangas, and by
marrying into the tribe has attained a position of great influence
among the Indians. Upon our arrival a gun was fired to announce
to his people that strangers had come, upon which the Machi-
gangas strolled along in twos and threes from their huts, helped
us ashore mth the baggage, and prepared the evening meal. Here
we sat do\\Ti with five Italians, who had ventured into the rubber
fields with golden ideas as to profits. After having lost the larger
part of their merchandise, chiefly cinchona, in the rapids the year
before, they had established themselves here with the idea of pick-
ing rubber. Without capital, they followed the ways of the itiner-
ant rubber picker and had gathered "caucho," the poorer of the
two kinds of rubber. No capital is required; the picker simply
cuts down the likeliest trees, gathers the coagulated sap, and floats
it down-stream to market. After a year of this life they had
g^o^vn restless and were venturing on other schemes for the great
down-river rubber country.

A few weeks later, on returning through the forest, we met
their carriers with a few small bundles, the only part of their
cargo they had saved from tlie river. Without a canoe or the
means to buy one they had built rafts, which were quickly torn to
pieces in the rapids. We, too, should have said "pobres Italianos"
if their venture had not been plainly foolish. The rubber terri-

w c ^ "

•" ^ t.

^ W ;5 r

;; ^ 5^ J-

««

-*-5

-4-J

-^ 1-- o

j; OJ 03

3 .s

- o i-
li C/3 to

Fig. 15.

Via. 10.

j.|(i 15 — Tfip<)f?rii|iliy nnd vcj^ftnl iun from (In- 'I'dcafr ]iiiHH, 7,100 feet ('2,1(!4 rn.),
bftw«M-ii KoHiiliiui 1111(1 I'oiigo (!<■ Miiiiii<iii<'. Sec Fi^'. rt'.ia. TIiIh is in the zone of
fiiaxirnum niitifdll. The (umiilti-nimlMH cIoihIh iirf ty|iifiil i"i<l clinnfjc to nimhiiH in
the enrly nfU-rnoon.

yir,, Ifi — Tin- Kxpcdition'K thirty-foot canoe at. tlic inoiitii of tiic Tinipia below
Pongo fie .Mainifjiie.

THE RAPIDS AND CANYONS OF THE URUBAMBA 19

tory is difficult enough for men with capital; for men with-
out capital it is impossible. Such men either become affiliated
with organized companies or get out of the region when they
can. A few, made desperate by risks and losses, cheat and steal
their way to rubber. Two years before our trip an Italian had
murdered two Frenchmen just below the Pongo and stolen their
rubber cargo, whereupon he was shot by Machigangas under the
leadership of Domingo, the chief who was with us on a journey
from Pongo de Mainique to the mouth of the Timpia. After-
ward they brought his skull to the top of a pass along the forest
trail and set it up on a cliff at the very edge of Machiganga-land
as a warning to others of his kind.

At Mulanquiato we secured five Machigangas and a boy inter-
preter, and on August 17 made the last and most difficult portion
of our journey. We found these Indians much more skilful than
our earlier boatmen. Well-trained, alert, powerful, and with ex-
cellent team-play, they swept the canoe into this or that thread
of the current, and took one after another of the rapids with the
greatest confidence. No sooner had we passed the Sintulini rapids,
fully a mile long, than we reached the mouth of the Pomareni.
This swift tributary comes in almost at right angles to the main
river and gives rise to a confusing mass of standing waves and
conflicting currents rendered still more difficult by the whirlpool
just below the junction. So swift is the circling current of the
maelstrom that the water is hollowed out like a great bowl, a really
formidable point and one of our most dangerous passages ; a little
too far to the right and we should be thrown over against the cliff-
face; a little too far to the left and we should be caught in the
whirlpool. Once in the swift current the canoe became as help-
less as a chip. It was turned this way and that, each turn head-
ing it apparently straight for destruction. But the Indians had
judged their position well, and though we seemed each moment in
a worse predicament, we at last skimmed the edge of the whirl-
pool and brought our canoe to shore just beyond its rim.

A little farther on we came to the narrow gateway of the
Pongo, where the entire volume of the river flows between cliffs

20 THE ANDES OF SOUTHERN PERU

at one point no more than fifty feet apart. Here are concentrated
the worst rapids of the lower Urubamba. For nearly fifteen
miles the river is an unbroken succession of rapids, and once
within its walls the Pongo offers small chance of escape. At some
points we were fortunate enough to secure a foothold along the
edge of the river and to let our canoe down by ropes. At others
we w-ere obliged to take chances with the current, though the great
depth of water in most of the Pongo rapids makes them really less
formidable in some respects than the shallow rapids up stream.
The chief danger here lies in the rotary motion of the water at the
sharpest bends. The effect at some places is extraordinary. A
floating object is carried across stream like a feather and driven
at express-train speed against a solid cliff. In trying to avoid one
of these cross-currents our canoe became turned midstream, we
were thrown this way and that, and at last shot through three
standing waves that half filled the canoe.

Below the worst rapids the Pongo exhibits a swift succession
of natural wonders. Fern-clad cliffs border it, a bush resembling
the juniper reaches its dainty finger-like stems far out over the
river, and the banks are heavily clad with mosses. The great
woods, silent, impenetrable, mantle the high slopes and stretch up
to the limits of vision. Cascades tumble from the cliff summits
or go rippling down the long inclines of the slate beds set almost
on edge. Finally appear the white pinnacles of limestone that hem
in the narrow lower entrance or outlet of the Pongo. Beyond this
passage one suddenly comes out upon the edge of a rolling forest-
clad region, tlie rubber territory, the country of the great woods.
Here the Andean realm ends and Amazonia begins.

J-'roin the summits of the white cliffs 4,000 feet above the river
we were in ;i few days to have one of the most extensive views in
Soutli America. The.broak between the Andean Cordillera and the
liill (lotted plains of the lower Urubamba valley is almost as sharp
as a sliorcliiic. The rolling plains are covered with leagues upon
leagues of dense, shadowy, fever-haunted jungle. The great river
winds through in a Sf-rics of splendid meanders, and with so broad
a channel as to make it visible almost to the horizon. Down river

THE RAPIDS AND CANYONS OF THE URUBAMBA 21

from our lookout one can reach ocean steamers at Iquitos with
less than two weeks of travel. It is three weeks to the Pacific
via Cuzco and more than a month if one takes the route across
the high bleak lava-covered country which we were soon to cross
on our way to the coast at Camana.

CHAPTER in
THE RUBBER FORESTS

The white limestone cliffs at Pongo de Mainique are a bound-
ary between two great geographic provinces (Fig. 17). Down val-
ley are the vast river plains, drained by broad meandering rivers ;

Fio. 17 — Kogional diugrani of the Eastern Andes (here the Cordillera Vilcapampa)
and the adjacent tropical plains. For an explanation of the method of construction
and the HymholiHm of tlie diagram see p. 51.

up valley are the rugged spurs of the eastern Andes and their en-
canyoned streams (Kig. 18). There are outliers of the Andes still
farther toward tlie nortlieast where hangs the inevitable haze of
the tropical horizon, l)ut the country beyond them differs in no
important respect from lliiit immediately below the Pongo.

The foot-path to the summit of llic cliffs is too narrow and

THE RUBBER FORESTS

steep for even the most
agile mules. It is simply
impassable for animals
without hands. In places
the packs are lowered by
ropes over steep ledges
and men must scramble
down from one project-
ing root or swinging vine
to another. In the breath-
less jungle it is a wearing
task to pack in all sup-
plies for the station be-
low the Pongo and to
carry out the season's
rubber. Recently however
the ancient track has been
replaced by a road that
was cut with great la-
bor, and by much blast-
ing, across the mountain
barrier, and at last mule
transport has taken the
place of the Indian.

In the dry season it
is a fair and delightful
country — that on the bor-
der of the mountains. In
the wet season the trav-
eler is either actually ma-
rooned or he must slosh
through rivers of mud
and water that deluge the
trails and break the
hearts of his beasts (Fig.
14). Here and there a

Vilcabam

rAKma

^^^CftfAMP4

qtJet^ira°^DiLLeP^''-~^JpUrubainba

Mt.Salcantay

Fig. 18 — Index map for the nine regional
diagrams in the pages following. A rep-
resents Fig. 17; B, 42; C, 36; D, 32; E, 34;
F, 25; G, 26; and H, 65.

24. THE ANDES OF SOUTHERN PERU

large shallow-rooted tree has come crashing down across the
trail and with its four feet of circumference and ten feet of
plank buttress it is as difficult to move as a house. A new trail
must be cut around it. A little farther on, where the valley-
wall steepens and one may look down a thousand feet of slope
to the bed of a mountain torrent, a patch of trail has become
soaked A\4th water and the mules pick their way, trembling,
across it. Two days from Yavero one of our mules went
over the trail, and though she was finally recovered she died of
her injuries the following night. After a month's work in the
forest a mule must run free for two months to recover. The pack-
ers count on losing one beast out of five for every journey into the
forest. It is not solely a matter of work, though this is terrific;
it is quite largely a matter of forage. In spite of its profusion
of life (Fig. 13) and its really vast wealth of species, the tropical
forest is all but barren of grass. Sugar cane is a fair substitute,
but there are only a few cultivated spots. The more tender leaves
of the trees, the young shoots of cane in the carrizo swamps,
and the grass-like foliage of the low bamboo are the chief substi-
tutes for pasture. But they lead to various disorders, besides re-
quiring considerable labor on the part of the dejected peons who
must gather them after a day's heavy work with the packs.

Overcoming these enormous difficulties is expensive and some
one must pay tlie Ijill. As is usual in a pioneer region, the native
laborer pays a large part of it in unrequited toil ; the rest is paid
by the rubber consumer. For this is one of the cases where a
direct road connects the civilized consumer and the barbarous pro-
ducer. What a story it could tell if a ball of smoke-cured rubber
on a New York dock were endowed with speech — of the wet jungle
path, of enslaved peons, of vile abuses by immoral agents, of all
the toil and sickness that make the tropical lowland a reproach !

In the I'Tiitf'd States the specter of slavery haunted the na-
tional consciciKM' .MliTioHt from the Vx'giuning of national life, and
tlic ghost was laid only at the cost of one of the bloodiest wars in
history. In other countries, as in sugar-producing Brazil, the
freeing of the slaves meant not a war but the verge of financial

Fig. 19.

Fig. 19 — Moss-draped trees in the rain forest near Abra Tocate between Rosalina
and Pongo de Mainique.

Fig. 20 — Yavero, a rubber station on tlie Yavero (Paucartambo) River, a tributary
of the Urubamba. Elevation 1,000 feet (490 m.).

I''i(i. 21 — Clciiriii^' ill (lie lrii|ii(;il fmcHl liclwccii Itosiiliim iiiid I'nliclloii. This
rcjiri'Mt'iitH flic liordcr ri'j;ii»ii when- the forcHt-dwclliii^ Mnclii^aiij^a liidiaim and ilie
nioiinlaiii IndiiiiiM iin'c(. Tlic cIcariiiKH arr <if(n|>ic<l liy Miulii^'aii^'as whose oliicf crops
an* yxwn and corn; in tin- fxlri'mi- upper left hand cunicr arc granny h1o])ch occupied
by f^ncchiia hcrdHincn (unl farnicrH who ^'rnw jKilalocs and furn.

THE RUBBER FORESTS 25

ruin besides a fundamental change in the social order and prob-
lems as complex and wearisome as any that war can bring.
Everjrvvhere abolition was secured at frightful cost.

The spirit that upheld the new founders of the western repub-
lics in driving out slavery was admirable, but as much cannot be
said of their work of reconstruction. We like to pass over those
dark days in our own history. In South America there has lin-
gered from the old slave-holding days down to the present, a labor
system more insidious than slavery, yet no less revolting in its de-
tails, and infinitely more difficult to stamp out. It is called
peonage ; it should be called slavery. In Bolivia, Peru, and Brazil
it flourishes now as it ever did in the fruitful soil of the interior
provinces where law and order are bywords and where the scarcity
of workmen will long impel men to enslave labor when they can-
not employ it. Peonage is slavery, though as in all slave systems
there are many forms under which the system is worked out. We
commonly think that the typical slave is one who is made to work
hard, given but little food, and at the slightest provocation is tied
to a post and brutally whipped. This is indeed the fate of many
slaves or "peons" so-called, in the Amazon forests; but it is no
more the rule than it was in the South before the war, for a peon
is a valuable piece of property and if a slave raider travel five
hundred miles through forest and jungle-swamp to capture an
Indian you may depend upon it that he will not beat him to death
merely for the fun of it.

That unjust and frightfully cruel floggings are inflicted at
times and in some places is of course a result of the lack of official
resti-aint that drunken owners far from the arm of the law some-
times enjoy. When a man obtains a rubber concession from the
government he buys a kingdom. Many of the rubber territories
are so remote from the cities that officials can with great difficulty
be secured to stay at the customs ports. High salaries must be
paid, heavy taxes collected, and grafting of the most flagrant kind
winked at. Often the concessionaire himself is chief magistrate
of his kingdom by law. Under such a system, remote from all
civilizing influences, the rubber producer himself oftentimes a law-

26 THE ANDES OF SOUTHERN PERU

less border character or a downright criminal, no system of gov-
ernment would be adequate, least of all one like peonage that per-
mits or ignores flagrant wrongs because it is so expensive to en-
force justice.

The peonage system continues by reason of that extraordinary
difficulty in the development of the tropical lowland of South
America — the lack of a labor supply. The population of Amazonia
now numbers less than one person to the square mile. The people
are distributed in small groups of a dozen to twenty each in scat-
tered villages along the river banks or in concealed clearings
reached by trails known only to the Indians. Nearly all of them
still live in the same primitive state in which they lived at the
time of the Discovery. In the Urubamba region a single cotton
shirt is worn by the married men and women, while the girls
and boys in many cases go entirely naked except for a loincloth
or a necklace of nuts or monkeys' teeth (Fig. 23). A cane hut
with a thatch to keep out the heavy rains is their shelter and their
food is the yuca, sugar cane, Indian corn, bananas of many kinds,
and fish. A patch of yuca once planted will need but the most
trifling attention for years. The small spider monkey is their
greatest delicacy and to procure it they will often abandon every
other project and return at their o^vn sweet and belated will.

In the midst of this natural life of the forest-dwelling Indian
appears the rubber man, who, to gather rubber, must have rubber
"pickers." If he lives on the edge of the great Andean Cordil-
lera, laborers may be secured from some of the lower valleys, but
they must be paid well for even a temporary stay in the hot and
unhealthful lowlands. Farther out in the great forest country the
plateau Indians will not go and only the scattered tribes remain
from which to recruit laborers. For the nature-life of the Indian
what has the rubber gatherer to offer? Money? The Indian uses
it for ornament only. When T once tried with money to pay an
Indian for a week's services he refused it. In exchange for his
severe labor he wanted nothing more than a fish-hook and a ring,
the two costing not more than a penny apiece! When his love for
ornament has once been gratified the Indian ceases to work. His

-2 ~'

ri a

D 3

-^ .s

S &.

CIS •■«

_ 33

2 0) «
3 iJ

t>.

li]

-tS

-»->

.a
H

Vi3

'cj

43
t3

O c^

r-" P*.T m "— !" ^^

i5 .S rO

~ 1i ^ O o;

• ^

,-*

-i-»

3
m

,_,

'F>

d
OS

•♦1

-S

_oJ

■5'

a
3

-3

<-•

-d

6
ti

aS
>>

a>
>

C
cd

r/5

'■3

'd
-♦J

f/J

(3
OS

■+J

-4-i

-tJ

60 'TIS

•r B

^ OS

d
d

*«

-u

P4 CO

■n

•n

ii
>->

3
-t->

60
60

•f^

5
:3

T3
d

M-(

3
■u

&»

■d

«4i4

♦-<

♦J

-!->
§

-*-*

ol
m

THE RUBBER FORESTS 27

food and shelter and clothing are of the most primitive kind, but
they are the best in the world for him because they are the only
kind he has known. So where money and JSnery fail the lash comes
in. The rubber man says that the Indian is lazy and must be
made to work; that there is a great deal of work to be done and
the Indian is the only laborer who can be found; that if rubber
and chocolate are produced the Indian must be made to produce
them; and that if he will not produce them for pay he must be
enslaved.

It is a law of the rubber country that when an Indian falls into
debt to a white man he must work for the latter until the debt is
discharged. If he runs away before the debt is canceled or if he
refuses to work or does too little work he may be flogged. Under
special conditions such laws are wise. In the hands of the rubber
men they are the basis of slavery. For, once the rubber interests
begin to suffer, the promoters look around for a chance to capture
free Indians. An expedition is fitted out that spends weeks ex-
ploring this river or that in getting on the track of unattached In-
dians. When a settlement is found the men are enslaved and taken
long distances from home finally to reach a rubber property.
There they are given a corner of a hut to sleep in, a few cheap
clothes, a rubber-picking outfit, and a name. In return for these
articles the unwilling Indian is charged any fanciful price that
comes into the mind of his ' ' owner, ' ' and he must thereupon work
at a per diem wage also fixed by the owner. Since his obligations
increase with time, the Indian may die over two thousand dollars
in debt !

Peonage has left frightful scars upon the country. In some
places the Indians are fugitives, cultivating little farms in se-
creted places but visiting them only at night or after carefully re-
connoitering the spot. They change their camps frequently and
make their way from place to place by secret trails, now spending
a night or two under the shelter of a few palm leaves on a sand-
bar, again concealing themselves in almost impenetrable jungle.
If the hunter sometimes discovers a beaten track he follows it only
to find it ending on a cliff face or on the edge of a lagoon where

28 THE ANDES OF SOUTHERN PERU

concealment is perfect. There are tribes that shoot the white man
at sight and regard him as their bitterest enemy. Experience has
led them to believe that only a dead white is a good white, revers-
ing our saying about the North American Indian; and that even
when he comes among them on peaceful errands he is likely to
leave behind him a trail of S5i)hilis and other venereal diseases
scarcely less deadly than his bullets.

However, the peonage system is not hideous everywhere and in
all its aspects. There are white o^vners who realize that in the
long run the friendship of the Indians is an asset far greater than
unwilling service and deadly hatred. Some of them have indeed
intermarried with the Indians and live among them in a state but
little above savagery. In the Mamore country are a few owners
of original princely concessions who have grown enormously
wealthy and yet who continue to live a primitive life among their
scores of illegitimate descendants. The Indians look upon them
as benefactors, as indeed many of them are, defending the Indians
from ill treatment by other whites, giving them clothing and orna-
ments, and exacting from them only a moderate amount of labor.
In some cases indeed the whites have gained more than simple
gratitude for their humane treatment of the Indians, some of
whom serve their masters with real devotion.

When the "rubber barons" wish to discourage investigation
of their system they invite the traveler to leave and he is given
a canoe and oarsmen with which to make liis way out of the dis-
trict. Refusal to accept an offer of canoes and men is a declara-
tion of war. An agent of one of the London companies accepted
such a challenge and was promptly told that he would not leave
the territory alive. The threat would have held true in the case
of a less skilful man. Though Indians slept in the canoes to pre-
vent their seizure, he slipped past the guards in the night, swam
If) tlif opposite shore, and llicro secured a canoe within which ho
made a difficult .ionrney down river to the nearest post wlicro food
and an outfit could be secured.

A, few companies operating on or near the border of the Cordil-
lera have adopted a normal labor system, dependent chiefly upop

THE RUBBER FORESTS 29

people from the plateau and upon the thoroughly willing assist- 1
ance of well-paid forest Indians. The Compaiiia Gomera de
Mainique at Puerto Mainique just below the Pongo is one of these
and its development of the region without violation of native
rights is in the highest degree praiseworthy. In fact the whole
conduct of this company is interesting to a geographer, as it
reflects at every point the physical nature of the country.

The government is eager to secure foreign capital, but in east-
ern Peru can offer practically nothing more than virgin wealth,
that is, land and the natural resources of the land. There are no
roads, virtually no trails, no telegraph lines, and in most cases no
labor. Since the old Spanish grants ran at right angles to the
river so as to give the owners a cross-section of varied resources,
the up-river plantations do not extend do\\Ti into the rubber coun-
try. Hence the more heavily forested lower valleys and plains
are the property of the state. A man can buy a piece of land
down there, but from any tract mthin ordinary means only a
primitive living can be obtained. The pioneers therefore are the
rubber men who produce a precious substance that can stand the
enormous tax on production and transportation. They do not
want the land — only the exclusive right to tap the rubber trees
upon it. Thus there has arisen the concession plan whereby a
large tract is obtained under conditions of money payment or of
improvements that w^ill attract settlers or of a tax on the export.

The "caucho" or poorer rubber of the Urubamba Valley be-
gins at 3,000 feet (915 m.) and the "hevea" or better class is a
lower-valley and plains product. The rubber trees thereabouts
produce 60 grams (2 ozs.) of dry rubber each week for eight
months. After yielding rubber for this length of time a tree is
allowed to rest four or five years. ''Caucho" is produced from
trees that are cut dowTi and ringed with machetes, but it is from
fifty to sixty cents cheaper owing to the impurities that get into
it. The wood, not the nut, of the Palma carmona is used for smok-
ing or "curing" the rubber. The government had long been
urged to build a road into the region in place of the miserable
track — absolutely impassable in the wet season — that heretofore

30 THE ANDES OF SOUTHERN PERU

constituted the sole means of exit. About ten years ago Senor
Kobledo at last built a government trail from Eosalina to Yavero
about 100 miles long. While it is a wretched trail it is better than
the old one, for it is more direct and it is better drained. In the
wet season parts of it are turned into rivers and lakes, but it is
probably the best that could be done with the small grant of twenty
thousand dollars.

With at least an improvement in the trail it became possible
for a rubber company to induce cargadores or packers to trans-
port merchandise and rubber and to have a fair chance of success.
Whereupon a rubber company was organized which obtained a con-
cession of 28,000 hectares (69,188 acres) of land on condition that
the company finish a road one and one-half meters wide to the
Pongo, connecting -with the road which the government had ex-
tended to Yavero. The land given in payment was not continuous
but was selected in lots by the company in such a way as to secure
the best rubber trees over an area several times the size of the
concession. The road was finished by William Tell after four
years ' work at a cost of about seventy-five thousand dollars. The
last part of it was blasted out of slate and limestone and in 1912
the first pack train entered Puerto Mainique.

The first rubber was taken out in November, 1910, and produc-
tive possibilities proved by the collection of 9,000 kilos (19,841
pounds) in eight months.

If a main road were the chief problem of the rubber company
the business would soon be on a paying basis, but for every mile
of road there must be cut several miles of narrow trail (Fig. 14),
as the rubber trees grow scattered about — a clump of a half dozen
here and five hundred feet farther on another clump and only scat-
tered individuals between. Furthermore, about twenty-five years
ago rubber men from llio Ucayali came up hero in Lumches and
canoes jitkI nil down largo nnni])ors of trees within reach of the
water courses and l)y ringing tlie trunks every few feet with
machotoR "blod" tliom rapidly and thus covered a large territory
in a short time, and made huge sums of money when the price of
rubber was high. Only a few of the small trees that were left

THE RUBBER FORESTS 31

are now mature. These, the mature trees that were overlooked,
and the virgin stands farther from the rivers are the present
sources of rubber.

In addition to the trails small cabins must be built to shelter
the hired laborers from the plateau, many of whom bring along
their women folk to cook for them. The combined expense to a
company of these necessary improvements before production can
begin is exceedingly heavy. There is only one alternative for the
prospective exploiter : to become a vagrant rubber gatherer. With
tents, guns, machetes, cloth, baubles for trading, tinned food for
emergencies, and with pockets full of English gold parties have
started out to seek fortunes in the rubber forests. If the friend-
ship of a party of Indians can be secured by adequate gifts large
amounts of rubber can be gathered in a short time, for the Indians
know where the rubber trees grow. On the other hand, many for-
tunes have been lost in the rubber country. Some of the tribes
have been badly treated by other adventurers and attack the new-
comers from ambush or gather rubber for a while only to over-
turn the canoe in a rapid and let the river relieve them of selfish
friends.

The Compania Gomera de Mainique started out by securing the
good-will of the forest Indians, the Machigangas. They come
and go in friendly visits to the port at Yavero. If one of them is
sick he can secure free medicine from the agent. If he wishes
goods on credit he has only to ask for them, for the agent knows
that the Indian's sense of fairness will bring him back to work
for the company. Without previous notice a group of Indians
appears :

"We owe," they announce.

"Good," says the agent, "build me a house."

They select the trees. Before they cut them down they address
them solemnly. The trees must not hold their destruction against
the Indians and they must not try to resist the sharp machetes.
Then the Indians set to work. They fell a tree, bind it mth light
ropes woven from the wild cotton, and haul it to its place. That
is all for the day. They play in the sun, do a little hunting, or

32 THE ANDES OF SOUTHERN PERU

look over the agent's house, touching everything, talking little,
exclaiming much. They dip their wet fingers in the sugar bowl and
taste, turn salt out upon their hands, hold colored solutions from
the medicine chest up to the light, and pull out and push in the
corks of the bottles. At the end of a month or two the house is
done. Then they gather their women and babies together and say :

''Now we go," without asking if the work corresponds with the
cost of the articles they had bought. Their judgment is good how-
ever. Their work is almost always more valuable than the arti-
cles. Then they shake hands all around.

' * We will come again, ' ' they say, and in a moment have disap-
peared in the jungle that overhangs the trail.

With such labor the Compania Gomera de Mainique can do
something, but it is not much. The regular seasonal tasks of road-
building and rubber-picking must be done by imported labor. This
is secured chiefly at Abancay, where live groups of plateau In-
dians that have become accustomed to the warm climate of the
Abancay basin. They are employed for eight or ten months at an
average rate of fifty cents gold per day, and receive in addition
only the simplest articles of food.

At the end of the season the gang leaders are paid a gratifica-
cion, or bonus, the size of which depends upon the amount of rub-
ber collected, and this in turn depends upon the size of the gang
and the degree of willingness to work. In the books of the com-
pany I saw a record of gratificaciones running as high as $600
in uold for a season's work.

Some of the laborers become sick and are cared for by the
agent until they recover or can be sent back to their homes. Most
of them have fever before they return.

Tlie rubber costs the company two soles ($1.00) produced at
^'axcro. 'I'lic two \v<'('ks' Iranspoi-lntioii to Cuzco costs three and
a half soles ($1.75) jxi' twenty-five pounds. The exported rubber,
known 1o <))(• Iradc as Mollendo rubber, in contrast to the finer
"Par.'i" rubber from the lower Amazon, is shipped to TTamburg.
The eost for transportation from port to port is $24.00 per Eng-
lish ton (1,010 kilos). There is a Peruvian tax of 8 per cent of

THE RUBBER FORESTS 33

the net value in Europe, and a territorial tax of two soles ($1.00)
per hundred pounds. All supplies except the few vegetables
grown on the spot cost tremendously. Even dynamite, hoes, cloth-
ing, rice — to mention only a few necessities — must pay the heavy
cost of transportation after imposts, railroad and ocean freight,
storage and agents' percentages are added. The effect of a dis-
turbed market is extreme. When, in 1911, the price of rubber fell
to $1.50 a kilo at Hamburg the company ceased exporting. When it
dropped still lower in 1912 production also stopped, and it is still
doubtful, in view of the growing competition of the East-Indian
plantations with their cheap labor, whether operations will ever be
resumed. Within tliree years no less than a dozen large com-
panies in eastern Peru and Bolivia have ceased operations. In one
concession on the Madre de Dios the withdrawal of the agents and
laborers from the posts turned at last into flight, as the forest
Indians, on learning the company's policy, rapidly ascended the
river in force, committing numerous depredations. The great
war has also added to the difficulties of production.

Facts like these are vital in the consideration of the future of
the Amazon basin and especially its habitability. It was the
dream of Humboldt that great cities should arise in the midst of
the tropical forests of the Amazon and that the whole lowland
plain of that river basin should become the home of happy mil-
lions. Humboldt's vision may have been correct, though a hun-
dred years have brought us but little nearer its realization. Now,
as in the past four centuries, man finds his hands too feeble to con-
trol the great elemental forces which have shaped history. The
most he can hope for in the next hundred years at least is the
ability to dodge Nature a little more successfully, and here and
there by studies in tropical hygiene and medicine, by the substi-
tution of water-power for human energy, to carry a few of the out-
posts and prepare the way for a final assault in the war against
the hard conditions of climate and relief. We hear of the Madeira-
Mamore railroad, 200 miles long, in the heart of a tropical forest
and of the commercial revolution it will bring. Do we realize that
the forest which overhangs the rails is as big as the whole plain

34 THE ANDES OF SOUTHERN PERU

between the Rockies and the Appalachians, and that the proposed
line would extend only as far as from St. Louis to Kansas City,
or from Galveston to New Orleans f

Even if twenty whites were eager to go where now there is but
one reluctant pioneer, we should still have but a halting develop-
ment on account of the scarcity of labor. When, three hundred
years ago, the Isthmus of Panama stood in his way, Gomara
wrote to his king: "There are mountains, but there are also
hands," as if men could be conjured up from the tropical jungle.
From that day to this the scarcity of labor has been the chief dif-
ficulty in the lowland regions of tropical South America. Even
when medicine shall have been advanced to the point where resi-
dence in the tropics can be made safe, the Amazon basin will lack
an adequate supply of workmen. Where Humboldt saw thriving
cities, the population is still less than one to the square mile in
an area as large as fifteen of our Mississippi Valley states. We
hear much about a rich soil and little about intolerable insects;
the climate favors a good growth of vegetation, but a man can
starve in a tropical forest as easily as in a desert; certain tribu-
taries of the Negro are bordered by rich rubber forests, yet not
a single Indian hut may be found along their banks. Will men
of the white race dig up the rank vegetation, sleep in grass ham-
mocks, live in the hot and humid air, or will they stay in the cooler
regions of the north and south? Will they rear children in the
temperate zones, or bury them in the tropics'?

What Gorgas did for Panama was done for intelligent people.
Can it be duplicated in the case of ignorant and stupid laborers?
Shall the white man with wits fight it out mth Nature in a tropical
forest, or fight it out with his equals under better skies?

The tropics must be Avon by strong hands of the lowlier classes
who are ignorant or careless of hygiene, and not by the khaki-clad
robust young men like those who work at Panama. Tropical medi-
cine can do something for these folk, but it cannot do much. And
wo cannot surround every laborer's cottage with expensive
SfTfMis, ()]]('(] difohcK, and well-kept lawns. There is a practical
optimism mthI ;i scnfimoulnl optimism. The one is based on facts;

THE RUBBER FORESTS 36

the other on assumptions. It is pleasant to think that the tropical
forest may be conquered. It is nonsense to say that we are now
conquering it in any comprehensive and permanent way. That
sort of conquest is still a dream, as when Humboldt wrote over a
hundred years ago.

CHAPTER IV
THE FOREST INDIANS

The people of a tropical forest live under conditions not unlike
those of the desert. The Sahara contains 2,000,000 persons within
its borders, a density of one-half to the square mile. This is al-
most precisely the density of population of a tract of equivalent
size in the lowland forests of South America. Like the oases
groups in the desert of aridity are the scattered groups along the
river margins of the forest. The desert trails run from spring to
spring or along a valley floor where there is seepage or an inter-
mittent stream; the rivers are the highways of the forest, the
flowing roads, and away from them one is lost in as true a sense
as one may be lost in the desert.

A man may easily starve in the tropical forest. Before start-
ing on even a short journey of two or three days a forest Indian
stocks his canoe with sugar cane and yuca and a little parched
com. He knows the settlements as well as his desert brother
knows the springs. The Pahute Indian of Utah lives in the irri-
gated valleys and makes annual excursions across the desert to
the distant mountains to gather the seeds of the nut pine. The
Machiganga lives in the hills above the Urubamba and annually
comes down through the forest to the river to fish during the dry
season.

The Machigangas are one of the important tribes of the Ama-
zon basin. Though they are dispersed to some extent upon the
plains their chief groups are scattered through the heads of a
large numbor of valleys near the eastern border of the Andes.
Chief among tlie valleys they occupy are the Pilcopata, Tono,
Pini-pini, Yavero, Yuyato, Shirineiri, Ticumpinea, Timpia, and
Camisea (Fig. 20.'}). In their distribution, in their relations with
each other, in their manner of life, and to some extent in their
personal traits, they display characteristics strikingly like those

THE FOREST INDIANS 37

seen in desert peoples. Though the forest that surrounds them
suggests plenty and the rivers the possibility of free movement
with easy intercourse, the struggle of life, as in the desert, is
against useless things. Travel in the desert is a conflict with heat
and aridity; but travel in the tropic forest is a struggle against
space, heat, and a superabundant and all but useless vegetation.

The Machigangas are one of the subtribes of the Campas In-
dians, one of the most numerous groups in the Amazon Valley. It
is estimated that there are in all about 14,000 to 16,000 of them.
Each subtribe numbers from one to four thousand, and the terri-
tory they occupy extends from the limits of the last plantations —
for example, Rosalina in the Urubamba Valley — downstream be-
yond the edge of the plains. Among them three subtribes are still
hostile to the whites: the Cashibos, the Chonta Campas, and the
Campas Bravos.

In certain cases the Cashibos are said to be anthropophagous,
in the belief that they will assume the strength and intellect of
those they eat. This group is also continuously at war with its
neighbors, goes naked, uses stone hatchets, as in ages past, be-
cause of its isolation and unfriendliness, and defends the entrances
to the tribal huts with dart and traps. The Cashibos are diminish-
ing in numbers and are now scattered through the valley of the
Gran Pajonal, the left bank of the Pachitea, and the Pampa del
Sacramento.^

The friendliest tribes live in the higher valley heads, where
they have constant communication with the whites. The use of the
bow and arrow has not, however, been discontinued among them,
in spite of the wide introduction of the old-fashioned muzzle-load-
ing shotgun, which they prize much more highly than the latest
rifle or breech-loading shotgun because of its simplicity and cheap-

' The Cashibos of the Pachitea are the tribe for whom the Piros besought Herndon
to produce " some great and infectious disease " -which could be carried up the river
and let loose amongst them (Herndon, Exploration of the Valley of the Amazon,
Washington, 1854, Vol. 1, p. 196). This would-be artfulness suggests itself as some-
thing of a match against the cunning of the Cashibos whom rumor reports to imitate
the sounds of the forest animals with such skill as to betray into their hands the
hunters of other tribes (see von Tschudi, Travels in Peru During the Years 1838-1842,
translated from the German by Thomasina Ross, New York, 1849, p. 404).

38 THE ANDES OF SOUTHERN PERU

ness. Accidents are frequent among them owing to the careless
use of fire-arms. On our last day's journey on the Urubamba
above the mouth of the Timpia one of our Indian boys dropped his
canoe pole on the hammer of a loaded shotgun, and not only shot
his own fingers to pieces, but gravely wounded his father (Fig. 2).
In spite of his suffering the old chief directed our work at the
canoe and even was able to tell us the location of the most favora-
ble channel. Though the night that followed was as black as ink,
with even the stars obscured by a rising storm, his directions
never failed. We poled our way up five long rapids without spe-
cial difficulties, now working into the lee of a rock whose location
he knew within a few yards, now paddling furiously across the
channel to catch the upstream current of an eddy.

The principal groups of Machigangas live in the middle Uru-
bamba and its tributaries, the Yavero, Yuyato, Sliirineiri, Ticum-
pinea, Timpia, Pachitea, and others. There is a marked difference
in the use of the land and the mode of life among the different
groups of this subtribe. Those who live in the lower plains and
river ''playas," as the patches of flood plain are called, have a sin-
gle permanent dwelling and alternately fish and hunt. Those that
live on hill farms have temporary reed huts on the nearest sand-
bars and spend the best months of the dry season — April to Oc-
tober — in fishing and drying fish to be carried to their mountain
homes (Fig. 21). Some families even duplicate chacras or farms
at tlie river bank and grow yuca and sugar cane. In latter years
smallpox, malaria, and the rubber hunters have destroyed many
of the river villages and driven the Indians to permanent resi-
dence in the hills or, whoro raids occur, along secret trails to hid-
den camps.

Thoir Rvstom of agriculture is strilciiigly adajited to some im-
jKti-taiit featuiT'S of tropical soil. Tlic tlilii hillside soils of tlie
region are but poorly stocked with linmus, even in their \irgin
condition, {'"alien trees and foliage decay so quickly that the layer
of forest mold is exceedingly thin and the little that is incor-
porated in tlie soil is confined to a shallow surface layer. To meet
those special conditions the Indian makes new clearings by gir-

THE FOREST INDIANS 39

dling and burning the trees. When the soil becomes worn out and
the crops diminish, the old clearing is abandoned and allowed to
revert to natural growth and a new farm is planted to corn and
yucsL. The population is so scattered and thin that the land assign-
ment system current among the plateau Indians is not practised
among the Machigangas. Several families commonly live together
and may be separated from their nearest neighbors by many miles
of forested mountains. The land is free for all, and, though some
heavy labor is necessary to clear it, once a small patch is cleared
it is easy to extend the tract by limited annual cuttings. Local
tracts of naturally unforested land are rarely planted, chiefly be-
cause the absence of shade has allowed the sun to burn out the
limited humus supply and to prevent more from accumulating.
The best soil of the mountain slopes is found where there is the
heaviest growth of timber, the deepest shade, the most humus, and
good natural drainage. It is the same on the playas along the
river ; the recent additions to the flood plain are easy to cultivate,
but they lack humus and a fine matrix which retains moisture
and prevents drought or at least physiologic dryness. Here, too, '
the timbered areas or the cane swamps are always selected for
planting.

The traditions of the Machigangas go back to the time of the
Inca conquest, when the forest Indians, the "Antis," were subju-
gated and compelled to pay tribute.' When the Inca family itself
fled from Cuzco after the Spanish Conquest and sought refuge in
the wilderness it was to the Machiganga country that they came by
way of the Vilcabamba and Pampaconas Valleys. Afterward came
the Spaniards and though they did not exercise governmental au-

^ The early chronicles contain several references to Antisuyu and the Antis.
Garcilaso de la Vega's description of the Inca conquests in Antisuyu are well kno^vn
(Royal Commentaries of the Yncas, Book 4, Chapters 16 and 17, Hakluyt Soc. Pubis.,
Ist Ser., No. 41, 1869 and Book 7, Chapters 13 and 14, No. 45, 1871)." Salcamayhua
who also chronicles these conquests relates a legend concerning the tribute payers
of the eastern valleys. On one occasion, he says, three hundred Antis came laden with
gold from Opatari. Their arrival at Cuzco was coincident with a killing frost that
ruined all the crops of the basin whence tlie three hundred fortunates were ordered
with their gold to the top of the high hill of Paehatucsa (Pachatusun) and there
buried with it (An Account of the Antiquities of Peru, Hakluvt Soc Pubis 1st
Ser., No. 48, 1873).

40 THE ANDES OF SOUTHERN PERU

tliority over the forest Indians they had close relations mth them.
Land grants were made to white pioneers for special services or
through sale and with the land often went the right to exploit the
people on it. Some of the concessions were owned by people w^ho
for generations knew nothing save by hearsay of the Indians who
dwelt in the great forests of the valleys. In later years they have
been exploring their lands and establishing so-called relations
whereby the savage ''buys" a dollar's worth of powder or knives
for whatever number of dollars' worth of rubber the owner may
care to extract from him.

The forest Indian is still master of his lands throughout most
of the Machiganga country. He is cruelly enslaved at the rubber
posts, held by the loose bonds of a desultory trade at others, and
in a few places, as at Pongo de Mainique, gives service for both
love and profit, but in many places it is impossible to establish con-
trol or influence. The lowland Indian never falls into the abject
condition of his Quechua brother on the plateau. He is self-re-
liant, proud, and independent. He neither cringes before a white
nor looks up to him as a superior being. I was greatly impressed
by the bearing of the first of the forest tribes I met in August,
1911, at Santo Anato. I had built a brisk fire and was enjoying
its comfort when La Sama returned with some Indians whom he
had secured to clear his playa. The tallest of the lot, wearing a
colored band of deer skin around his thick hair and a gaudy bunch
of yellow feathers down his back, came up, looked me squarely in
the eye, and asked

*'Tatiry payta?" (What is your name?)

AV'hon I replied he quietly sat down by the fire, helping liimself
to the roasted corn T had prepared in the hot ashes. A few days
hiter wlion we cnmo to the head of a rapid I was busy sketching-in
my topographic Tiiap and did not hoar his twice repeated request
to leave the l)<);it wliilc flic party reconnoiterod ilic r.M])id. AVatch-
ing liis opportunity lie came alongside from the rear — he was
steersman — and, turning just as he was leaving the boat, gave me
a whack in the forehead with his open palm. La Sama saw the
motioTi ;m(l protested. The surly answer was:

THE FOREST INDIANS 41

"I twice asked him to get out and he didn't move. What does
he thinlc we run the canoe to the bank for?"

To him the making of a map was inexplicable ; I was merely a
stupid white person who didn't know enough to get out of a canoe
when told!

The plateau Indian has been kicked about so long that all his
independence has been destroyed. His goods have been stolen, his
services demanded without recompense, in many places he has no
right to land, and his few real rights are abused beyond belief. The
difference between him and the forest Indian is due quite largely
to differences of environment. The plateau Indian is agricultural,
the forest Indian nomadic and in a hunting stage of development ;
the unforested plateau offers no means for concealment of person
or property, the forest offers hidden and difficult paths, easy
means for concealment, for ambush, and for wide dispersal of an
afflicted tribe. The brutal white of the plateau follows altogether
different methods when he finds himself in the Indian country, far
from military assistance, surrounded by fearless savages. He
may cheat but he does not steal, and his brutality is always care-
fully suited to both time and place.

The Machigangas are now confined to the forest, but the limits
of their territory were once farther upstream, where they were in
frequent conflict with the plateau Indians. As late as 1835, ac-
cording to General Miller,^ they occupied the land as far upstream
as the "Encuentro" (junction) of the Urubamba and the Yanatili
(Fig. 53). Miller likewise notes that the Chuntaguirus, "a
superior race of Indians" who lived ''toward the Maranon,"
came up the river "200 leagues" to barter with the people
thereabouts.

"They bring parrots and other birds, monkeys, cotton robes
white and painted, wax balsams, feet of the gran bestia, feather
ornaments for the head, and tiger and other skins, which they ex-
change for hatchets, knives, scissors, needles, buttons, and any
sort of glittering bauble."

= Notice of a Journey to the Northward and also to the Northeastward of Cuzco.
Royal Geog. Sec. Journ., Vol. fi, 1836, pp. 174-186.

42 THE ANDES OF SOUTHERN PERU

On their yearly excursions they traveled in a band numbering
from 200 to 300, since at the mouth of the Paucartambo (Yavero)
they were generally set upon by the Pucapacures. The journey
upstream required three months; with the current they returned
home in fifteen days.

Their place of meeting at the mouth of the Yanatili was a
response to a long strip of grassland that extends down the deep
and dry Urubamba Valley, as shown in Figs. 53-B and 55. The
wet forests, in which the Machigangas live, cover the hills back
of the valley plantations; the belt of dry grassland terminates
far within the general limits of the red man's domain and only
2,000 feet above the sea. It is in this strip of low grassland that
on the one hand the highland and valley dwellers, and on the other
the Indians of the hot forested valleys and the adjacent lowland
found a convenient place for barter. The same physiographic
features are repeated in adjacent valleys of large size that drain
the eastern aspect of the Peruvian Andes, and in each case they
have given rise to the periodic excursions of the trader.

These annual journeys are no longer made. The planters have
crept down valley. The two best playas below Rosalina are now
being cleared. Only a little space remains between the lowest val-
ley plantations and the highest rubber stations. Furthermore, the
Indians have been enslaved by the rubber men from the Ucayali.
'J'he Macliigangas, many of whom are runaway peons, will no
hmgor take cargoes down valley for fear of recapture. They have
the cautious spirit of fugitives except in their remote valleys.
'I'JH'ii' llioy are secure and now and tlicn reassert their old spirit
wlicii ;i lawless trader tries to browbeat them into an unprofitable
trade. Also, they are yielding to the alluring call of the planter.
At Santo Anato they are clearing a playa in exchange for am-
nmnitioii, inaclietes, brandy, and baubles. They no longer make
animal excursions to get these things. They have only to call at
the nearest jdanlafion. Tliei'e is always a wolf before the door of
thr' planter — the laek ol' labor. Yet, as on every frontier, he turns
wolf liimsolf wlieii the lambs come, and without shame takes a
week's work for a penny mirror, or, worse still, supplies them

THE FOREST INDIANS 43

with firewater, for that will surely bring them back to him. Since \
this is expensive they return to their tribal haunts with nothing
except a debauched spirit and an appetite from which they can-
not run away as they did from their task masters in the rubber
forest. Hence the vicious circle : more brandy, more labor ; more
labor, more cleared land; more cleared land, more brandy; more
brandy, less Indian. But by that time the planter has a large
sugar estate. Then he can begin to buy the more expensive
plateau labor, and in turn debauch it.

Nature as well as man works against the scattered tribes of
Machigangas and their forest kinsmen. Their country is exceed-
ingly broken by ramifying mountain spurs and valleys overhung
with cliffs or bordered by bold, wet, fern-clad slopes. It is
useless to try to cut your way by a direct route from one
point to another. The country is mantled with heavy forest.
You must follow the valleys, the ancient trails of the people. The
larger valleys offer smooth sand-bars along the border of which
canoes may be towed upstream, and there are little cultivated
places for camps. But only a few of the tribes live along them,
for they are also more accessible to the rubbermen. The smaller
valleys, difficult of access, are more secure and there the tribal rem-
nants live today. While the broken country thus offers a refuge
to fugitive bands it is the broken country and its forest cover that
combine to break up the population into small groups and keep
them in an isolated and quarrelsome state. Chronic quarreling
is not only the product of mere lack of contact. It is due to many
causes, among which is a union of the habit of migration and
divergent tribal speech. Every tribe has its own peculiar words
in addition to those common to the group of tribes to which it be-
longs. Moreover each group of a tribe has its distinctive words.
I have seen and used carefully prepared vocabularies — no two of
which are alike throughout. They serve for communication with
only a limited number of families*. These peculiarities increase
as experiences vary and new situations call for additions to or
changes in their vocabularies, and when migrating tribes meet
their speech may be so unlike as to make communication difficult.

44 THE ANDES OF SOUTHERN PERU

Thus arise suspicion, misunderstanding, plunder, and chronic war.
Had they been a united people their defense of their rough coun-
try might have been successful. The tribes have been divided and
now and again, to get firearms and ammunition with which to raid
a neighbor, a tribe has joined its fortunes to those of vagrant rub-
ber pickers only to find in time that its women were debased, its
members decimated by strange and deadly diseases, and its old
morality undermined by an insatiable desire for strong drink.*

/The Indian loses whether with the white or against him.

The forest Indian is held by his environment no less strongly
than the plateau Indian. We hear much about the restriction of
the plateau dweller to the cool zone in which the llama may live.

/ As a matter of fact he lives far below the cool zone, where he no
longer depends upon the llama but rather upon the mule for trans-
port. The limits of his range correspond to the limits of the
grasslands in the dry valley pockets already described (p. 42), or
on the drier mountain slopes below the zone of heaviest rainfall
(Fig. 54). It is this distribution that brought him into such in-
timate contact with the forest Indian. The old and dilapidated
coca terraces of the Quechuas above the Yanatili almost overlook
the forest patches where the Machigangas for centuries built their
rude huts. A good deal has been written about the attempts of
the Incas to extend their rule into this forest zone and about the
failure of these attempts on account of the tropical climate. But
tlio forest Indian was held by bonds equally secure. The cold cli-
mate of the plateau repelled him as it does today. His haunts are
tlic liot valleys where he need wear only a wild-cotton shirt or
where he may go naked altogether. That he raided the lands of
the plateau Indimi is certain, but he could never displace him.
Only along Ihc coinnioii borders of their domains, where the
climates of two zones merged iiilo each other, could Ihc forest
hidinii ;m(l the jihitcnu Indian seriously (lis|)utc c'lcli other's

♦ Wnlln fltatoH ( Lc IVroii TCcoiu»niiq)ic, rmiH, 1007, p. 207) tlint the Conibos, a
tritKi nf tlio rcnyali, mnkc nnniia] rjtrrcriaa or iniiln <]iiriii|X (Ik- months of July,
AugUNt, nnd Sc'ptfmlnT, thnt in during the senson of low wattr. Over seven hundred
canoes are said to pnrticipnt«' and the captives secured are sold to rubber exploiters,
wlio, indeed, frequently nid in tlie orfjaniz.if ion of the raids.

THE FOREST INDIANS 45

claims to the land. Here was endless conflict but only feeble
trade and only the most minute exchanges of cultural elements.

Even had they been as brothers they would have had little in-
centive to borrow cultural elements from each other. The forest
dweller requires bow and arrow; the plateau dweller requires a
hoe. There are fish in the warm river shallows of the forested
zone; llamas, vicuna, vizcachas, etc., are a partial source of food
supply on the plateau. Coca and potatoes are the chief products
of the grassy mountain slopes ; yuca, corn, bananas, are the chief
vegetable foods grown on the tiny cultivated patches in the forest.
The plateau dweller builds a thick-walled hut; the valley dweller
a cane shack. So unlike are the two environments that it would
be strange if there had been a mixture of racial types and cul-
tures. The slight exchanges that were made seem little more than
accidental. Even today the Machigangas who live on the highest
slopes own a few pigs obtained from Quechuas, but they never
eat their flesh ; they keep them for pets merely. I saw not a single
woolen article among the Indians along the Urubamba whereas
Quechuas with woolen clothing were going back and forth regu-
larly. Their baubles were of foreign make; likewise their few
hoes, likewise their guns.

They clear the forest about a wild-cotton tree and spin and
weave the cotton fiber into sacks, cords for climbing trees when
they wish to chase a monkey, ropes for hauling their canoes, shirts
for the married men and women, colored head-bands, and fish nets.
The slender strong bamboo is gathered for arrows. The chunta
palm, like bone for hardness, supplies them with bows and ar-
row heads. The brilliant red and yellow feathers of forest birds,
also monkey bones and teeth,- are their natural ornaments. Their
life is absolutely distinct from that of their Quechua neighbors.
Little wonder that for centuries forest and plateau Indians have
been enemies and that their cultures are so distinct, for their
environment everywhere calls for unlike modes of existence and
distinct cultural development.

CHAPTER V

THE COUNTRY OF THE SHEPHERDS

The lofty mountain zones of Peru, the high bordering valleys,
and the belts of rolling plateau between are occupied by tribes of
shepherds. In that cold, inhospitable region at the top of the
country are the highest permanent habitations in the world —
17,100 feet (5,210 m.) — the loftiest pastures, the greatest degree
of adaptation to combined altitude and frost, lit is here only a
step from Greenland to Arcady. Nevertheless it is Greenland that
has the people. Why do they shun Arcady? To the traveler from
the highlands the fertile valleys between 5,000 and 8,000 feet (1,500
to 2,5U0 m.) seem like the abode of friendly spirits to whose charm
the highland dweller must yield. Every pack-train from valley
to highland carries luxury in the form of fruit, coca, cacao, and
sugar. One would think that every importation of valley products
would be followed by a wave of migration from highland to val-
ley. fOn the contrary the highland people have clung to their lofty
pastures for unnumbered centuries. Until the Conquest the last
outposts of the Incas toward the east were the grassy ridges that
terminate a few thousand feet below the timber line.

In this natural grouping of the people where does choice or
blind prejudice or instinct leave offf Where does necessity be-
gin? There are answers to most of these questions to be found
in the broad field of geographic comparison. But before we begin
comparisons we must study the individual facts upon which they
rest. These facts are of almost every conceivable variety. They
range in iiiiport.nicc li-oiii n liumble shepherd's stone corral on a
mountain slope to a thickly settled mountain basin. Their in-
terpretation is to be sought now in the soil of rich playa lands,
now in the fixed climatic zones and rugged relief of dee])ly dis-
sected, lofty highlands in the tropics. Some of the controlling
factors are historical, others economic; still other factors have

•jr.

THE COUNTRY OF THE SHEPHERDS 47

■exerted their influence through obscure psychologic channels al-
most impossible to trace. The why of man's distribution over the
earth is one of the most complicated problems in natural science,
and the solution of it is the chief problem of the modern
geographer.

At first sight the mountain people of the Peruvian Andes seem
to be uniform in character and in mode of life. The traveler's
first impression is that the same stone-walled, straw-thatched type
of hut is to be found everywhere, the same semi-nomadic life, the
same degrees of poverty and filth. Yet after a little study the
diversity of their lives is seen to be, if not a dominating fact, at
least one of surprising importance. Side by side with this di-
versity there runs a corresponding diversity of relations to their
physical environment. Nowhere else on the earth are greater phys-
ical contrasts compressed within such small spaces. If, there-
fore, we accept the fundamental theory of geography that there is
a general, necessary, varied, and complex relation between man
and the earth, that theory ought here to find a really vast num-
ber^ of illustrations. A glance at the accompanying figures dis-
closes the wide range of relief in the Peruvian Andes. The cor-
responding range in climate and in life therefore furnishes an am-
ple field for the application of the laws of human distribution.

In analyzing the facts of distribution we shall do well to begin
with the causes and effects of migration. Primitive man is in no
small degree a wanderer. His small resources often require him
to explore large tracts. As population increases the food quest
becomes more intense, and thus there come about repeated emigra-
tions which increase the food supply, extend its variety, and draw
the pioneers at last into contact with neighboring groups. The
farther back we go in the history of the race the clearer it becomes
that migrations lie at the root of much of human development.
The raid for plunder, women, food, beasts, is a persistent feature
of the life of those primitive men who live on the border of un-
like regions.

The shepherd of the highland and the forest hunter of the
plains perforce range over vast tracts, and each brings back to the

48 THE ANDES OF SOUTHERN PERU

home group news that confirms the tribal choice of habitation or
sets it in motion toward a more desirable place. Superstitions
may lead to flight akin to migration. Epidemics may be inter-
preted as the work of a malignant spirit from which men must flee.
War may drive a defeated group into the fastnesses of a moun-
tain forest where pursuit by stream or trail weakens the pursuer
and confines his action, thereby limiting his power. Floods may
come and destroy the cultivated spots. Want or mere desire in a
hundred forms may lead to movement.

Even among forest tribes long stationary the facile canoe and
the light household necessities may easily enable trivial causes to
develop the spirit of restlessness. Pressure of population is a
powerful but not a general cause of movement. It may affect the
settled groups of the desert oases, or the dense population of fer-
tile plains that is rooted in the soil. On the other hand mere
whims may start a nomadic group toward a new goal. Often the
goal is elusive and the tribe turns back to the old haunts or per-
ishes in the shock of unexpected conflict.

In the case of both primitive societies and those of a higher
order the causes and the results of migration are often contra-
dictory. These will depend on the state of civilization and the ex-
tremes of circumstance. (When the desert blooms the farmer of
the Piura Valley in northwestern Peru turns shepherd and drives
his flocks of sheep and goats out into the short-lived pastures
of the great pampa on the west. In dry years he sends them
eastward into the mountains. "^ The forest Indian of the lower Uru-
bamba is a fisherman while the river is low and lives in a reed hut
beside his cultivated patch of cano and yncn. When the floods
come he is driven to the higher ground in the hills where he has
another cultivated patch of land and a rude shelter. To be sure,
these are aeasoiial Tnii::rarK)ns, yet through ilicm \ho country be-
comes betlci- kiiowTi 1() cacli new generation of men. And each
general ion supplies its pioneers, who drift into the remoter places
where poj)ulation is scarce or altogether wanting.

Dry years and extremely dry years may have o])p()sitc effects.
When moderate dryness prevails the results may be endurable.

THE COUNTRY OF THE SHEPHERDS 49

The oases become crowded with men and beasts just when they
can ill afford to support them. The alfalfa meadows become over-
stocked, and cattle become lean and almost worthless. But there
is at least bare subsistence. By contrast, if extreme and pro-
longed drought prevails, some of the people are driven forth to
more favored spots. At Vallenar in central Chile some of the
workmen in extreme years go up to the nitrate pampa; in wet
years they return. When the agents of the nitrate companies hear
of hard times in a desert valley they oifer employment to the
stricken people. It not infrequently happens that when there are
droughts in desert Chile there are abundant rains in Argentina
on the other side of the Cordillera. There has therefore been for
many generations an irregular and slight, though definite, shift-
ing of population from one side of the mountains to the other as
periods of drought and periods of rain alternated in the two
regions. Some think there is satisfactory evidence to prove that
a number of the great Mongolian emigrations took place in wet
years when pasture was abundant and when the pastoral nomad
found it easy to travel. On the other hand it has been urged that
the cause of many emigrations was prolonged periods of drought
when the choice lay between starvation and flight. It is evident
from the foregoing that both views may be correct in spite of the
fact that identical effects are attributed to opposite causes.

It is still an open question w^hether security or insecurity is
more favorable for the broad distribution of the Peruvian Indians
of the mountain zone which forms the subject of this chapter. Cer-
tainly both tend to make the remoter places better known. Tradi-
tion has it that, in the days of intertribal conflict before the Con-
quest, fugitives fled into the high mountain pastures and lived in
hidden places and in caves. Life was insecure and relief was
sought in flight. On the other hand peace has brought security
to life. The trails are now safe. A shepherd may drive his flock
anywhere. He no longer has any one to fear in his search for new
pastures. It would perhaps be safe to conclude that there is
equally broad distribution of men in the mountain pastures in time
of peace and in time of war. There is, however, a difference in

THE ANDES OF SOUTHERN PERU

I'KJ. 2ij — Uff^ional diagram for tlio Maritiinc Cordillora to hIiow the pliysical
rclationH in tlu* distrift wliorc tlic liighcst liahitatiniis in the world are located. For
location, m-e Fig. 20. It Hliould be romcmhcrcd tliat tiio orientation of these diagrama
IB generalized. By reference to Fig. 20 it will he seen that soine ])()r(iiiiiH of the
crest of the Maritime Cordillera run east and west and others iinrlli and south. The
Bame i« true of the Cordillera Vileapampa, Fig. .'{(».

tlic kind of distribution, in time of peace the individual is safe
anywhere; in time of unrest lie is safe only when isolated and vir-
tually concealed. By contrast, the p^roup living near the trails is

THE COUNTRY OF THE SHEPHERDS 51

scattered by plundering bands and war parties. The remote and
isolated group may successfully oppose the smaller band and the
individuals that might reach the remoter regions. The fugitive
group would have nothing to fear from large bands, for the
limited food supply would inevitably cause these to disintegrate
upon leaving the main routes of travel. Probably the fullest ex-
ploration of the mountain pastures has resulted from the alterna-
tion of peace and war. The opposite conditions which these estab-
lish foster both kinds of distribution ; hence both the remote group
life encouraged by war and the individual's lack of restraint in

jVofe on regional diagrams. — For the sake of clearness I have classified the accom-
panying facts of human distribution in the country of the shepherds and represented
them graphically in "regional" diagrams, Figs. 17, 25, 26, 32, 34, 36, 42, 65. These
diagrams are constructed on the principle of dominant control. Each brings out the
factors of greatest importance in the distribution of the people in a given region.
Furthermore, the facts are compressed within the limits of a small rectangle. This com-
pression, though great, respects all essential relations. For example, every location on
these diagrams has a concrete illustration but the accidental relations of the field have
been omitted; the essential relations are preserved. Each diagram is, therefore, a
kind of generalized type map. It bears somewhat the same relation to the facts of
human geography that a block diagram does to physiography. The darkest shading
represents steep snow-covered country; the next lower grade represents rough but
snow-free country; the lightest shading represents moderate relief; unshaded parts
represent plain or plateau. Small circles represent forest or woodland; small open-
spaced dots, grassland. Fine alluvium is represented by small closely spaced dots;
coarse alluvium by large closely spaced dots.

To take an illustration. In Figure 32 we have the Apurimac region near Pasaje
(see location map. Fig. 20). At the lower edge of the rectangle is a snow-capped
outlier of the Cordillera Vilcapampa. The belt of rugged country represents the
lofty, steep, exposed, and largely inaccessible ridges at the mid-elevations of the
mountains below the glaciated slopes at the heads of tributary valleys. The villages
in the belt of pasture might well be Incahuasi and Corralpata. The floors of the
large canyons on either hand are bordered by extensive alluvial fans. The river
courses are sketched in a diagrammatic way only, but a map would not be diflferent
in its general disposition. Each location is justified by a real place with the same
essential features and relations. In making the change there has been no alteration
of the general relation of the alluvial lands to each other or to the highland. By
suppressing unnecessary details there is produced a diagram whose essentials have
simple and clear relations. When such a regional diagram is amplified by
photographs of real conditions it becomes a sort of generalized picture of a
large group of geographic facts. One could very well extend the method to the
whole of South America. It would be a real service to geography to draw up a set
of, say, twelve to fifteen regional diagrams, still further generalized, for the whole
of the continent. As a broad classification they would serve both the specialist and
the general student. As the basis for a regional map of South America they would
be invaluable if worked out in sufficient detail and constructed on the indispensable
basis of field studies.

52 . THE ANDES OF SOUTHERN PERU

time of peace are probably in large part responsible for the pres-
ent widespread occupation of the Peruvian mountains.

The loftiest habitation in the world (Fig. 24) is in Peru. Be-
tween Antabamba and Cotahuasi occur the highest passes in the
Maritime Cordillera. We crossed at 17,400 feet (5,300 m.), and
three hundred feet lower is the last outpost of the Indian shep-
herds. The snowline, very steeply canted away from the sun, is
between 17,200 and 17,600 feet (5,240 to 5,360 m.). At frequent
intervals during the three months of winter, snowfalls during the
night and terrific hailstorms in the late afternoon drive both shep-
herds and flocks to the shelter of leeward slopes or steep canyon
walls. At our six camps, between 16,000 and 17,200 feet (4,876
and 5,240 m.), in September, 1911, the minimum temperature
ranged from 4° to 20° F. The thatched stone hut that we passed
at 17,100 feet and that enjoys the distinction of being the highest
in the world was in other respects the same as the thousands of
others in the same region. It sheltered a family of five. As we
passed, three rosy-cheeked children almost as fat as the sheep
about them were sitting on the ground in a corner of the corral
playing with balls of wool. Hundreds of alpacas and sheep
grazed on the hill slopes and valley floor, and their tracks showed
plainly that they were frequently driven up to the snoAvline in
those valleys where a trickle of water supported a band of pasture.
Less than a hundred feet below them were other huts and flocks.

Here we have the limits of altitude and the limits of resources.
The intervalley spaces do not support grass. Some of them are
quite bare, others are covered with mosses. It is too high for even
the tola bush — that pioneer of Alpine vegetation in the Andes.
Tlic illstance' to Cotahuasi is 75 miles (120 km.), to Aii(;ib;niil)a
r)() iniloa (80 km.). Tlionco wool must bo Khipixnl l)y pack-train
1() tlic r.'iilrond in I lie one case 250 miles (400 km.) lo .\r('(|iiii);i. in
tlic otlier case 200 miles (.'520 km.) to Cuzco. l^^vcii the potatoes
and l)Mrley, wliicli must ))o imported, come from valleys several
days' journey ;i\v;iy. Tiie question naturally arises why these peo-
ple live on the rim of the woi-Jd. Did they seek out these neglected

• DisinnccB nre not taken from thp map but from the trnil.

THE COUNTRY OF THE SHEPHERDS 53

pastures, or were they driven to them? Do they live here by
choice or of necessity? The answer to these questions introduces
two other geographic factors of prime importance, the one phys-
ical, the other economic. ^
\ The main tracts of lofty pasture above Antabamba cover moun-
tain slopes and valley floor alike, but the moist valley floors supply
the best grazing. Moreover, the main valleys have been inten-
sively glaciated. Hence, though their sides are steep walls, their
floors are broad and flat. Marshy tracts, periodically flooded, are
scattered throughout, and here and there are overdeepened por-
tions where lakes have gathered. There is a thick carpet of grass,
also numerous huts and corrals, and many flocks. At the upi^er
edge of the main zone of pasture the grasses become thin and w^ith
increasing altitude give out altogether except along the mplst val-
ley floors or on shoulders where there is seepage.

If the streams head in dry mountain slopes without snow^ the
grassy bands of the valley floor terminate at moderate elevations.
If the streams have their sources in snowfields or glaciers there is
a more uniform run-off, and a ribbon of pasture may extend to the
snowline. To the latter class belong the pastures that support
these remote people.

In the case of the Maritime Andes the great elevation of the
snowline is also a factor. If, in Figure 25, we think of the snow-
line as at the upper levfel of the main zone of pasture then we
should have the conditions shown in Figure 36, where the limit of
general, not local, occupation is the snowline, as in the Cordillera
Vilcapampa and between Chuquibambilla and Antabamba.

A third factor is the character of the soil. Large amounts of
volcanic ash and lapilli were thrown out in the late stages of vol-
canic eruption in which the present cones of the Maritime Andes
were formed. The coarse texture of these deposits allows the
ready escape of rainwater. The combination of extreme aridity
and great elevation results in a double restraint upon vegetation.
Outside of the moist valley floors, with their film of ground
moraine on whose surface plants find a more congenial soil, there
is an extremely small amount of pasture. | Here are the natural

54 THE ANDES OF SOUTHERN PERU

grazing grounds of the tleet vicuna. Tliey occur in hundreds, and
so remote and little disturbed are they that near the main pass
one may count them by the score. As we rode by, many of them
only stared at us without taking the trouble to get beyond rifle
shot. It is not difficult to believe that the Indians easily shoot
great numbers in remote valleys that have not been hunted for
years.

1 The extreme conditions of life existing on these lofty plateaus
are well sho^\Ti by the readiness with which even the hardy shep-
herds avail themselves of shelter. Wherever deep valleys bring a
milder climate within reach of the pastures the latter are unpopu-
lated for miles on either side. The sixty-mile stretch between
Chuquibamba and Salamanca is without even a single hut, though
there are pastures superior to the ones occupied by those loftiest
huts of all. Likewise there are no permanent homes between Sala-
manca and Cotahuasi, though the shepherds migrate across the
belt in the milder season of rain. Eastward and northward to-
ward the crest of the Maritime Cordillera there are no huts
within a day's journey of the Cotahuasi canyon. Then there is a
group of a dozen just under the crest of the secondary range that
parallels the main chain of volcanoes. Thence northward there
are a number of scattered huts between 15,500 and 16,500 feet
(4,700 and 5,000 m.), until we reach the highest habitations of all
at 17,100 feet (5,210 m.).

The unpopulated belts of lava plateau bordering the entrenched
valleys arc, liowever, as distinctly "sustenance" spaces, to use
Penck's term, as the irrigated and fertile alluvial fans in the bot-
tom of the valley. This is well shown when the rains come and
flocks of llamas and sheep are driven forth from the valleys to the^
best pastures, li is equally well shown by the distribution'^of the
shepherds' homes. Those are not down on llic wjinii (•.•luyoii lloor,
separated by a li.ill" d.iy's journey from the grazing. They are in
tlic intrenched liihntary valleys of Figure 20 or just within the
rim <.f tlie canyon. It is not shelter from the cold but^ from the
wind tliat chiefly determines their location. They are also kept
near the rim of the canyon })y the pressure of th(^ farming popu-

THE COUNTRY OF THE SHEPHERDS

lation from below. Every hundred feet of descent from the arid
plateau (Fig. 29) increases the water supply. Springs increase
in number and size; likewise belts of seepage make their appear-
ance. The gradients in many places diminish, and flattish spurs
and shoulders interrupt the generally steep descents of the canyon

Fig. 26 — Regional diagram to show the physical relations in the lava plateau of
the Maritime Cordillera west of the continental divide. For location, see Fig. 20.
Trails lead up the intrenched tributaries. If the irrigated bench (lower right corner)
is large, a town will be located on it. Shepherds' huts are scattered about the edge
of the girdle of spurs. There is also a string of huts in the deep sheltered head of
each tributaiy. See also Fig. 29 for conditions on the valley or canyon floor.

w^all. Every change of this sort has a real value to the farmer and
means an enhanced price beyond the ability of the poor shepherd
to pay. If you ask a wealthy hacendado on the valley floor (Fig.
29), who it is that live in the huts above him, he will invariably say
"los Indios," w^ith a shrug meant to convey the idea of poverty
and worthlessness. Sometimes it is "los Indios pobres," or
merely "los pobres." Thus there is a vertical stratification of

56 THE ANDES OF SOUTHERN PERU

society corresponding to the superimposed strata of climate and
land.

At Salamanca (Fig. 62) I saw this admirably displayed under
circumstances of unusual interest. The floor and slopes of the
valley are more completely terraced than in any other valley I
know of. In the photograph, Fig. 30, which shows at least 2,500
feet of descent near the town, one cannot find a single patch of sur-
face that is not under cultivation. The valley is simply filled mth
people to the limit of its capacity. Practically all are Indians, but
with many grades of wealth and importance. When we rode out
of the valley before daybreak, one September morning in 1911,
there was a dead calm, and each step upward carried us into a
colder stratum of air. At sunrise we had reached a point about
2,000 feet above the town, or 14,500 feet (4,420 m.) above sea level.
We stood on the frost line. On the opposite wall of the valley the
line was as clearly marked out as if it had been an irrigating canal.
The light was so fully reflected from the millions of frost crystals
above it that both the mountainside and the valley slopes were
sparkling like a ruffled lake at sunrise. Below the frost line the
slopes were dark or covered with yellow barley and wheat stubble
or green alfalfa.

/ It happened that the frost line was near the line of division
'between corn and potato cultivation and also near the line separat-
ing the steep rough upper lands from the cultivable lower lands.
Not a habitation was in sight above us, except a few scattered
miserable huts near broken terraces, gullied by wet-weather
streams and grown up to weeds and brush. Below us were well-
fiiltivatf'd fields, and the stock was kept in bounds by stone fences
and corrals; above, the half-wild burros and mules roamed about
everywhere, and only the sheep and llamas were in rude enclo-
sures. Tims ill ;i li;iir hour we passed llic rroiillci' Ix'lwccii tlie
agrieulf iiral fnlk Ix'low llic frost line ;ni(l flif sli('))lii'i-(l folk ,'il)ove
it.

In ;i few spots the line followed an irregular course, as where
flatter lands were developed at unusual elevations or where air
drainage altered the normal temperature. And at one place the

Fio. 27.

Fig. 28.

Fig. 27 — Terraced valley slopes at Hiiaynacotas, Cotahnasi Valley, Peru. Eleva-
tion 11,500 feet (3,500 m.).

Fig. 28 — The highly cultivated and thoroughly terraced floor of the Ollantaytambo
Valley at Ollantaytambo. This is a tributary of the Urubamba; elevation, 11,000 feet.

.•.;.'V,.

; :^^

FlO. 29 — C'otuliua.si on the lloor of tlic ('(itnliiiiisi ciiiiyoii. 'Ihc cvcii skyline of the
buckgruund in on u ratlicr <'vcii-toj)|)C(l lavii pliit<'iiu. 'I lie tciijicc nii the lift of the
town in formed on linicMtone, wliich is ovcrhiin hy lava Howh. A lliick (l(|)i)>it of ter-
raced (iliuviiirn inny be wren on the valh-y lloor, and it is on one of the lower terraces
that the eity of ( otahuasi stands, 'ihe hif,'her t<rraec'H are in many eascK too dry for
cultivation. The canyon is nearly 7,<><t() feet {'2,,]:W m.) deeji and has been cut tlir<nit,'h
one hundred principal lava Hows.

THE COUNTRY OF THE SHEPHERDS 57

frost actually stood on the young corn, which led us to speculate
on the possibility of securing from Salamanca a variety of maize
that is more nearly resistant to light frosts than any now grown
in the United States. In the endless and largely unconscious ex-
perimentation of these folk perched on the valley walls a result
may have been achieved ahead of that yet reached by our pro-
fessional experimenters. Certain it is that nowhere else in the
world has the potato been grown under such severe climatic con-
ditions as in its native land of Peru and Bolivia. The hardiest
varieties lack many qualities that we prize. They are small and
bitter. But at least they will grow where all except very few
cultivated plants fail, and they are edible. Could they not be im-
ported into Canada to push still farther northward the limits of
cultivation? Potatoes are now grown at Forts Good Hope and
McPherson in the lower Mackenzie basin. Would not the hardiest
Peruvian varieties grow at least as far north as the continental
timber line? I believe they could be grown still farther north.
They will endure repeated frosts. They need scarcely any cultiva-
tion. Prepared in the Peruvian manner, as chuno, they could be
kept all winter. Being light, the meal derived from them could
be easily packed by hunters and prospectors. An Indian will carry
in a pouch enough to last him a week. Why not use it north of
the continental limit of other cultivated plants since it is the
pioneer above the frost line on the Peruvian mountains ?

The relation between farmer and shepherd or herdsman grows
more complex where deeper valleys interrupt the highlands and
mountains. The accompanying sketch, Fig. 32, represents typical
relations, though based chiefly on the Apurimac canyon and its
surroundings near Pasaje. First there is the snow-clad region at
the top of the country. Below it are grassy slopes, the homes of
mountain shepherds, or rugged mountain country unsuited for
grazing. Still lower there is woodland, in patches chiefly, but with
a few large continuous tracts. The shady sides of the ravines and
the mountains have the most moisture, hence bear the densest
growths. Finally, the high country terminates in a second belt
of pasture below the woodland.

58 THE ANDES OF SOUTHERN PERU

"Whenever streams descend from the snow or woodland coun-
try there is water for the stock above and for irrigation on the
alhivial fan below. But the spur ends dropping off abruptly sev-

Fio. .'52 — Regional diagram representing tlio die]) panyoncd country west of the
KiiHt/'rn (fjrdillcra in tlie region of tlie Apiiriinac. For pliotograph sec Fig. 94. For
furtlirr di-'cription Her uoU' on ngioiial diaf^ninis. j). 51. Nunibers 1, 2, and 3 corre-
spond in |iiiHition to tlie hiiiiic niiiidxTs in l''ig. .'?■'<.

oral thousand feet have a limited area and no running streams,
and tlie ground water is liuudreds of feet down. There is grass
for stock, but there is no water. In some places the stock is driven

-u

■tJ

•n

—

•^

-4-i

H i^

• ^

•<r^

_cS

CC X! £)

2 ^

^ o

;:;;;

-:;

;-<

'tb

'■"'

-fj

"c-

"H-

M-l

■73

-1^

fiH

THE COUNTRY OF THE SHEPHERDS

back and forth every few days. In a few places water is brought
to the stock by canal from the woodland streams above, as at
Corralpata.^ In the same way a canal brings water to Pasaje
hacienda from a woodland strip many miles to the west. The
little canal in the figure is almost a toy construction a few inches

VALLEY ZONE

MOUNTAIN ZONE

Fig. 33 — Valley climates of the canyoned region shown in Fig. 32.

wide and deep and conveying only a trickle of water. Yet on it
depends the settlement at the spur end, and if it were cut the peo-
ple would have to repair it immediately or establish new homes.
The canal and the pasture are possible because the slopes are
moderate. They were formed in an earlier cycle of erosion when
the land was lower. They are hung midway between the rough
mountain slopes above and the steep canyon walls below (Fig. 32).
Their smooth descents and gentle profiles are in very pleasing
contrast to the rugged scenery about them. The trails follow them
easily. Where the slopes are flattest, farmers have settled and
produce good crops of corn, vegetables, and barley. Some farm-
ers have even developed three- and four-story farms. On an al-
luvial fan in the main valley they raise sugar cane and tropical
and subtropical fruits ; on the flat upper slopes they produce corn ;
in the moister soil near the edge of the woodland are fields of
mountain potatoes; and the upper pastures maintain flocks of

' Compare with Rainiondi's description of Quiches on the left bank of the Marafion
at an elevation of 9,885 feet (3,013 m.) : "the few small springs scarcely suffice for
the little patches of alfalfa and other sowings have to depend on the precarious
rains. . . . Every drop of water is carefully guarded and from each spring a series
•of well-like basins descending in staircase fashion make the most of the scant supply."
(El Departamento de Ancachs, Lima, 1873.)

60 THE ANDES OF SOUTHERN PERU

I sheep. In one district this change takes place in a distance that
may be covered in five hours. Generally it is at least a full and
hard day's journey from one end of the series to the other.

Wherever these features are closely associated they tend to be
controlled by the planter in some deep valley thereabouts. Where
they are widely scattered the people are independent, small
groups living in places nearly inaccessible. Legally they are all
under the control of the owners of princely tracts that take in the
whole country, but the remote groups are left almost wholly to
themselves. In most cases they are supposed to sell their few
commercial products to the hacendado who nominally owns their
land, but the administration of this arrangement is left largely to
chance. The shepherds and small farmers near the plantation are
more dependent upon the planter for supplies, and also their
wants are more varied and numerous. Hence they pay for their
better location in free labor and in produce sold at a discount.

So deep are some of the main canyons, like the Apurimac and
the Cotahuasi, that their floors are arid or semi-arid. The fortunes
of Pasaje are tied to a narrow canal from the moist woodland and
a tiny brook from a hollow in the valley wall. Where the water
has thus been brought down to the arable soil of the fans there are
rich plantations and farms. Elsewhere, however, the floor is quite
dry and uncultivated. In small spots here and there is a little
seepage, or a few springs, or a mere thread of water that will not
support a plantation, wherefore there have come into existence
the valley herdsmen and shepherds. Their intimate knowledge of
the moist places is their capital, quite as much as are the cattle and
shoop they own. In a sense their lands are iho neglected crumbs
from tho rich man's table. So we find the shepherd from the hills
invading the valleys just as the valley farmer lias invaded lli"
country of tiu' slieydicrd.

The basin typo of 1o|)ography calls into ex-istence a scl of rela-
tions quite distinct from either of those we have just desci-ibed.
V Figure .'U represeutH the main facts. Tlie rieli and eomparatively
flat floor of the basin supports most of th<' pcoph'. The alluvial
fans tributary thereto are comi)osed of fine material on theii- outer

THE COUNTRY OF THE SHEPHERDS

Fig. 34 — Regional diagram to show the typical physical conditions and relations
in an intermont basin in the Peruvian Andes. The Ciizco basin (see Fig. 37) is an
actual illustration; it should, however, be emphasized that the diagram is not a
" map " of that basin, for whilst conditions there have been utilized as a basis, the
generalization has been extended to illustrate many basins.

margin and of coarse stony waste at their heads. Hence the val-
ley farms also extend over the edges of the fans, while only pas-
ture or dense chaparral occupies the upper portions. Finally

THE ANDES OF SOUTHERN PERU

there is the steep margin of the basin where the broad and moder-
ate slopes of the highland break do"\vn to the floor of the basin.

If a given basin lies at an elevation exceeding 14,000 feet
(4,270 m.), there will be no cultivation, only pasture. If at 10,000
or 11,000 feet (3,000 or 3,350 m.), there will be grain fields below

ZONE OF STORED PRECIPITATION

SOURCES OF BASIN STREAMS

ZONE OF CULTIVATION

^-LIMIT OF IRRIGATION AND--;
. INTENSIVE CULTIVATION

ZONE OF MOUNTAIN PASTURFS

Fig. 35 — Climatic cross-section showing the location of various zones of cultivation
and pasture in a typical intermont basin in the Peruvian Andes. The thickness of
the dark symbols on the right is proportional to the amount of each staple that is
produced at the corresponding elevation. See also the regional diagram Fig. 34.

and potato fields above (Figs. 34 and 35). If still lower, fruit will
come in and finally sugar cane and many other subtropical prod-
ucts, as at Abancay. Much will also depend upon the amount of
available water and the extent of the pasture land. Thus the
densely populated Cuzco basin has a vast mountain territory
tributary to it and is itself within the limits of barley and wheat
cultivation. Furthermore there are a number of smaller basins, like
the Anta basin on tlio nortli, which are dependent upon its better
markets and transportation facilities. A dominance of this kind
is self-stimulating and at last is out of all proportion to the
original fjiffcrencos of nature. Cuzco has also profited as the gate-
way to th(' great northeastern valley region of the Urubamba and
its big tributaries. All of tlie varied products of the subtropical
\alleys liiid tlicir irmiicdi.-ilc iiinrkct, at ( 'iizco.

Tlie effect of this natural conspiracy of conditions has been to
place i]\<- liistoric city of Cuzco in a position of extraordinary im-
portaiK'c. liinulrc'ds of years be^re the Spanish Conquest it was
a center of far-reaching influence, the home of the powerful Inca
kings. From it the strong arm of authority and conquest was ex-

THE COUNTRY OF THE SHEPHERDS 63

tended; to it came tribute of grain, wool, and gold. To one ac-
customed to look at such great consequences as having at least
some ultimate connection with the earth, the situation of Cuzco
would be expected to have some unique features. With the glori-
ous past of that city in mind, no one can climb to the surround-
ing heights and look down upon the fertile mountain-rimmed plain
as at an ordinary sight (Fig. 37). The secret of those great con^
quests lies not only in mind but in matter. If the rise of the Incas '
to power was not related to the topography and climate of the
Cuzco basin, at least it is certain that without so broad and noble ,
a stage the scenes would have been enacted on a far different?
scale.

The first Inca king and the Spanish after the Incas found here
no mobile nomadic tribes melting away at the first touch, no
savages hiding in forest fastnesses, but a well-rooted agricultural
race in whose center a large city had grown up. Without a city y
and a fertile tributary plain no strong system of government could
be maintained or could even arise. It is a great advantage in rul-
ing to have subjects that cannot move. The agricultural Indians /
of the Andean valleys and basins, in contrast to the mobile shep-
herd, are as fixed as the soil from which they draw their life.

The full occupation of the pasture lands about the Cuzco basin
is in direct relation to the advantages we have already enumer-
ated. Every part of the region feels the pressure of population. \
Nowhere else in the Peruvian Andes are the limits between cultiva-
tion and grazing more definitely drawn than here. Moreover,
there is today a marked difference between the types that inhabit
highland and basin. The basin Indian is either a debauched city
dweller or, as generally, a relatively alert farmer. The shepherds
are exceedingly ignorant and live for the most part in a manner
almost as primitive as at the time of the Conquest. They are shy f
and suspicious. Many of them prefer a life of isolation and rarely
go do^vn to the town. They live on the fringe of culture. The j.
new elements of their life have come to them solely by accident
and by what might be called a process of ethnic seepage. The
slight advances that have been made do not happen by design, they

64^ THE ANDES OF SOUTHERN PERU

merely happen. Put the highland shepherd in the basin and he
would starve in competition with the basin type. Undoubtedly he
would live in the basin if he could. He has not been driven out
\of the basin; he is kept out.

And thus it is around the border of the Abancay basin and
others like it. Only, the Abancay basin is lower and more varied
as to resources. The Indian is here in competition with the capi-
talistic white planter. He lives on the land by sufferance alone.
Farther up the slopes are the farms of the Indians and above
|,hem are the pastures of the ignorant shepherds. Whereas the
//Indian farmer who raises potatoes clings chiefly to the edge of
'^ The Cuzco basin where lie the most undesirable agricultural lands,
the Indian farmers of Abancay live on broad rolling slopes like
those near the pass northward toward Huancarama. They are
unusually prosperous, with fields so well cultivated and fenced,
so clean and productive, that they remind one somewhat of the
beautiful rolling prairies of Iowa.

It remains to consider the special topographic features of the
mountain environments we are discussing, in the Vilcapampa
region on the eastern border of the Andes (Fig. 36). The Cordil-
lera Vilcapampa is snow-crested, containing a number of fine
white peaks like Salcantay, Soray, and Soiroccocha (Fig. 140).
There are many small glaciers and a few that are several
miles long. There was here in glacial times a much larger system
of glaciers, wliicli lived long enough to work groat changes in the
topography. The floors of llic glaciated valleys were smoothed
and brondcned and their gradients flattened (Figs. 137 mid 190).
Tin- side walls wccc steepencMl and jji'ccipitous cirques were
formed a1 the xallcy heads. Also, Ihci'c were built across the val-
leys a number of stony morainic ridges. With all these changes
there was, however, biil liKlc ('(TccI u]um ilic main masses of the
liit,'- irifcr\;ill('v spurs. TIm'V i'ciii;iin as bcl'orc bold, \viii(l-K\v('])<,
l)rokcTi, and Ticaily inaccessible.

The work of llie glaciers aids flie mountain ]M'ople. Tlie stony
moraines afford lliein liandy sizable bnilding material for their
stone lints and lliejr numerous corrals. The thick tufts of grass

THE COUNTRY OF THE SHEPHERDS

Fig. 3G — Regional diagram for the Eastern Cordillera or Cordillera Vilcapampa.
Note the crowded zones on the right (east and north) in contrast to the open suc-
cession on the left. In sheltered places woodland extends even higher than shown.
At several points patches of it grow right under the snowline. Other patches grow
on the floors of the glaciated valley troughs.

in the marshy spots in the overdeepened parts of the valleys fur-

And, most im-

nish them with grass for their thatched roofs

66 THE ANDES OF SOUTHERN PERU

portant of all, the flat valley floors have the best pasture in the
whole mountain region. There is plenty of water. There is seclu-
sion, and, if a fence be built from one valley wall to another as can
be done with little labor, an entire section of the valley may be
inclosed. A village like Choquetira, located on a bench on the val-
ley side, commands an extensive view up and down the valley — an
important feature in a grazing village where the corrals cannot
always be built near the houses of the owners. Long, finger-like
belts of highland-shepherd population have thus been extended
into the mountain valleys. Sheep and llamas drift right up to
the snowline.

There is, however, a marked difference between the people on
opposite sides of the Cordillera Vilcapampa. On the west the moun-
tains are bordered by a broad highland devoted to grazing. On
the east there is a narrower grazing belt leading abruptly do^vn
to tropical valleys. The eastern or leeward side is also the
warmer and wetter side of the Cordillera. The snowline is sev-
eral hundred feet lower on the east. The result is that patches of
scrub and even a little woodland occur almost at the snowline in
favored places. Mist and storms are more frequent. The grass
is longer and fresher. Vegetation in general is more abundant.
The people make less of wool than of cattle, horses, and mules.
Vilcabamba pueblo is famous for its horses, wiry, long-haired lit-
tle boasts, as hardy as Shetland ponies. We found cattle grazing
only five hundred feet below the limit of perpetual snow. There
are cultivated spots only a little farther down, and only a thou-
sand feet below the snow are abandoned terraces. At the same
elevation are twisted quenigo trees, at least two hundred years
old, as shown by their rings of growth. Thus the limits of agricul-
ture are higher on the east; likewise the limits of cattle grazing
that Tint u rally goes with agriculture. Sheep would thrive, but
llamas do Ix-Hit in diici- count !-y, and Oic slicplicrd must needs
mix liis flocks, for llic wool wliicli is his cliicf product requires
tranHi)ortation and only the cheap and acclimated llama is at the
shepherd's disposMl. From these facts it will be seen that the
anthropo-geographic contrasts between the eastern ;md western

Fig. 37.

^.y*:"! "Ti,"::';" ^^-.v,-*-,*

'<-«£,'«.■; ,»■.

Fig. 38.

Fig. 37 — Cuzco and a portion of the famous Cuzco basin with bordering grassy
highlands.

Fig. 38 — Terraced valley slopes and floor, Urubamba Valley between Urubamba
and Ollantavtambo.

.rf-*4.'

Kk;. 1(1.

Fl(J. 39 — lluicliiliiiii, iii'iir ('limiiiilKiiiihilla, ;i lypiciil iiKMiiitiiiii vill:ig<', in the
vnllpyH of tlu' Ccntrnl HnngcH, PiTuvimi AdcU'b.

Fio. 40 — I'otnto field iihovc Vilciiimmlm at 12.000 f«'ft (.J.OOO m.). The natural
Bod iH hrokon by n Htc«-l-«hod Mticl< iiikI Ihc Hccd potato dropped into a mere puncture.
It rcceiv«'H no iitleiitinn tln'iijiftcr iinlil liiirvcst. time.

THE COUNTRY OF THE SHEPHERDS 67

sides of the Cordillera Vilcapampa are as definite as the climatic
and vegetal contrasts. This is especially well shown in the differ-
ences between dry Arma, deep-sunk in a glaciated valley west of
the crest of the mountains, and wet Puquiura, a half-day's journey
east of the crest. There is no group on the east at all comparable
to the shepherds of Choquetira, either in the matter of thorough-
going dependence upon grazing or in that of dependence upon
glacial topography.

Topography is not always so intimately related to the life of
the people as here. In our own country the distribution of avail-
able water is a far greater factor. The Peruvian Andes therefore
occupy a distinctive place in geography, since, more nearly than
in most mountains, their physical conditions have typical human
relations that enable one clearly to distinguish the limits of con-
trol of each feature of climate or relief.

CHAPTER VI

THE BORDER VALLEYS OF THE EASTERN ANDES

Ox the northeastern border of the Peruvian Andes long moun-
tain spurs trail down from the regions of snow to the forested
plains of the Amazon. Here are the greatest contrasts in the

physical and human geog-
raphy of the Andean Cordil-
lera. So striking is the fact
that every serious student
of Peru finds himself com-
pelled to cross and recross
this natural frontier. The
thread of an investigation
runs irregularly now into
one border zone, now into
another. Out of the forest
came the fierce marauders
who in the early period
drove back the Inca pioneers.
Down into the forest to
escape from the Spaniards

Fio. 41— Regional diagram of the eastern Aed tllO last luca ail(l his
aspect of the Cortlillera Vilcapainpa. See also fu<^itive COlU't Here the

Fit'. 17 of wliieh tliis is an cnhxrged section.

Jesuit fathers sowed their
missions along the forest margin, and watched over them for
two liundrcd years. From tlio mountain border one rubber
project after jinotlier lias been launched into the vast swampy
lowlands 11ire;i(|c(l liy yreat rivers. As ;in elliiiic boundary
^the eastern niounl.-iin hoi-dei- of i'ci'u ;iiid Pxjlixi.M has no e(|ual
elsewliere in Sonlli A nici-iea. P'roni the earliest antifjuity tlu;
tribes of the grass-covered mountains and the hordes of the for-
ested jjlains have had strongly divergent customs and speech, that
bred enduring liafced and led 1o fi-e(|ncnt and bloody strife.

Fig. 42 — Rug weaver at Cotahiiasi. The industry is limited to a small group of
related families, living in the Cotahuasi Canyon near Cotahuasi. Tlie rugs are made
of alpaca wool. Pure black, pure white, and various shades of mixed gray wool are
employed. The result is that the rugs have " fast " colors that always retain their
original contrasts. They are made only to order at the homes of the purchasers. The
money payment is small. Init tn it is added board and lodging, besides tobacco, liqueurs,
and wine. Before drinking tlicv diji their finger-tips in the wine and sprinkle the
earth " that it may be fruitful,'' the air " that it may be warm," the rug " that it may
turn out well," and finally themselves, making the sign of the cross. Then they set
to work.

THE BORDER VALLEYS OF THE EASTERN ANDES 69

On the steepest spurs of the Pampaconas Valley the traveler
may go from snow to pasture in a half day and from pasture to
forest in the same time. Another day he is in the hot zone of the
larger valley floors, the home of the Machigangas. The steep
descents bring out the superimposed zones with diagrammatic
simplicity. The timber line is as sharply marked as the edge of a
cultivated field. At a point just beyond the huts of Pampaconas
one may stand on a grassy spur that leads directly up — a day's
journey — to the white summits of the Cordillera Vilcapampa.
Yet so near him is the edge of the forest that he is tempted to
try to throw a stone into it. In an hour a bitter wind from the
mountains may drive him to shelter or a cold fog come rolling up
from the moist region below. It is hard to believe that oppressive
heat is felt in the valley just beneath him.

In the larger valleys the geographic contrasts are less sharp
and the transition from mountains to plain, though less spectacu-
lar, is much more complex and scientifically interesting. The for-
est types interfinger along the shady and the sunny slopes. The
climate is so varied that the forest takes on a diversified character
that makes it far more useful to man. The forest Indians and
the valley planters are in closer association. There are many
islands and peninsulas of plateau population on the valley floor.
Here the zones of climate and the belts of fertile soil have larger
areas and the land therefore has greater economic value. Much
as the valley people need easier and cheaper communication with
the rest of Peru it is no exaggeration to say that the valley prod-
ucts are needed far more by the coast and plateau peoples to
make the republic self-supporting. Coca, wood, sugar, fruit, are
in such demand that their laborious • and costly transportation
from the valleys to the plateau is now carried on with at least
some profit to the valley people. Improved transportation would
promote travel and friendship and supply a basis for greater
political unity.

A change in these conditions is imminent. Years ago the
Peruvian government decreed the construction of a railway from
€uzco to Santa Ana and preliminary surveys were made but with-

70 THE ANDES OF SOUTHERN PERU

out any immediate practical effect. By June, 1914, 12.4 miles (20
km.) had been opened to traffic. The total length of the proposed
line is 112 miles (180 km.), the gauge is to be only 2.46 feet
(75 cm.),' and the proposed cost several millions of dollars. The
financial problem may be solved either by a diversion of local
revenues, derived from taxes on coca and alcohol, or by borrowed
foreign capital guaranteed by local revenues.

A shrubby vegetation is scattered along the valley from the
village of Urubamba, 12,000 feet (3,058 m.) above sea level, to the
Canyon of Torontoy. It is local and of little value. Trees appear
at Ollantaytambo, 11,000 feet (3,353 m.), and here too are more
extensive wheat and maize fields besides throngs of cacti aiKl
great patches of wild geraniums. On our valley journey we
camped in pleasant fields flanked by steep hills whose summits
each morning were tipped with snow. Enormous alluvial fans
have partly filled up the valleys and furnished broad tracts of
fertile soil. The patient farmers have cleared away the stones on
the flatter portions and built retaining walls for the smooth fields
required for irrigation. In places the lower valley slopes are ter-
raced in the most regular manner (Fig. 38). Some of the fans are
too steep and stony for cultivation, exposing bare tracts which
wash down and cover the fields. Here and there are stone walls
built especially to retain the rush of mud and stones that the rains
bring down. Many of them were overtlirown or completely
1)11 il'd. Unless the stream channels on Ihe fans are carefully
watched and effective works kept u]), the labor of years may be
destroyed in a single slide from the head of a steep fan.
/ Each group of fans has a population proportioned to its size
4ii<l fertility. If there are broad expanses a town like Urubamba
or a groat hacienda like I lii.-i(l(|uirin is sure lo be found. One
grou)) of iiugc stony fans below Unib.inili.-i (l-'ig. 180) has only
a lliiii ])oiinlati<»n, for ilie soil is coarse and infer! ile and 11i(> rivers
deeply inlrenclied. In some jilaees llie tiny fans perclied high
upon the flanks of the mountains where; little tributaries burst out

• Dnilv foiiR. nnd Trndf T'vcpoii, .Iunc 10, 1011, No. Kif), niul f'ommcrfc l?cportH,
March 20. I'oc, V,, rw;

THE BORDER VALLEYS OF THE EASTERN ANDES 71

of steep ravines are cultivated by distant owners who also till
parts of the larger fans on the main valley floors. Between the
fans of the valley bottoms and the smooth slopes of the high
plateaus are the unoccupied lands — the steep canyon walls. Only
in the most highly favored places where a small bench or a patch
of alluvium occurs may one find even an isolated dwelling. The
stair-like trails, in some places cut in solid rock, zigzag up the
rocky slopes. An ascent of a thousand feet requires about an
hour's travel with fresh beasts. The valley people are therefore
"walled in. If they travel it is surely not for pleasure. Even busi-
ness trips are reduced to the smallest number. The prosperity
and happiness of the valley people are as well known among the
plateau people as is their remarkable bread. Their climate has a
combination of winter rain and winter cold with light frosts that
is as favorable for good wheat as the continuous Avinter cold and
snow cover of our northern Middle West. The colder grainfields
of the plateau are sowed to barley chiefly, though there is also
produced some wheat. Urubamba wheat and bread are exported
in relatively large quantities, and the market demands greater
quantities than the valley can supply. Oregon and Washington
flour are imported at Cuzco, two days' muleback journey from the
wheat fields of Urubamba.

Such are the conditions in the upper Urubamba Valley. The
lower valley, beginning at Huadquiila, is 8,000 feet (2,440 m.)
above sea level and extends down to the two-thousand-foot con-
tour at Rosalina and to one thousand feet (305 m.) at Pongo de
Mainique. The upper and lower sections are only a score of miles
(30 km.) apart between Huadquina and Torontoy, but there is a
difference in elevation of three thousand feet (915 m.) at just the
level where the maximum contrasts are produced. The cold tim-
ber line is at 10,500 feet (3,200 m.).- Winter frosts arc common

^ Reference to the figures in this chapter will show great variation in the level
of the timber line depending upon insolation as controlled by slope exposure and
upon moisture directly as controlled largely by exposure to winds. In some places
these controls counteract each other; in other places they promote each other's
effects. The topographic and climatic cross-sections and regional diagrams else-
where in this book also emphasize the patchiness of much of the woodland and scrub,
some noteworthy examples occurring in the chapter on the Eastern Andes. Two of

72 THE ANDES OF SOUTHERN PERU

at the one place; they are absent altogether at the other. Toroutoy
produces corn; Huadquiua produces sugar cane.

These contrasts are still further emphasized by the sharp topo-
graphic break between the two unlike portions of the valley. A
few miles below Torontoy the Urubamba plunges into a mile-deep
granite canyon. The walls are so close together that it is impos-
sible from the canyon floor to get into one photograph the highest
and steepest walls. At one place there is over a mile of descent
in a horizontal distance of 2,000 feet. Huge granite slabs fall off
along joint planes inclined but 15° from the vertical. The effect
is stupendous. The canyon floor is littered with coarse waste and
the gradient of the river greatly steepened. There is no cultiva-
tion. The trees cling with difficulty to patches of rock waste or
to the less-inclined slopes. There is a thin crevice vegetation that
outlines the joint pattern where seepage supplies the venturesome
roots ^^ith moisture. Man has no foothold here, save at the top
of the country, as at Machu Picchu, a typical fortress location
safeguarded by the virtually inaccessible canyon wall and con-
nected with the main ridge slopes only by an easily guarded
narrow spur. Toward the lower end of the canyon a little
finer alluvium appears and settlement begins. Finally, after
a tumble of three thousand feet over countless rapids the river
emerges at Colpani, where an enormous mass of alluvium has
been dumped. The well-intrenched river has already cut a
lai'L'"!' i)art of it away. A little farther on is Huadquina in
the Salcantay Valley, whore a tributary of the Urubamba has
built up a sheet of alluvial land, bright green witli cane. From
the distant peaks of Salcantay and its neighbors well-fed streams
descend to fill the irrigation channels. Thus the snow and rock-
waste ()\' the (lislaul iixiunlaiTis ai'c iiinicd into corn and sugar on
the valley lowlands.

the moBt rpmnrkablp caflPB nr<> the pntrh of wnodlnnd nt 14,500 fc«'t (4,420 m.) just
undfr tho hnnf^nf; plnricr of Soirocroclia luifl tlic otln-r tho qneniKo Hcrnl> on the
lav.i pliifrnu nbovo riiut|iiihnmhii nt 13.000 fcot (3,900 m.). The strong compression
of climntin zonen in the rnihntnha Vnlh-y l)oln\v S.uita Ana brijiRs into sharp contrast
the RrnsHV ridf^n slope's fjicirif? the huh jiikI i\\v forested slopes that liave a high propor-
tion of H)ind<'. Fig. r)4 r^prcsints the general distribution but the details jire far
more complicated. Sec also Figs. 53A and 53B. (See Coropuna Quadrangle.)

■-mr-

^jmr

I'll,

Fig. 44 — The snow-capped Cordillera Vilcapaiupa north of Yucay and the upper
canyon of the Urubamba from tlie wheat fields near Chinchero. In the foreground
is one of the well-graded mature slojjes of Fig. 123. The crests of the mountains lie
along the axis of a granite intrusion. The extent of the snowtields is extraordinary
in view of the low latitude, 13° S.

Fig. 45 — Rounded slopes due to glacial action at Panipaconns in the Pampaconas
Valley near Vilcabamba. A heavy tropical forest extends up the Pampaconas \'alley
to the hill slopes in the background. Its upper limit of growth is about 10,000 feet
(3,050 m.). The camera is pointed slightly downhill.

"5 to

:t. '^

•^ H

THE BORDER VALLEYS OF THE EASTERN ANDES 73

The Cordillera Vilcapampa is a climatic as well as a topo-
graphic barrier. The southwestern aspect is dry; the northeast-
ern aspect forested. The gap of the canyon, it should be noticed,
comes at a critical level, for it falls just above the upper border
of the zone of maximum precipitation. The result is that though
mists are driven through the canyon by prolonged up-valley
winds, they scatter on reaching the plateau or gather high up on
the flanks of the valley or around the snowy peaks overlooking
the trail between Ollantaytambo and Urubamba. The canyon
walls are drenched with rains and even some of the lofty spurs
are clothed with dense forest or scrub.

Farther down the valley winds about irregularly, now pushed
to one side by a huge alluvial fan, now turned by some resistant-
spur of rock. Between the front range of the Andes and the
Cordillera Vilcapampa there is a broad stretch of mountain coun-
try in the lee of the front range which rises to 7,000 feet (2,134 m.)
at Abra Tocate (Fig. 15), and falls off to low hills about Bosalina.
It is all very rough in that there are nowhere any flats except for
the narrow playa strips along the streams. The dense forest adds
to the difficulty of movement. In general appearance it is very
much like the rugged Cascade country of Oregon except that the
Peruvian forest is much more patchy and its trees are in many
places loaded with dense dripping moss which gives the landscape
a somber touch quite absent from most of the forests of ihe
temperate zone. ^

The fertility of the eastern valleys of Peru — the result of a
union of favorable climate and alluvial soil — has drawn the
planter into this remote section of the country, but how can he dis-
pose of his products? Even today with a railway to Cuzco from
the coast it is almost impossible for him to get his sugar and cacao
to the outside world.^ How did he manage before even this rail-
way was built? How could the eastern valley planter live before
there were any railways at all in Peru? In part he has solved
the problem as the moonshiner of Kentucky tried to solve it, and

• Commenting on the excellt nee of the cacao of the niontaua of the Urubamba
von Tsehudi remarked (op. cit., p. 37) that the long land transport prevented its usii
in Lima where the product on the market is that imported from Guayaquil.

74. THE ANDES OF SOUTHERN PERU

from cane juice makes aguardiente (brandy). The latter is a
much more valuable product than sugar, hence (1) it will bear a
higher rate of transportation, or (2) it will at the same rate of
transportation yield a greater net profit. In a remote valley
where sugar could not be exported on account of high freight
rates brandy could still be profitably ex^Dorted.

The same may be said for coca and cacao. They are condensed
and valuable products. Both require more labor than sugar but
are lighter in bulk and thus have to bear, in proportion to their
value, a smaller share of the cost of transportation. At the end
of three years coca produces over a ton of leaves per acre per
year, and it can be made to produce as much as two tons to the
acre. The leaves are picked four times a year. They are worth
from eight to twelve cents gold a pound at the plantation or six-
teen cents a pound at Cuzco. An orchard of well-cultivated and
irrigated cacao trees will do even better. Once they begin to bear
the trees require relatively little care except in keeping out weeds
and brush and maintaining the water ditches. However, the pods
must be gathered at just the right time, the seeds must be raked
and dried with expert care, and after that comes the arduous
labor of the grinding. This is done by hand on an inclined plane
with a heavy round stone whose corners fit the hand. The choco-
late must then be worked into cakes and dried, or it must be
sacked in heavy cowhide and sewed so as to be practically air
tiglit. AVlion eight or ten years old the trees are mature and each
may then bear a thousand pounds of seed.

Tf labor were cheap and abundant the whole trend of tropical
agriculture in the eastern Valleys would be toward intensive culti-
vation and the production of expensive exports. But labor is ac-
1u;illy scarce. Every ])lan<er must have agents wlio can send men
down from llic jjlafcan lowiis. And llio jilanter himself must use
his 1;il»or to flic best ad\an1age. Aguardiente 7'ef|uires less labor
than cacao and coca. The cane costs about as much in labor the
first year as the coca ])ush or the cacao tree, but after that much
less. Tlio manufacture of brandy from tlie cane juice requires lit-
tle la))or though much expensive niacliiiiery. For chocolate, a

-#;^'^-^^ '

Mik^W'i

n -si

ii: ■ = i "2

■^ s o

— :: t; p

g o - - a

w^: - ^ . .1 ^ ^ =^

-. "S cT •- — rf -
«BS* ■« "S ^ - -S 1 ao

o r - ^ "tr —

i^ .^ ^ "i ? ; - ;:.

2 ^H 5 ;:s ^ =

,hi<^

-^ rt .2

^ O

-»->

'-S

«*-!

-tJ

-i->

"E,

.s°

^ ^ ^ to
? ^

hn cS a> y

■-■

-M

."ti

'-'

"E,

■"3

>^.

-a

Ira

f»j

<<-i

-tJ

h-t

(^
c

'O (B O g

2 ^

be
^ 2

THE BORDER VALLEYS OF THE EASTERN ANDES 75

storehouse, a grinding stone, and a rake are all that are required.
So the planter must work out his own salvation individually. He
must take account of the return upon investments in machinery,
of the number of hands he can command from among the "faena"
or free Indians, of the cost and number of imported hands from
the valley and plateau towns, and, finally, of the transportation
rates dependent upon the number of mules in the neighborhood,
and distance from the market. If in addition the labor is skilfully
employed so as to have the tasks which the various products re-
quire fall at different periods of the year, then the planter may
expect to make money upon his time and get a return upon his
initial investment in the land.*

The type of tropical agriculture which we have outlined is
profitable for the few planters who make up the white population
of the valleys, but it has a deplorable effect upon the Indian popu-
lation. Though the planters, one and all, complain bitterly of the
drunken habits of their laborers, they themselves put into the
hands of the Indians the means of debauchery. Practically the
whole production of the eastern valleys is consumed in Peru.
What the valleys do not take is sent to the plateau, where it is the
chief cause of vicious conduct. Two-thirds of the prisoners in the
city jails are drunkards, and, to be quite plain, they are virtually
supplied with brandy by the planter, who could not otherwise
make enough money. So although the planter wants more and
better labor he is destroying the quality of the little there is, and,
if not actually reducing the quantity of it, he is at least very cer-
tainly reducing the rate of increase.

The difficulties of the valley planter could be at least partly
overcome in several ways. The railway will reduce transporta-
tion costs, especially when the playas of the valleys are all
cleared and the exports increased. Moreover the eastern valleys

* The inadequacy of the labor supply was a serious obstacle in the early days
as well as now. In the documents pertaining to the " Obispados y Audiencia del
Cuzco" (Vol. 11, p. 349 of the " Juicio dc Lfmites entre el PerG y Bolivia, Prueba
Peruana presentada al Gobierno de la Ropfiblica Argentina por Victor M. Maurtua."
Barcelona, 1906) we find the report that the natives of the curacy of Ollantaytambo
who came down from the hills to Huadquina to hear mass were detained and compelled
to give a day's service on the valley plantations under pain of chastisement.

76 THE ANDES OF SOUTHERN PERU

are capable of producing things of greater utility than brandy
and coca leaves. So far as profits are increased by cheaper trans-
portation we may expect the planter to produce more rather than
less of brandy and coca, his two most profitable exports, unless
other products can be found that are still more profitable. The
ratio of profits on sugar and brandy will still be the same unless
the government increases the tax on brandy until it becomes no
more profitable than sugar. That is what ought to be done for
the good of the Indian population. It cannot be done safely with-
out offering in its place the boon of cheaper railway transporta-
tion for the sugar crop. Furthermore, with railway improve-
ments should go the blessings that agricultural experiments can
bestow. A government farm in a suitable place would establish
rice and cotton cultivation. :\rany of the playas or lower alluvial
lands along the rivers can be irrigated. Only a small fraction of
the water of the Rio Urubamba is now turned out upon the fields.
For a large part of the year the natural rainfall would suffice to
keep rice in good condition. Six tons a year are now grown on
Hacienda Sahuayaco for local use on account of the heavy rate
on rice imported on muleback from Cuzco, whither it comes by
sea and by trail from distant coastal valleys. The lowland people
also need rice and it could be sent to them do^^^l river by an easier
route than that over which their supplies now come. It should be
exported to the highlands, not imported therefrom. There are so
many varieties adapted to so many kinds of soil and climate that
large amounts should be produced at fair profits.

The cotton plant, on the other hand, is more particular about
climato and especially the duration of dry and wet seasons; in
spite of this its requirements are all met in the Santa Ana Valley.
The i-niiifnll is mod'Talc ;md there is an abundance of dry warm
soil. Tlif ))laii1 f'<ml(l make most of ils growlli in llie wet season,
and Hie four iiioiitlis of cooler dry season with only occasional
shower.s would favor Ixitli a briglit staple and a good picking sea-
son. More labor would be ref|uire<1 I'ot- cotton and rice and for
the increased production of cacao than under the present system.
This would not be a real difTiculty if the existing labor supply

THE BORDER VALLEYS OF THE EASTERN ANDES 77

were conserved by the practical abolition, through heavy taxation,
of the brandy that is the chief cause of the laborer's vicious habits.
This is the first step in securing the best return upon the capital
invested in a railway. Economic progress is here bound up with
a very practical morality. Colonization in the eastern valleys, of
which there have been but a few dismal attempts, will only extend
the field of influence, it will not solve the real problem of bringing
the people of the rich eastern territory of Peru into full and
honorable possession of their natural wealth. .

The value of the eastern valleys was kno\vii in Inca times, for
their stone-faced terraces and coca-drying patios may still be seen
at Echarati and on the border of the Chaupimayu Valley at
Sahuayaco. Tradition has it that here were the imperial coca
lands, that such of the forest Indians as were enslaved were
obliged to work upon them, and that the leaves were sent to Cuzco
over a paved road now covered with "montafia" or forest. The-
Indians still relate that at times a mysterious, wavering, white
light appears on the terraces and hills where old treasure lies
buried. Some of the Indians have gold and silver objects which
they say were dug from the floors of hill caves. There appears to
have been an early occupation of the best lands by the Spaniards,
for the long extensions do'^Ti them of Quechua population upon
which the conquerors could depend no doubt combined with the
special products of the valley to draw w^hite colonists thither.'^

" The Spanish occupation of the eastern valleys was early and extensive. Im-
mediately after, the capture of the young Inca Tupac Amaru and the final subjugation
of the province of Vilcapampa colonists started the cultivation of coca and cane.
Development of the main Urubamba Valley and tributary valleys proceeded at a good
rate: so also did their troubles. Baltasar de Ocampo writing in 1610 (Account of the
Province of Vilcapampa, Hakluyt Soc. Pubis., Ser. 2, Vol. 22. 1907, pp. 20.3-247) relates
the occurrence of a general uprising of the negroes employed on the sugar plantations
of the region. But the peace and prosperity of every place on the eastern frontier was
unstable and quite generally the later eighteenth and earlier nineteenth centuries saw
a retreat of the border of civilization. The native rebellion of the mid-eighteenth
century in the montana of Chanchamayo caused entire abandonment of a previously
flourishing area. When Raimondi wrote in 1885 (La Montana de Chanchamayo, Lima,
1885) some of the ancient hacienda sites were still occupied by savages. In the
Paucartambo valleys, settlement began by the end of the sixteenth century and at the
beginning of the nineteenth before their complete desolation by the savages they were
highly prosperous. Paucartambo town, itself, once important for its commerce in coca
is now in a sadly decadent condition.

78 THE ANDES OF SOUTHERN PERU

General Miller,"^ writing in 1836, mentions tlie villages of Incbarate
(Ecliarati) and Sant' Ana (Santa Ana) but discourages tbe
idea of colonization "... since tbe river . . . bas lofty moun-
tains on eitber side of it, and is not navigable even for boats."

In tbe ''Itinerario de los viajes de Raimondi en el Peru" ' tbere
is an interesting account of tbe settlement by tbe Rueda family
of tbe great estate still beld by a Rueda, tbe wife of Sefior Duque.
Jose Rueda, in 1829, was a government deputy representative and
took bis pay in land, acquiring valuable territory on wbicb tbere
was notbing more tban a mission. In 1830 Rueda ceded certain
lands in ''arriendo" (rent) and on tbese were founded tbe haci-
endas Pucamoco, Sabuayaco, etc.

Sefior Gonzales, tbe present owner of Hacienda Sabuayaco, re-
cently obtained bis land — a princely estate, ten miles by forty —
for 12,000 soles ($6,000). In a few years be bas cleared tbe best
tract, built several miles of canals, bewed out houses and furni-
ture, planted coca, cacao, cane, coffee, rice, pepper, and cotton,
and would not sell for $50,000. Moreover, instead of being a
superintendent on a neigbboring estate and keeping a shop
in Cuzco, wbere bis large family was a source of great ex-
pense, be bas become a wealthy lando^\^ler. He bas educated a
son in the United States. He is importing machinery, such as a
rice thresher and Ji distilling plant. His son is looking forward
to tbe piiiebase of still more playa land down river. He pays a
sol a day to each laborer, securing men from Cotabambas and
Al)ancay, whore there are many Indians, a low standard of wages,
little unoccupied laud, aud a hot climate, so that tbe immigrants
do not need to become acclimatized.

Tlie deepest valleys in tiic I'L-istei'ii Andes of Peru have a
semi ;i?-i<i diiii.-ile wliicli brings in its ti'niii ;i wu-iety of unusual
geogr.'iplile i-cl;iti()iis. Af (ii-st. as one descends tbe \\Mlley the
sli;i(ly ;\]\(\ sniiiiy slopes sliow sharply eoiit i-asted vegetation.

• Nfttirn of a .Innrncy to Hie Xorlhward iiiid nlHO to the Eastward of Cnzcn, nnd
amoii^ til*' (;lniriHio» Indinnn, in .Inly, IH.'jn. .Foiirii. l^)y.■^l Clrog. See, \'ol. (>, 1836,
pp. 174-1 HO.

' Hoi. Soc. (;pog. do Miiiii, \<d. 8, 1898, j). 45.

Fig. 51.

Fig. 52.

Fig. 51 — Robledo's mountain-side trail in the Uriibamba Valley below Rosalina.

Fig. 52 — An epiphyte partly supported by a dead host at Ro-alina, elevation 2.000
feet. The epiphyte bears a striking resemblance to a horned beast whose arched back,
tightly clasped fingers, and small eyes give it a peculiarly malignant and life-like
expression.

Fig. 53A.

Fl(i. :^'L\—'J'1k' smooth i^runny hlopcs at (li<' jimctioTi of the 'SMiiMtili (left) i\u(\
rnihamba (ri^lil) rivcTH near I'lihcllon.

Fio. ').'{U — iJi.Htiihiitioii <if vc'f,'cljition in the rnil»iiinl)ii \ nllry ii(;ir Torontoy. 'Ilic
patchcH of timber in the liaekgrownd occii|)y Oic Hhady hiden ot the spiiiH; the sunny
slopes ar" graHH-covered ; llx- vallry (loop i^ (illcl with thick. -Is iiiid pntchcs of wood-
land but not true forest.

THE BORDER VALLEYS OF THE EASTERN ANDES 79

The one is forested, the other grass-cov-.
ered. Slopes that receive the noon and \
afternoon sun the greater part of the year
are hottest and therefore driest. For
places in 11° south latitude the sun is well
to the north six months of the year, nearly
overhead for about two months, and to the
south four months. Northwesterly as-
pects are therefore driest and warmest,
hence also grass-covered. In many places
the line between grass and forest is de-
veloped so sharply that it seems to be the
artificial edge of a cut-over tract. This is
true especially if the relief is steep and
the hill or ridge-crests sharp.^

At Santa Ana this feature is developed
in an amazingly clear manner, and it is
also combined with the dry timber line and
with producti\dty in a way I have never
seen equaled elsewhere. The diagram will
explain the relation. It will be seen that
the front range of the mountains is high
enough to shut off a great deal of rainfall.
The lower hills and ridges just within the
front range are relatively dry. The deep
valleys are much drier. Each broad ex-
pansion of a deep valley is therefore a dry
pocket. Into it the sun pours even when

* Marcoy who traveled in Peru in the middle of the
last century was greatly impressed by the sympathetic
changes of aspect and topography and vegetation in the
eastern valleys. He thus describes a sudden change of
scene in the Occobamba valley: ". . . the trees had dis-
appeared, the birds had taken wing, and great sandy
spaces, covered with the latest deposits of the river, al-
ternated with stretches of yellow grass and masses of
rock half-buried in the ground." (Travels in South
America, translated by Elihu Rich, 2 vols. jSTew York,
1875, Vol. 1, p. 326.)

80 THE ANDES OF SOUTHERN PERU

all the surrounding hills and mountains are wrapped in cloud.
The greater number of hours of sunshine hastens the rate of
evaporation and still further increases the dryness. Under the
spur of much sunlight and of ample irrigation water from the
wetter hill slopes, the dry valley pockets produce huge crops of
fruit and cane.

The influence of the local climate upon tree growth is striking.
Every few days, even in the relatively dry winter season, clouds
gather about the hills and there are local showers. The lower
limit of the zone of clouds is sharply marked and at both Santa
Ana and Echarati it is strikingly constant in elevation — about
five thousand feet above sea level. From the upper mountains
the forest descends, with only small patches of glade and prairie.
At the lower edge of the zone of cloud it stops abruptly on the
warmer and drier slopes that face the afternoon sun and continues
on the moister slopes that face the forenoon sun or that slope
away from the sun.

But this is not the only response the vegetation makes. The
forest changes in character as well as in distribution. The forest
in the wet zone is dense and the undergrowth luxuriant. In the
selective slope forest below the zone of cloud the undergrowth is
commonly thin or wanting and the trees grow in rather even-aged
stands and by species. Finally, on the valley floor and the tribu-
tary fans, there is a distinct growth of scrub with bands of trees
along the water courses. Local tracts of coarse soil, or less rain
on account of a deep "hole" in a valley surrounded by steeper
and higher mountains, or a change in the valley trend that brings
it into less free communication with the prevailing winds, may
still further increase the dryness and bring in a true xerophytic
or drought-resisting vegetation. Cacti are common all llirough
the Santa Ana Valley and below Sahuayaco there is a patch of
tree cacti and similar forms several square miles in extent. Still
farther down and al)out half-way between Sahuayaco and Pabol-
lon are immense tracts of grass-covered mountain slopes (Fig.
53). Those extend beyond Kosalina, the last of them terminating
near A bra Tocate (Fig. IT)). The sudden interruption is due to a

THE BORDER VALLEYS OF THE EASTERN ANDES 81

turn in the valley giving freer access to the up-valley winds that
sweep through the pass at Pongo de Mainique.

Northward from Abra Tocate (Fig. 55) the forest is prac-
tically continuous. The break between the two vegetal regions
is emphasized by a corral for cattle and mules, the last
outpost of the plateau
herdsmen. Not three
miles away, on the oppo-
site forested slope of the
valley, is the first of the
Indian clearings where
several families of Machi-
gangas spend the wet sea-
son when the lower river
is in flood (Fig. 21). The
grass lands will not yield
corn and coca because the
soil is too thin, infertile,
and dry. The Indian
farms are therefore all in
the forest and begin al-
most at its very edge.
Here finally terminates a
long peninsula of grass-
covered country. Below this point the heat and humidity rapidly
increase; the rains are heavier and more frequent; the country
becomes almost uninhabitable for stock; transportation rates
double. Here is the undisputed realm of the forest with new kinds
of trees and products and a distinctive type of forest-dwelling
Indian.

At the next low' pass is the skull of an Italian who had mur-
dered his companions and stolen a season's picking of rubber, at-
tempting to escape by canoe to the lower Urubamba from the
Pongo de Mainique. The Machigangas overtook him in their
swiftest dugouts, spent a night with him, and the next morning
shot him in the back and returned with their rightful property —

Fig. 55 — Map to shoAV the relation of the
grasslands of the dry lower portion of the
Urubamba Valley (unshaded) to the forested
lands at higher elevations (shaded). See Fig.
54 for climatic conditions. Patches and slender
tongues of woodland occur below the main
timber line and patches of grassland above it.

82 THE ANDES OF SOUTHERN PERU

a harvest of rubber. For more than a decade foreigners have been
coming doAvn from the plateau to exploit them. They are an inde-
pendent and free tribe and have simple yet correct ideas of right
and wrong. Their chief, a man of great strength of character
and one of the most likeable men I have known, told me that he
placed the skull in the pass to warn away the whites who came to
rob honest Indians.

The Santa Ana Valley between the Canyon of Torontoy and
the hea^'y forest belt below Eosalina is typical of many of the
eastern valleys of Peru, both in its physical setting and in its
economic and labor systems. Westward are the outliers of the
Vilcapampa range; on the east are the smaller ranges that front
the tropical lowlands. Steep valleys descend from the higher
country to join the main valley and at the mouth of every tribu-
tary is an alluvial fan. If the alluvium is coarse and steeply in-
clined there is only pasture on it or a growth of scrub. If fine and
broad it is cleared and tilled. The sugar plantations begin at
Huadquifia and end at Eosalina. Those of Santa Ana and
Echarati are the most productive. It takes eighteen months for
the cane to mature in the cooler weather at Huadquifia (8,000 feet).
Less than a year is required at Santa Ana (3,400 feet). Patches
of alluvium or playas, as they are locally called, continue as far
as Santo Anato, but they are cultivated only as far as Eosalina.
The last large plantation is Pabellon ; the largest of all is Echarati.
All are irrigated. In the wet months, December to March inclu-
sive, there is little or no irrigation. In the four months of the dry
season, June to September inclusive, there is frequent irrigation.
Since the cane matures in about ten months the harvest seasons
fall irregularly with respect to the seasons of rain. Therefore the
land is cleared and planted at irregular intervals and labor dis-
tributed soincwlial Ilii-oiiL-li llic year. There is however a concen-
tration of ];il)()r 1 own 1(1 llif end of the dry season when most of
the caTK' is cut for griudiug.

Tho combiiu'd freight rate and government tax on coca, sugar,
and ])randy take a large part of all that the planter can get for
his crop. It is 120 miles (190 km.) from Santa Ana to Cnzco and

THE BORDER VALLEYS OF THE EASTERN ANDES 83

it takes five days to make the journey. The freight rate on coca
and sugar for mule carriage, the only kind to be had, is two cents
per pound. The national tax is one cent per pound (0.45 kg.).
The coca sells for twenty cents a pound. The cost of production
is unknown, but the paid labor takes probably one-half this
amount. The planter's time, capital, and profit must come out
of the rest. On brandy there is a national tax of seven cents per
liter (0.26 gallon) and a municipal tax of two and a half cents.
It costs five cents a liter for transport to Cuzco. The total in
taxes and transport is fourteen and a half cents a liter. It sells
for twenty cents a liter. Since brandy (aguardiente), cacao (for
chocolate), and coca leaves (for cocaine) are the only precious sub-
stances which the valleys produce it takes but a moment's inspec-
tion to see how onerous these taxes would be to the planter if
labor did not, as usual, pay the penalty.

Much of the labor on the plantations is free of cost to the
owner and is done by the so-called faena or free Indians. These
are Quechuas who have built their cabins on the hill lands
of the planters, or on the floors of the smaller valleys. The dis-
position of their fields in relation to the valley plantations is full
of geographic interest. Each plantation runs at right angles to
the course of the valley. Hacienda Sahuayaco is ten miles (16
km.) in extent down valley and forty miles (64 km.) from end to
end across the valley, and it is one of the smaller plantations ! It
follows that about ten square miles lie on the valley floor and half
of this can ultimately be planted. The remaining three hundred
and ninety square miles include some mountain country with pos-
sible stores of mineral wealth, and a great deal of ''fells" coun-
try — grassy slopes, graded though steep, excellent for pasture,
with here and there patches of arable land. But the hill country
can be cultivated only by the small farmer who supplements his
supply of food from cultivated plants like potatoes, corn, and
vegetables, by keeping cattle, mules, pigs, and poultry, and by
raising coca and fruit.

The Indian does not own any of the land he tills. He has the
right merely to live on it and to cultivate it. In return he must

84 THE ANDES OF SOUTHERN PERU

work a certain number of days each year on the owner's planta-
tion. In many cases a small money payment is also made to the
planter. The planter prefers labor to money, for hands are
scarce throughout the whole eastern valley region. Xo Indian
need work on the planter's land ^\ithout receiving pay directly
therefor. Each also gets a small Aveekly allotment of aguardiente
while in the planter's employ.

The scene every Saturday night outside the office of the con-
tador (treasurer) of a plantation is a novel one. Several hundred
Indians gather in the dark patio in front of the office. Within
the circle of the feeble candlelight that reaches only the margin
of the crowd one may see a pack of heavy, perspiring faces. Many
are pock-marked from smallpox ; here and there an eye is missing ;
only a few are jovial. A name is shouted through the open door
and an Indian responds. He pulls off his cap and stands stupid
and blinking, while the contador asks :

"Faena" (free)?

''Si, Senor," he answers.

**Un sol" (one "sol" or fifty cents gold). The assistant hands
over the money and the man gives way to the next one on the list.
If he is a laborer in regular and constant employ he receives five
soles (two fifty gold) per week. There are interruptions now and
then. A ragged, half-dninken man has been leaning against the
door post, suspiciously impatient to receive his money. Finally
his name is called.

"Faena?" asks the coiilador.

"No, Senor, cinco (five) soles."

At that the field superintendente glances at liis time card aud
speaks up in protest.

"You were the man that failed lo sliow uj) on l-'i-iday and Sat-
urday. ^ oil wci'c di-iiTik. ^'()ll slioiild receive* nothing."

"Xo, mi pat r('>n,'' llie man contends, "I had to visit a sick
cousin in tlie next \alley. ( »li, lie was very sick, Senor," and he
Cf)ngliH liarsliiy as if lie too were on the verge of prostration. The
sick cousin, a faena Indian, has been at work in another cane field
on the same plantation for two days and now calls out that he is

THE BORDER VALLEYS OF THE EASTERN ANDES 85

present and has never had a sick day in his life. Those outside
laugh uproariously. The contador throws down two soles and
the drunkard is pushed back into the sweating crowd, jostled
right and left, and jeered by all his neighbors as he slinks away
grumbling.

Another Indian seems strangely shy. He scarcely raises his
voice above a whisper. He too is a faena Indian. The contador
finds fault.

''Why didn't you come last month when I sent for youT'

The Indian fumbles his cap, shuffles his feet, and changes his
coca cud from one bulging cheek to the other before he can an-
swer. Then huskily:

''I started, Senor, but my woman overtook me an hour after-
ward and said that one of the ewes had dropped a lamb and
needed care."

' ' But your woman could have tended it ! "

"No, Seiior, she is sick."

"How, then, could she have overtaken you?" he is asked.

' ' She ran only a little way and then shouted to me. ' '

"And what about the rest of the month?" persists the contador.

"The other lambs came, Seiior, and I should have lost them
all if I had left."

The contador seems at the end of his complaint. The Indian
promises to work overtime. His difficulties seem at an end, but
the superintendent looks at his old record.

"He always makes the same excuse. Last year he was three
weeks late."

So the poor shepherd is fined a sol and admonished that his
lands will be given to some one else if he does not respond more
promptly to his patron's call for work. He leaves behind him a
promise and the rank mixed smell of coca and much unwashed
woolen clothing.

It is not alone at the work that they grumble. There is ma-
laria in the lower valleys. Some of them return to their lofty
mountain homes prostrated with the unaccustomed heat and alter-
nately shaking with chills and burning with fever. - Without aid

86 THE ANDES OF SOUTHERN PERU

they may die or become so weakened that tuberculosis carries
them off. Only their rugged strength enables the greater number
to return in good health.

A plantation may be as large as a principality and draw its
laborers from places fifty miles away. Some of the more distant
Indians need not come to work in the canefields. Part of their
flock is taken in place of work. Or they raise horses and mules
and bring in a certain number each year to turn over to the
patron. Hacienda Huadquiiia (Fig. 46) takes in all the land from
the snow-covered summits of the Cordillera Vilcapampa to the
canefields of the Urubamba. Within the broad domain are half
the climates and occupations characteristic of Peru. It is diffi-
cult to see how a thousand Indians can be held to even a mixed
allegiance. ' It seems impossible that word can be got to them.
However the native "telegraph" is even more perfect than that
among the forest Indians. From one to the other runs the news
that they are needed in the canefields. On the trail to and from
a mountain village, in their ramblings from one high pasture to
another, within the dark walls of their stone and mud huts when
they gather for a feast or to exchange drinks of brandy and
chicha — the word is passed that has come up from the valleys.

For e\'ery hundred faena Indians there are five or six regular
laborers on the plantations, so with the short term passed by the
faeiia Indians their number is generally half that of the total
laborers at work at any one time. They live in huts provided for
thoiii l)y llic planter, and in the houses of their friends among the
regular laborers. Here there are almost nightly carousals. The
regular laborer comes from the city or the valley town. The faena
laborer is a small liill farmer or shepherd. They have much to
exchange in llic way oi" clothing, food, and news. I have fre-
(|U«iitly had lla-ir conxcrsal ions interpreted for me. They ask
about, the flocks and tlx- cliildi-cn, who ])assod along the trails, what
accidents befell the jx-ople.

"Last year," droned one to anothei- over their chicha, "last
year we lost three lambs in a hailstorm up in the high fields near
the snow. It was very c<»ld. My foot cracked open and, though

THE BORDER VALLEYS OF THE EASTERN ANDES 87

I have bound it with wet coca leaves every night, it will not cure,"
and he displays his heel, the skin of which is like horn for hard-
ness and covered with a crust of dirt whose layers are a record
of the weather and of the pools he has waded for years.

Their wanderings are the main basis of conversation. They
know the mountains better than the condors do. We hired a small
boy of twelve at Puquiura. He was to build our fires, carry water,
and help drive the mules. He crossed the Cordillera Vilcapampa
on foot with us. He scrambled down into the Apurimac canyon
and up the ten thousand feet of ascent on the other side, twisted
the tails of the mules, and shouted more vigorously then the ar-
rieros. He was engaged to go with us to Pasaje, where his father
would return with him in a month. But he climbed to Huascatay
with us and said he wanted to see Abancay. When an Indian
whom we pressed into service dropped the instruments on the
trail and fled into the brush the boy packed them like a man. The
soldier carried a tripod on his back. The boy, not to be outdone,
insisted on carrying the plane table, and to his delight we called
him a soldier too. He went with us to Huancarama. When I paid
him he smiled at the large silver soles that I put into his hand;
and when I doubled the amount for his willingness to work his joy
was unbounded. Forthwith he set out, this time on muleback, on
the return journey. The last I saw of him he was holding his
precious soles in a handkerchief and kicking his beast with his
bare heels, as light-hearted as a cavalier. Often I find myself won-
dering whether he returned safely with his money. I should very
much like to see him again, for with him I associate cheerfulness
in difficult places and many a pleasant camp-fire.

CHAPTER Vn

THE GEOGRAPHIC BASIS OF REVOLUTIONS AND OF HUMAN
CHARACTER IN THE PERUVIAN ANDES

Human character as a spontaneous development has always
been a great factor in shaping historical events, but it is a strik-
ing fact that in the world of our day its influence is exerted chiefly
in the lowest and highest types of humanity. The savage with
his fetishes, his taboos, and his inherent childlikeness and suspi-
cion needs only whim or a slight religious pretext to change his
conduct. Likewise the really educated and the thoughtful act from
motives often wholly unrelated to economic conditions or results.
But the masses are deeply influenced by whatever affects their
material welfare. A purely idealistic impulse may influence a
people, but in time its effects are ahvays displayed against an eco-
nomic background.

There is a way whereby we may test this theory. In most
places in the world we have history in the making, and through
field studies we can get an intimate view of it. It is peculiarly
the province of geography to study the present distribution
and character of men in relation to their surroundings and
these are the facts of mankind that must forever be the chief
data of economic history. It is not vain repetition to say that this
means, first of all, the study of the character of men in the fullest
sense. Tt means, in the second place, that a large part of the char-
acter must be really understood. Whenever this is done there is
found a geograpliic basis of human character lliat is capable of the
clearest (Icnionslralioii. it is in tiic geographic environment that
the material jn<)li\'('S of Immanity liave struck their deepest roots.

These coiichisions miglit l»e illustrated from a hundred places
in the fiekl of study covered in this l)()()k. Almost every chapter
of Part I contains facts of this charaeter. 1 wish, however, to dis-
ss

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 89

cuss the subject specifically and for that purpose now turn to the
conditions of life in the remoter mountain valleys and to one or
two aspects of the revolutions that occur now and then in Peru.
The last one terminated only a few months before our arrival and
it was a comparatively easy matter to study both causes and
effects.

A caution is necessary however. It is a pity that we use the
term "revolution" to designate these little disturbances. They
affect sometimes a few, again a few hundred men. Rarely do
they involve the whole country. A good many of them are on a
scale much smaller than our big strikes. Most of them involve
a loss of life smaller than that which accompanies a city riot. They
are in a sense strikes against the government, marked by local dis-
orders and a little violence.

Early in 1911 the Prefect of the Department of Abancay had
crowned his long career by suppressing a revolution. He had
been Subprefect at Andahuaylas, and when the rebels got control
of the city of Abancay and destroyed some of the bridges on the
principal trails, he promptly organized a military expedition, con-
structed rafts, floated his small force of men across the streams,
and besieged the city. The rebel force was driven at last to take
shelter in the city jail opposite the Prefectura. There, after the
loss of half their number, they finally surrendered. Seventy-five
of them were sent to the government penitentiary at Arequipa.
Among the killed were sons from nearly half the best families of
Abancay. All of the rebels were young men.

It would be difficult to give an adequate idea of the hatred felt
by the townspeople toward the government. Every precaution
was taken to prevent a renewal of the outbreak. Our coming was
telegraphed ahead by government agents who looked with suspi-
cion upon a party of men, well armed and provisioned, coming up
from the Pasaje crossing of the Apurimac, three days' journey
north. The deep canyon affords shelter not only to game, but also
to fugitives, rebels, and bandits. The government generally
abandons pursuit on the upper edge of the canyon, for only a pro-
longed guerilla warfare could completely subdue an armed force

90 THE ANDES OF SOUTHERN PERU

scattered along its rugged walls and narrow floor. The owner of
the hacienda at Pasaje is required to keep a record of all passen-
gers rafted across the Apurimac, but he explains significantly that
some who pass are too hurried to write their names in his book.
Once he reaches the eastern wall of the canyon a fugitive may
command a view of the entire w^estern wall and note the approach
of pursuers. Thence eastward he has the whole Cordillera Vilca-
pampa in which to hide. Pursuit is out of the question.

AVhen we arrived, the venerable Prefect, a model of old-fash-
ioned courtesy, greeted us with the utmost cordiality. He told us
of our movements since leaving Pasaje, and laughingly explained
that since we had sent him no friendly message and had come
from a rebel retreat, he had taken it for granted that we intended
to storm the town. I assured him that we were ready to join his
troops, if necessary, whereupon, with a delightful frankness, he
explained his method of keeping the situation in hand. Several
troops of cavalry- and two battalions of infantry were quartered
at the government barracks. Every evening the old gentleman,
a Colonel in the Peruvian army, mounted a powerful gray horse
and rode, quite unattended, through the principal streets of the
town. Several times I walked on foot behind him, again I pre-
ceded him, stopping in shops on the way to make trivial purchases,
to find out what the people had to say about him and the govern-
ment as he rode by. One old gentleman interested me particularly,
lie had only the day before called at the Prefectura to pay his
respects. Although his manner was correct there was lacking to
a noticeable degree the profusion of sentiment that is apt to be
exhibited on such an occasion. He now sat on a bench in a shop.
Both his own son and the shopkeeper's son had been slain in the
revolution. It was natural Ihnt they should be bitter. P>ut the
precise nature <•(" ilicir coinpI.-iiTil \v;is wliat interested me most.
One said that lie did not ol^jccj Jo li.-niii^- liis son lose his life for
Ills eouiitry. I'lii 1li;ii liis coiniiry'.s olTicials slionld liiro Indians
to slioot Ilia son seemed to him sheer murder. Later, at Lam-
brama, T talked with a rebel fugitive, and that was also his com-
plaint. The young men drafted into the army are Indians, or

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 91

mixed, never whites. White men, and men with a small amount
of Indian blood, officer the army. When a revolutionary party
organizes it is of course made up wholly of men of white and
mixed blood, never Indians. The Indians have no more grievance
against one white party than another. Both exploit him to the
limit of law and beyond the limit of decency. He fights if he must, /
but never by choice.

Thus Indian troops killed the white rebels of Abancay.

"Tell me, Sefior," said the fugitive, "if you think that just.
Tell me how many Indians you think a white man worth. W^ould
a hundred dead Indians matter! But how replace a white man
where there are so few! The government assassinated my com-
patriots ! "

"But," I replied, "why did you fight the government? All of
you w^re prosperous. Your fathers may have had a grievance
against the government, but of what had you young men to com-
plain?"

His reply was far from convincing. He was at first serious, but
his long abstract statements about taxes and government waste-
fulness trailed off into vagueness, and he ended in a laughing
mood, talking about adventure, the restless spirit of young men,
and the rich booty of confiscated lands and property had the
rebels won. He admitted that it was a reckless game, but when I
called him a mere soldier of fortune he grew serious once more
and reverted to the iniquitous taxation system of Peru. Further
inquiry made it quite clear that the ill-fated revolution of Abancay
.was largely the work of idle young men looking for adventure.
It seemed a pity that their splendid physical energy could not
have been turned into useful channels. The land sorely needs en-
gineers, progressive ranchmen and farmers, upright officials, and
a spirit of respect for law and order. Old men talked of the un-
stable character of the young men of the time, but almost all of
them had themselves been active participants in more than one
revolution of earlier years.

Every night at dinner the Prefect sent off by government tele-
graph a long message to the President of the Republic on the

92 THE ANDES OF SOUTHERN PERU

state of the Department, and received similar messages from the
central government about neighboring departments. These he
read to us, and, curiously enough, to the entire party, made up
of army officers and townsmen. I was surprised to find later that
the company included one government official whose son had been
among the imprisoned rebels at Arequipa. We met the young
man a week later at a mountain village, a day after a general
amnesty had been declared. His escape had been made from the
prison a month before. He forcibly substituted the mess-boy's
clothing for his ow^n, and thus passed out unnoticed. After a few
days ' hiding in the city, he set out alone across the desert of Vitor,
thence across the lofty volcanic country of the Maritime Andes,
through some of the most deserted, inhospitable land in Peru, and
at the end of three weeks had reached Lambrama, near Abancay,
the picture of health !

Later I came to have a better notion of the economic basis of
the revolution, for obviously the planters and the reckless young
men must have had a mutual understanding. Somewhere the
rebels had obtained the sinew^s of war. The planters did not take
an open part in the revolution, but they financed it. When the
rebels were crushed, the planters, at least outwardly, welcomed
the government forces. Inwardly they cursed them for thwart-
ing their scheme. The reasons have an interesting geographic
basis. Abancay is the center of a sugar region. Great irrigated
estates are spread out along the valley floor and the enormous al-
luvial fans built into the main valley at the mouths of the tribu-
tary streams. There is a heavy tax on sugar and on aguardiente
(brandy) manufactured from cane juice. The haccndndos had
dreamed of lighter taxes. The rebels offered the means of secur-
ing relief. But taxes were not the real reason for the unrest, for
many other sugar producers pay the tax without serious com-
pl;iiiit. Ab;iiif'ay is cul off from <lio r(>st of Peru by great moun-
tains. Toward the west, via Antabamba, Cotahuasi, nnd Thuqui-
bamba, two Inmdred milos of frail separate its plantations from
the Pacific. Twelve days' hnrd riding is required to reach Tjimn
over the old colonial trade route. Tt is three days to Cuzco at the

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 93

eud of the three-hundred-mile railway from the port of Mollendo.
The trails to the Atlantic rivers are impossible for trading pur-
poses. Deep sunk in a subtropical valley, the irrigable alluvial
land of Abancay tempts the production of sugar.

But nature offers no easy route out of the valley. For cen-
turies the product has been exported at almost prohibitive cost,
as in the eastern valley of Santa Ana. The coastal valleys
enjoy easy access to the sea. Each has its own port at the
valley mouth, where ocean steamers call for cargo. Many have
short railway lines from port to valley head. The eastern
valleys and Abancay have been clamoring for railways, better
trails, and wagon roads. From the public fund they get what
is left. The realization of their hopes has been delayed too
long. It would be both economic and military strategy to give
them the desired railway. Revolutions in Peru always start
in one of two ways : either by a coup at Lima or an unchecked
uprising in an interior province. Bolivia has shown the way
out of this difficulty. Two of her four large centers — La Paz
and Oruro — are connected by rail, and the line to Cochabamba
lacks only a few kilometres of construction.' To Sucre a line has
been long projected. Formerly a revolution at one of the four
to^^^ls w^as exceedingly difficult to stamp out. Diaz had the same
double motive in encouraging railway building in the remote des-
ert provinces of Northern Mexico, where nine out of ten Mexican
revolutions gather headway. Argentina has enjoyed a high degree
of political unity since her railway system was extended to
Cordoba and Tucuman. The last uprising, that of 1906, took place
on her remotest northeastern frontier.

We had ample opportunity to see the hatred of the rebels. At
nightfall of September 25th w^e rode into the courtyard of Haci-
enda Auquibamba. We had traveled under the worst possible

•According to the latest information (August, 1916) of the Bolivia Rnilway Co..
trains are running from Oruro to Buen Retiro, 35 km. from Cochabamba. Thence
connection with Cochabamba is made by a tram-line operated by the Electric Light and
Power Co. of that city. The Bulletin of the Pan-American Union for July, 1916,
also reports the proposed introduction of an automobile service for conveyance of
freight and passengers.

94: THE ANDES OF SOUTHERN PERU

circumstances. Our mules had been enfeebled by hot valley
work at Santa Ana and the lower Urubamba and the cold moun-
tain climate of the Cordillera Vilcapampa. The climb out of the
Apurimac canyon, even without packs, left them completely ex-
hausted. AVe were obliged to abandon one and actually to pull
another along. It had been a hard day in spite of a prolonged
noon rest. Everywhere our letters of introduction had won
an outpouring of hospitality among a people to whom hospitality
is one of the strongest of the unwritten laws of society. Our sol-
dier escort rode ahead of the pack train.

As the clatter of his mules' hoofs echoed through the dark
buildings the manager rushed out, struck a light and demanded
''Who's there?" To the soldier's cheerful "Buena noche, Senor,"
he sneeringly replied ' ' Halto ! Guardia de la Repiiblica, aqui hay
nada para un soldado del gobierno." Whereupon the soldier
turned back to me and said we should not be able to stop here,
and coming nearer me he whispered "lie is a revolutionary."
I dismounted and approached the haughty manager, who was
in a really terrible mood. Almost before I could begin to
ask him for accommodations he rattled off that there was no
pasture for our beasts, no food for us, and that we had better
go on to the next hacienda. ''Absolutamente nada!" he re-
peated over and over again, and at first I thought him drunk.
Since it was then quite dark, with no moon, but instead heavy
black clouds over the southern half of the sky and a brisk valley
wind threatening rain, I mildly protested that we needed noth-
ing more than shelter. Our food boxes would supply our wants,
aiid oui- mules, even without fodder, could reach Abancay the
next day. SI ill lie stormed at the government and would have
none of us. I reminded him that his fields were filled with
sngMT- cane ;m(l tii;it il \v;is ilie staple forage for beasts during
the part of Iho year when i)as<ure was scarce. The cane was
too valuable, he said. It was impossible to supply us. I was on
llie ]ir)int of j)it('liing camp beside <lie 1i-ail, for it was impossible
to reaeli tlie next hacienda with an exhausted outfit.

Jus< then an older man stopped into the circle of light and ami-

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 95

ably inquired the purpose of our journey. When it was explained,
he turned to the other and said it was unthinkable that men should
be treated so inhospitably in a strange land. Though he himself
was a guest he urged that the host should remember the laws of
hospitality, whereupon the latter at last grudgingly asked us to join
him at his table and to turn our beasts over to his servants. It was
an hour or more before he would exhibit any interest in us. When
he had learned of our object in visiting Abancay he became some-
what more friendly, though his hostility still manifested itself.
Nowhere else in South America have I seen exhibited such boorish
conduct. Nevertheless the next morning I noticed that our mules
had been well fed. He said good-by to us as if he were glad to
be rid of any one in any way connected with the hostile govern-
ment. Likewise the manager at Hacienda Pasaje held out almost
until the last before he would consent to aid us with fresh beasts.
Finally, after a day of courting I gave him a camp chair. He was
so pleased that he not only gave us beasts, but also a letter of
introduction to one of his caretakers on a farm at the top of the
cuesta. Here on a cold, stormy night we found food and fuel and
the shelter of a friendly roof.

A by-product of the revolution, as of all revolutions in thinly
settled frontier regions, was the organization of small bands of
outlaws who infested the lonely trails, stole beasts, and left their
owners robbed and helpless far from settlements. We were cau-
tioned to beware of them, both by Seiior Gonzales, the Prefect at
Abancay, and by the Subprefect of Antabamba. Since some of
the bandits had been jailed, I could not doubt the accuracy of the
reports, but I did doubt stories of murder and of raids by large
companies of mountain bandits. As a matter of fact we were
robbed by the Governor of Antabamba, but in a way that did not
enable us to find redress in either law or lead. The story is worth
telling because it illustrates two important facts: first, the vile
so-called government that exists in some places in the really
remote sections of South America, and second, the character of
the mountain Indians.

The urgent letter from the Prefect of Abancay to the Sub-

96 THE ANDES OF SOUTHERN PERU

prefect of Antabamba quickly brought the latter from liis distant
home. AVhen we arrived we found him drinking with the Gov-
ernor. The Subprefect was most courteous. The Governor w^as
good-natured, but his face exhibited a rare combination of cruelty
and vice. We were offered quarters in the municipal building for
the day or two that we were obliged to stop in the town. The
delay enabled us to study the valley to which particular interest
attaches because of its situation in the mountain zone between
the lofty pastures of the Alpine country and the irrigated fields of
the valley farmers.

Antabamba itself lies on a smooth, high-level shoulder of the
youthful Antabamba Valley. The valley floor is narrow and rocky,
and affords little cultivable land. On the valley sides are steep
descents and narrow benches, chiefly structural in origin, over
which there is scattered a growth of scrub, sufficient to screen the
deer and the bear, and, more rarely, vagrant bands of vicuna that
stray down from their accustomed haunts in the lofty Cordillera.
Three thousand feet above the valley floor a broad shoulder be-
gins (Fig. 60) and slopes gently up to the bases of the true moun-
tains that surmount the broad rolling summit platform. Here are
the great pasture lands of the Andes and their semi-nomadic shep-
herds. The highest habitation in the world is located here at
17,100 feet (5,210 m.), near a secondary pass only a few miles
from the main axis of the western chain, and but 300 feet (91 m.)
below it.

The people of Antabamba are both shepherds and farmers.
The elevation is 12,000 feet (3,658 m.), too high and exposed for
anything more llinii polnhx^s. TIer(» is an Indian i)()j)ulali()ii ])ure-
blooded, and in otlicr respects, too, but litth^ altered fi-om its
original couditioTi. Tlioro is almost no communication with the
outside world. A dccj) canyon fronts the town and a lofty moun-
tain range forms the background.

At nightfall, one ;irt('r nnollicr. Ilic Indi.-nis (';ini(' in fi'om llio
ficlfl nnd do (Ted llicir raps as IIm-v ));isHed our door. 1^'inally came
fhf "Toniente (Jobernador," or Licntcnant Governor. He had
onlv ;i sliirlit strnin of white blood. TTis bonring was that of a

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 97

sneak, and he confirmed this impression by his frank disdain for
his full-blooded townsmen. "How ragged and ugly they are!
You people must find them very stupid," etc. When he found that
we had little interest in his remarks, he asked us if we had ever
seen Lima. We replied that we had, whereupon he said, ' ' Do you
see the gilded cross above the church yonder? I brought that on
muleback all the way from Lima! Think of it! These ignorant
people have never seen Lima!" His whole manner as he drew
himself up and hit his breast was intended to make us think that
he was vastly superior to his neighbors. The sequel shows that
our first estimate of him was correct.

We made our arrangements with the Governor and departed.
To inspire confidence, and at the Governor's urgent request, we
had paid in advance for our four Indians and our fresh beasts —
and at double the usual rates, for it was still winter in the
Cordillera. They were to stay with us until we reached Cota-
huasi, in the next Department beyond the continental divide,
where a fresh outfit could be secured. The Lieutenant Governor
accompanied us to keep the party together. They appeared to
need it. Like our Indian peons at Lambrama the week before,
these had been taken from the village jail and represented the
scum of the town. As usual they behaved well the first day. On the
second night we reached the Alpine country where the vegetation
is very scanty and camped at the only spot that offered fuel and
water. The elevation was 16,000, and here we had the lowest tem-
perature of the whole journey, + 6° F. (—14.4° C). Ice covered
the brook near camp as soon as the sun went down and all night
long the wind blew down from the lofty Cordillera above us, bring-
ing flurries of snow and tormenting our unprotected beasts. It
seemed to me doubtful if our Indians would remain. I discussed
with the other members of the party the desirability of chaining
the peons to the tent pole, but this appeared so extreme a measure
that we abandoned the idea after warning the Teniente that he
must not let them escape.

At daybreak I was alarmed at the unusual stillness about
camp. A glance showed that half our hobbled beasts had

98 THE ANDES OF SOUTHERN PERU

drifted back toward Antabamba and no doubt were now miles
away. The four Indian peons had left also, and their tracks,
half buried by the last snowfall, showed that they had left
hours before and that it was useless to try to overtake them.
Furthermore we were making a topographic map across the
Cordillera, and, in view of the likelihood of snow blockading
the 17,600-foot (5,360 m.) pass which we had to cross, the work
ought not to be delayed. With all these disturbing conditions to
meet, and suffering acutely from mountain sickness, I could
scarcely be expected to deal gently with our official. I drew out
the sleeping Teniente and set him on his feet. To my inquiry
as to the whereabouts of the Indians that he had promised to
guard, he blinlved uncertainly, and after a stupid "Quien sabe?"
peered under the cover of a sheepskin near by as if the peons had
been transformed into insects and had taken refuge under a blade
of grass. I ordered him to get breakfast and after that to take
upon his back the instruments that two men had carried up to
that time, and accompany the topographer. Thus loaded, the
Lieutenant Governor of Antabamba set out on foot a little ahead
of the party. Hendriksen, the topographer, directed him to a
17,000-foot peak near camp, one of the highest stations occupied in
the traverse. When the topographer reached the summit the in-
struments were there but the Teniente had fled. Hendriksen rap-
idly followed the tracks down over the steep snow-covered wall of
a deeply recessed cirque, but after a half-hour's search could not
get sight of tlic niiiauay, whereupon he returned to his station
and took his oljservations, reaching camp in ilie early afternoon.
In the meantime T had intercepted two Indians who had come
from Cotahuasi driving a Ihuna train loaded with corn. They held
a long conversation at the top of the pass above camp and at first
edged suspiciously away. I^ut the rough ground turned them
back into the trail and at last. Ilicy came timidly alon^. Tlioy pre-
tended not 1(> iiiid<'i-sl;iiid Spanish and protested vigorously that
they had to keep on wilji llicir llamas. I thought from the bel-
ligerent attitude of tlie older, which grew rapidly more threaten-
ing as he saw that I was alone, that I was in for trouble, but when

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 99

I drew my revolver he quickly obeyed the order to sit down to
breakfast, which consisted of soup, meat, and army biscuits. I
also gave them coca and cigarettes, the two most desirable gifts
one can make to a plateau Indian, and thereupon I thought I had
gained their friendship, for they at last talked with me in broken
Spanish. The older one now explained that he must at all hazards
reach Matara by nightfall, but he w^ould be glad to leave his son
to help us. I agreed, and he set out forth^vith. The arriero
(muleteer) had now returned with the lost mules and with the as-
sistance of the Indian we soon struck camp and loaded our mules.
I cautioned the arriero to keep close w^atch of the Indian, for at
one time I had caught on his face an expression of hatred more in-
tense than I had ever seen before. The plateau Indian of South
America is usually so stupid and docile that the unexpectedly
venomous look of the man after our friendly conversation and my
good treatment alarmed me. At the last moment, and when our
backs were turned, our Indian, under the screen of the packs,
slipped away from us. The arriero called out to know w^here he
had gone. It took us but a few moments to gain the top of a hill
that commanded the valley. Fully a half-mile away and almost
indistinguishable against the brown of the valley floor was our
late assistant, running like a deer. No mule could follow over that
broken ground at an elevation of 16,000 feet, and so he escaped.

Fortunately that afternoon we passed a half -grown boy riding
back toward Antabamba and he promised to hand the Governor
a note in Spanish, penciled on a leaf of my traverse book. I
dropped all the polite phrases that are usually employed and wrote
as follows :

" Senor Gobernador :

" Your Indians have escaped, likewise the Lieutenant Governor. They have
taken two beasts. In the name of the Prefect of Abancay, I ask you immediately
to brine: a fresh supply of men and animals. We shall encamp near the first pass,
three days west of Antabamba, until you come."

We were now without Indians to carry the instruments, which
had therefore to be strapped to the mules. Without guides we
started westward along the trail. At the next pass the topog-

100 THE ANDES OF SOUTHERN PERU

rapher rode to the summit of d bluff and asked which of the two
trails I intended to follow. Just then a solitary Indian passed
and I shouted back that I would engage the Indian and precede
the party, and he could tell from my course at the fork of the
trail how to direct his map and where to gain camp at nightfall.
But the Indian refused to go with us. All my threatening was
useless and I had to force myself to beat him into submission with
my quirt. Several repetitions on the way, when he stubbornly re-
fused to go further, kept our guide with us until we reached a
camp site. I had offered him a week's pay for two hours' work,
and had put coca and cigarettes into his hands. When these
failed I had to resort to force. Now that he was about to leave I
gave him double the amount I had promised him. He could
scarcely believe his eyes. He rushed up to the side of my mule,
and reaching around my waist embraced me and thanked me
again and again. The plateau Indian is so often waylaid in the
mountains and impressed for service, then turned loose without
pay or actually robbed, that a promise to pay holds no attraction
for him. I liad up to the last moment resembled this class of
white. He was astonished to find that I really meant to pay him
well.

Then he set out upon the return, faithfully delivering my note
to the topographer about the course of the trail and the position
of the camp. He had twelve miles to go to the first mountain hut,
so that he could not have traveled less than that distance to reach
shelter. The next morning a mantle of snow covered everything,
yet when I pushed back the tent flap there stood my scantily clad
Indian of the night before, shivering, with sandaled feet in the
snow, saying that he had come back to work for me !

This camp was number thirteen out of Abancay, and here our
topograpliM- was laid iij) for three days. TTeretoforo the elcxalion
had had no crfcct upon liim, hiil llic excessively lofty stations of
the past few days and I lie liard climbing had finally prostrated
him. We had derided to carry him out by the fourth day if he
felt no better, hut iiappily he recovered sufTiciently to continue the
work. The delay enabled the Governor to overtake us with a fresh

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 101

outfit. On the morniiig of our third day in camp he overtook us
with a small escort of soldiers accompanied by the fugitive
Teniente. He said that he had come to arrest me on the charge of
maltreating an official of Peru. A few packages of cigarettes and
a handful of raisins and biscuits so stirred his gratitude that we
parted the best of friends. Moreover he provided us with four
fresh beasts and four new men, and thus equipped we set out for
a rendezvous about ten miles away. But the faithless Governor
turned off the trail and sought shelter at the huts of a company
of mountain shepherds. That night his men slept on the ground
in a bitter wind just outside our camp at 17,200 feet. They com-
plained that they had no food. The Governor had promised to
join us with llama meat for the peons. We fed them that night
and also the next day. But we had by that time passed the crest
of the western Cordillera and were outside the province of Anta-
bamba. The next morning not only our four men but also our
four beasts were missing. We were stranded and sick just under
the pass. To add to our distress the surgeon, Dr. Erving, was
obliged to leave us for the return home, taking the best saddle
animal and the strongest pack mule. It was impossible to go on
with the map. That morning I rode alone up a side valley until
I reached a shepherd 's hut, where I could find only a broken-down,
shuffling old mule, perfectly useless for our hard work.

Then there happened a piece of good luck that seems almost
providential. A young man came down the trail with three pack
mules loaded with llama meat. He had come from the Cotahuasi
Valley the week before and knew the trail. I persuaded him to
let us hire one of his mules. In this way and by leaving the in-
struments and part of our gear in the care of two Indian youths
we managed to get to Cotahuasi for rest and a new outfit.

The young men who took charge of part of our outfit interested
me very greatly. I had never seen elsewhere so independent and
clear-eyed a pair of mountain Indians. At first they would have
nothing to do with us. They refused us permission to store our
goods in their hut. To them we were railroad engineers. They
said that the railway might come and when it did it would depopu-

102 THE ANDES OF SOUTHERN PERU

late the country. The railway was a curse. Natives were obliged
to work for the company without pay. Their uncle had told them
of frightful abuses over at Cuzco and had warned them not to
help the railway people in any way. They had moved out here
in a remote part of the mountains so that white men could not
exploit them.

In the end, however, we got them to understand the nature of
our work. Gifts of various sorts won their friendship, and they
consented to guard the boxes we had to leave behind. Two weeks
later, on his return, the topographer found everything unmolested.

I could not but feel that the spirit of those strong and inde-
pendent young men was much better for Peru than the cringing,
subservient spirit of most of the Indians that are serfs of the
whites. The policy of the whites has been to suppress and ex-
ploit the natives, to abuse them, and to break their spirit. They
say that it keeps down revolution; it keeps the Indian in his place.
But certainly in other respects it is bad for the Indian and it is
worse for the whites. Their brutality toward the natives is in-
credible. It is not so much the white himself as the vicious half-
breed who is often allied with him as his agent.

I shall never forget the terror of two young girls driving a don-
key before them when they came suddenly face to face with our
party, and we at the same time hastily scrambled off our beasts
to got a photograph of a magnificent view disclosed at the bend
of the steep trail. They thought we had dismounted to attack
them, iiu(] fled screaming in abject fear up the mountain side,
abandoning 1lif donkey and the pack of potatoes which must have
represented a large part of the season's product. It is a kind of
highway roy)bery condoned because it is only robbing an Indian.
Tic is considered to he lawful prey. His complaint goes unnoticed.
In tlio past a rovolntion lias offered him sporadic chances to wreak
vcni^caiK'f. More oflcn it, adds to liis troubles by scattering
through the mountain xallcys tin* desperate refugees or lawless
bands of niarandcrs wlio kill tlic floeks of tho nionntain shepherds
and despoil their women.

There are still considerable numbers of Indians wlio shun the

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 103

white man and live in the most remote corners of the mountains.
I have now and again come upon the most isolated huts, invisible
from the valley trails. They were thatched with grass ; the walls
were of stone; the rafters though light must have required pro-
digious toil, for all timber stops at 12,000 feet on the mountain
borders. The shy fugitive who perches his hut near the lip of a
hanging valley far above the trail may look down himself unseen
as an eagle from its nest. When the owner leaves on a journey,
or to take his flock to new pastures, he buries his pottery or hides
it in almost inaccessible caves. He locks the door or bars it, thank-
ful if the spoiler spares rafters and thatch.

At length we reached Cotahuasi, a town sprawled out on a ter-
race just above the floor of a deep canyon (Fig. 29) . Its flower gar-
dens and pastures are watered by a multitude of branching canals
lined with low willows. Its bright fields stretch up the lower
slopes and alluvial fans of the canyon to the limits of irrigation
where the desert begins. The fame of this charming oasis is wide-
spread. The people of Antabamba and Lambrama and even the
officials of Abancay spoke of Cotahuasi as practically the end of
our journey. Fruits ripen and flowers blossom every month
of the year. Where we first reached the canyon floor near
Huaynacotas, elevation 11,500 feet (3,500 m.), there seemed to be
acres of rose bushes. Only the day before at an elevation of
16,800 feet (5,120 m.) we had broken thick ice out of a mountain
spring in order to get water ; now we were wading a shallow river,
and grateful for the shade along its banks. Thus we came to the
town prepared to find the people far above their plateau neigh-
bors in character. Yet, in spite of friendly priests and officials
and courteous shopkeepers, there was a spirit strangely out of
harmony with the pleasant landscape.

Inquiries showed that even here, where it seemed that only
sylvan peace should reign, there had recently been let loose the
spirit of barbarism. We shall turn to some of its manifestations
and look at the reasons therefor.

In the revolution of 1911 a mob of drunken, riotous citizens
gathered to storm the Cotahuasi barracks and the jail. A full-

104 THE ANDES OF SOUTHERN PERU

blooded Indian soldier, on duty at the entrance, ordered the rioters
to stop and when they paid no heed he shot the leader and scat-
tered the crowd. The captain thereupon ordered the soldier to
Arequipa because his life was no longer safe outside the barracks.
A few months later he was assigned to Professor Bingham's
Coropuna expedition. Professor Bingham reached the Cotahuasi
Valley as I was about to leave it for the coast, and the soldier was
turned over to me so that he might leave Cotahuasi at the earliest
possible moment, for his enemies were plotting to kill 'him.

He did not sleep at all the last night of his stay and had us
called at three in the morning. He told his friends that he was
going to leave with us, but that they were to announce his leav-
ing a day later. In addition, the Subprefect was to accompany
us until daybreak so that no harm might befall me while under
the protection of a soldier who expected to be shot from ambush.

At four o'clock our whispered arrangements were made, we
opened the gates noiselessly, and our small cavalcade hurried
through the pitch-black streets of the town. The soldier rode
ahead, his rifle across his saddle, and directly behind him rode
the Subprefect and myself. The pack mules were in the rear. We
had almost reached the end of the street when a door opened sud-
denly and a shower of sparks flew out ahead of us. Instantly the
soldier struck spurs into his mule and turned into a side street.
The Subprefect drew his horse back savagely and when the next
shower of sparks flew out pushed me against the wall and
whispered: "i'oi- Dios, quien es?" Then suddenly lie shouted:
*'S<>i)la no mas, sojjhi no mas" (stop blowing).

'I'licrfiipon a shabl)y penitent man came to the door holding in
his li.iiid a largo tailor's flatiron. The base of it was filled with
glnuiiiL'- cli.'irco;!! iiikI he was a])()ut to stai't his day's work. The
sparks were mndc in llic i)rocess (d" blowing lliroiigli llic ii'on to
start tlie smoldering coals. We greeted liini willi moi-c tlian
ordiii.'iry friendliness and passed on.

At daybreak we li;id reached tlu; steej) western wall of the
canyon where the re;d ascent begins, and here the Subprefect
tuiiied h.'ick with many felicidades for the journey and threats

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 105

for the soldier if he did not look carefully after the pack train.
From every angle of the zigzag trail that climbs the "cuesta" the
soldier scanned the valley road and the trail below him. He was
anxious lest news of his escape reach his enemies who had vowed
to take his life. Half the day he rode turned in his saddle so as
to see every traveler long before he was within harm's reach. By
nightfall we safely reached Salamanca, fifty miles away (Fig. 62).

The alertness of the soldier was unusual and I quite enjoyed
his close attention to the beasts and his total abstinence, for an
alert and sober soldier on detail is a rare phenomenon in the in-
terior of Peru. But all Salamanca was drunk when we arx iyed
— Governor, alcaldes, citizens^ Even the peons drank up in brandy
the money that we gave them for forage and let the beasts starve.
The only sober person I saw was the white telegraph operator
from Lima. He said that he had to stay sober, for the telegraph
office — the outward sign of government — was the special object
of attack of every drink-crazed gang of rioters. They had tried
to break in a few nights before and he had fired his revolver point-
blank through the door. The town offered no shelter but the dark
filthy hut of the Gobernador and the tiny telegraph office. So I
made up my bed beside that of the operator. We shared our meals
and chatted until a late hour, he recounting the glories of Lima,
to which he hoped to return at the earliest possible moment, and
cursing the squalid town of Salamanca. His operator's keys were
old, the batteries feeble, and he was in continual anxiety lest a
message could not be received. In the night he sprang out of bed
shouting frantically :

"Estan llamando" (they are calling), only to stumble over my
bed and awaken himself and offer apologies for walking in his
sleep.

Meanwhile my soldier, having regained his courage, began
drinking. It was with great difficulty that I got started, after a
day's delay, on the trail to Chuquibamba. There his thirst quite
overcame him. To separate him from temptation it became nec-
essary to lock him up in the village jail. This I did repeatedly on
the way to Mollendo, except beyond Quilca, where we slept in the

106 THE ANDES OF SOUTHERN PERU

hot marshy valley out of reach of drink, and where the mosquitoes
kept us so busy that either eating or drinking was almost out of
the question.

The drunken rioters of Cotahuasi and their debauched brothers
at Salamanca are chietiy natives of pure or nearly pure Indian
blood. They are a part of the great plateau population of the
Peruvian Andes. Have they degenerated to their present low
state, or do they display merely the normal condition of the
plateau people? Why are they so troublesome an element? To
this as to so many questions that arise concerning the highland
population we find our answ^er not chiefly in government, or re-
ligion, or inherited character, but in geography. I doubt very
much if a greater relative difference would be seen if two groups
of whites were set do^\^l, the one in the cold terrace lands of
Salamanca, the other in the warm vineyards of Aplao, in the Majes
\'alley. The common people of these two towns were originally
of the same race, but the lower valley now has a white element
including even most of those having the rank of peons. Greater
differences in character could scarcely be found between the Aztecs
and the Iroquois. In the warm valley there is of coarse drunken-
ness, but it is far from general ; there is stupidity, but the people
are as a whole alert; and finally, the climate and soil produce
grapes from which famous \vines are made, they produce sugar
cane, cotton, and alfalfa, so that the whites have come in, diluted
the Indian blood, and raised the standard of life and behavior.
Undouljtodly their influence would tend to have the same general
effect if they mixed in equal numbers with the plateau groups.
Tliorc is, however, a good reason for their not doing so.

The lofty towns of the plateau have a really wretched climate.
\\ liitf men cannot live comfortably at Antabamba and Salamanca.
i''inlli<r. tlioy arc so isolated that the modest comforts and the
smallesl luxuries of civilization are very expensive. To ])ay for
them requires a profitable industry managed on a large scale and
tlicre is iio such industry in the higher valleys. The white who
goes there must he s/itisfied to live like an Indian. The result is
easy to forecast Hnlside of government officers, only the disso-

Fig. G1.

Fig. 60 — View across the Aiitabaniba canyon just above Huadquirca.
Fig. 61 — Huancarama, west of Abancay, on the famous Lima to Bueno;
road. Note the smooth slopes in the fore<j;round. See Chapter XI.

Aires

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 107

lute or unsuccessful whites live in the worst towns, like Salamanca
and Antabamba. A larger valley with a slightly milder climate
and more accessible situation, like Chuquibamba, will draw a still
better grade of white citizen and in the largest of all — Cuzco and
the Titicaca basin — we find normal whites in larger numbers,
though they nowhere live in such high ratios to the Indian as on
the coast and in the lower valleys near the coast. With few ex-
ceptions the white population of Peru is distributed in response
to favorable combinations of climate, soil, accessibility, and gen-
eral opportunities to secure a living without extreme sacrifice.'" -..

These facts are stated in a simple way, for I wish to emphasize
the statement that the Indian population responds to quite other
stimuli. Most of the luxuries and comforts of the whites mean
nothing to the Indian. The machine-made woolens of the im-
porters will probably never displace his homespun llama-wool ^
clothing. His implements are few in number and simple in form.
His tastes in food are satisfied by the few products of his fields '
and his mountain flocks. Thus he has lived for centuries and is
quite content to live today. Only coca and brandy tempt him to
engage in commerce, to toil now and then in the hot valleys, and
to strive for more than the bare necessities of life. Therefore
it matters very little to him if his home town is isolated, or the
resources support but a small group of people. He is so ac-
customed to a solitary existence in his ramblings with his flocks
that a village of fifty houses offers social enjoyments of a high
order. Where a white perishes for lack of society the Indian finds
himself contented. Finally, he is not subject to the white man's
exploitation when he lives in remote places. The pastures are ex-
tensive and free. The high valley lands are apportioned by the
alcalde according to ancient custom. His life is unrestricted by
anything but the common law and he need have no care for the
morrow, for the seasons here are almost as fixed as the stars. /

Thus we have a sort of segregation of whites in the lower
places where a modern type of life is maintained and of Indians
in the higher places where they enjoy advantages that do not ap-
peal to the whites. Above 8,000 feet the density of the white popu-

108 THE ANDES OF SOUTHERN PERU

latiou bears a close inverse proportion to the altitude, excepting
in the case of the largest valleys whose size brings together such
numbers as to tempt the commercial and exploiting whites to live
in them. Furthermore, we should find that high altitude, limited
size, and greater isolation are everywhere closely related to in-
creasing immorality or decreasing character among the whites. So
to the low Indian population there is thus added the lowest of the
white population. Moreover, because it yields the largest returns,
the chief business of these whites is the sale of coca and brandy
and the downright active debauchery of the Indian. This is all
the easier for them because the isolated Indian, like the average
isolated white, has only a low and provincial standard of morality
and gets no help from such stimulation as numbers usually excite.

For example, the Anta basin at harvest time is one of the fair-
est sights in Peru. Sturdy laborers are working diligently. Their
faces are bright and happy, their skin clear, their manner eager
and animated. They sing at their work or gather about their mild
chicha and drink to the patron saints of the harvest. The huts are
filled with robust children ; all the yards are turned into threshing
floors; and from the stubbly hillslopes the shepherd blows shrill
notes upon his barley reeds and bamboo flute. There is drinking
but there is little disorder and there is always a sober remnant
that exercises a restraining influence upon the group.

In the most remote places of all one may find mountain groups
of a high order of morality unaffected by the white man or actu-
ally shunning him. Clear-eyed, thick-limbed, independent, a fine,
sturdy type of man this highland shepherd may be. But in the
town ho succumbs to the temptation of drink. Some writers have
tried to mak(.' him out a superior to the plains and low valley type.
Ho is not lliat. Tho well-regulated groups of the lower elevations
arc I'-AV superior intellectually and morally in spite of the fact that
tlio [)oor]y regulated groups may fall below tho highland dweller
in ni«tr;ility. Tlie coca-chowing highlandcr is a clod. Surely, as
a whole, the mixed Ijrood of the coastal valleys is a far worthier
type, save in a few cases whore; a ('iiincse or negroid element or
both have led to local inferiority. And surely, also, that is the

THE GEOGRAPHIC BASIS OF HUMAN CHARACTER 109

worst combination which results in adding the viciousness of the
inferior or debased white to the stupidity of the highland Indian.
It is here that the effects of geography are most apparent. If the
white is tempted in large numbers because of exceptional position
or resources, as at La Paz, the rule of altitude may have an excep-
tion. And other exceptions there are not due to physical causes,
for character is practically never a question of geography alone.
There is the spiritual factor that may illumine a strong character
and through his agency turn a weak community into a powerful
one, or hold a weakened group steadfast against the forces of dis-
integration. Exceptions arise from this and other causes and yet
mth them all in mind the geographic factor seems predominant in
the types illustrated heremth.^

^ During his travels Raimondi collected many instances of the isolation and con-
servatism of the plateau Indian: thus there is the village of Pampacolca near Coro-
puna, whose inhabitants until recently carried their idols of clay to the slopes of the
great white moimtain and worshiped them there with the ritual of Inca days (El Peru,
Lima, 1874, Vol. 1).

CHAPTER VIII
THE COASTAL DESERT

To the wayfarer from the bleak mountains the warm green val-
leys of the coastal desert of Peru seem like the climax of scenic
beauty. The streams are intrenched from 2,000 to 4,000 feet, and
the valley walls in some places drop 500 feet by sheer descents
from one level to another. The cultivated fields on the valley
floors look like sunken gardens and now and then one may catch
the distant glint of sunlight on water. The broad white path that
winds through vineyards and cotton-fields, follows the foot of a
cliff, or fills the whole breadth of a gorge is the waste-stre^vn,
half-dr>' channel of the river. In some places almost the whole floor
is cultivated from one valley wall to the other. In other places
the fields are restricted to narrow bands between the river and the
impending cliffs of a narrow canyon. Where tributaries enter
from the desert there may be huge banks of mud or broad triangu-
lar fans covered with raw, infertile earth. The picture is gener-
ally touched with color — a yellow, haze-covered horizon on the bare
desert above, brown lava flows suspended on the brink of the val-
ley, gray-brown cliffs, and greens ranging from the dull shade of
algarrobo, olive and fig trees, to the bright shade of freshly irri-
gated alfalfa pastures.

After several months' work on the cold highlands, where we
rode almost daily into hailstorms or wearisome gales, Ave came at
length to the border of the valley country. It will always seem to
me that the weather and llie sky conspired that afternoon to re-
ward us for llie months of toil that lay behind. And certainly
there could be no happier place to receive the reward than on the
brink of the lava plateau above Chuquibamba. There was prom-
ise of an extraordiunry view in the growing beauty of the sky,
and we hurried our tired beasts forward so that the valley below

Fig. 63.

Fig. 04.

Fig. 63— The deep fertile Majes Valley below Cantas. Compare with Fig. 6 show-
ing the Chili Valley at Arequipa.

Fig. 64— The Majes Valley, desert coast, western Peru. The lighter patches on the
valley floor are the gravel beds of the river at high water. :Much of the alluvial land
is still uncleared.

THE COASTAL DESERT 111

miglit also be included in the picture. The head of the Majes Val-
ley is a vast hollow bordered by cliffs hundreds of feet high, and
we reached the rim of it only a few minutes before sunset.

I remember that we halted beside a great wooden cross and
that our guide, dismounting, walked up to the foot of it and kissed
and embraced it after the custom of the mountain folk when they
reach the head of a steep '^cuesta." Also that the trail seemed
to drop off like a stairway, which indeed it was.^ Everything else
about me was completely overshadowed by sno^vy mountains, col-
ored sky, and golden-yellow desert. One could almost forget the
dark clouds that gather around the great mass of Coropuna and
the bitter winds that creep down from its glaciers at night — it
seemed so friendly and noble. Behind it lay bulky masses of rose-
tinted clouds. We had admired their gay colors only a few min-
utes, when the sun dropped behind the crest of the Coast Range
and the last of the sunlight played upon the sky. It fell with such
marvelously swift changes of color upon the outermost zone of
clouds as these were shifted with the wind that the eye had
scarcely time to comprehend a tint before it was gone and one
more beautiful still had taken its place. The reflected sunlight
lay warm and soft upon the white peaks of Coropuna, and a little
later the Alpine glow came out delicately clear.

When we turned from this brilliant scene to the deep valley,
we found that it had already become so dark that its greens had
turned to black, and the valley walls, now in deep shadow, had lost
half their splendor. The color had not left the sky before the
lights of Chuquibamba began to show, and candles twinkled from
the doors of a group of huts close under the cliff. We were not
long in starting the descent. Here at last were friendly habita-
tions and happy people. I had worked for six weeks between
12,000 and 17,000 feet, constantly ill from mountain sickness, and
it was with no regret that I at last left the plateau and got down

' Raimondi (op. cit., p. 109) has a characteristic description of the " Camino del
Penon " in the department of La-Libertad: "... the ground seems to disappear from
one's feet; one is standing on an elevated balcony looking down more than 6,000 feet
to the valley . . . the road which descends the steep scarp is a masterpiece."

112

THE ANDES OF SOUTHERN PERU

to comfortable altitudes. It seemed good news when the guide
told me that there were mosquitoes in the marshes of Camana.
Any low, hot land would have seemed like a health resort. I had
been in the high country so long that, like the Bolivian mining
engineer, I wanted to get down not only to sea level, but below it !
If the reader will examine Figs. 65 and 66, and the photographs
that accompany them, ho may gain an idea of the more important

Fig. 65 — Ili-gional diagram to show the physical relations in the coastal desert
of Peru. For location, see Fig. 20.

features of the coastal region. We have already described, in
Chapters \' ;iii(l V'll, the character of the plateau region and its
people. Therefore, we need say little in this place of the part
of the Maritime Cordillera that is included in the figure. Its
unjjopulated rim (see p. 54), the semi-nomadic ftlerdsmen and slicp-
herds from (,Tiu(iuibamba that scour its pastures in the moist
vales about Coropuna, and the gnarled an^ stunted trees at 13,000
feet (3,900 m.) wltidi partly supply Chuquibamba with firewood,
are its most impoj-ianl features. A few gr()ui)s of hiiis just under
the snowliiK- nrc iiili;il)i1c(| Ww only a ])art of the year. The de-
lightful vjillcvH .-ire loo near aud tempting. Even a plateau
Indian responds to liic call of a dry valley, however he may shun
the moist, warm valleys on the eastern border of the Cordillera.

THE COASTAL DESERT

113

Fig. 66 — Irrigated and irrigable land of the coastal belt of Peru. The map ex-
hibits in a striking manner how small a part of the whole Pacific slope is available for
cultivation. Pasture grows over all but the steepest and th6 highest portions of the
Cordillera to the right of (above) the dotted line.' Another belt of pasture too nar-
row to show on the map, grows in the fog belt on the seaward slopes of the Coast
Range. Scale, 170 miles to the inch.

114 THE ANDES OF SOUTHERN PERU

The greater part of the coastal region is occupied by the des-
ert. Its outer border is the low, dry, gentle, eastward-facing slope
of the Coast Eange. Its inner border is the foot of the steep
descent that marks the edge of the lava plateau. This descent is
a fairly well-marked line, here and there broken by a venturesome
lava flow that extends far out from the main plateau. Within
these definite borders the desert extends continuously northwest-
ward for hundreds of miles along the coast of Peru from far be-
yond the Chilean frontier almost to the border of Ecuador. It is
broken up by deep tranverse valleys and canyons into sorcalled
** pampas," each of which has a separate name; thus west of
Arequipa between the Vitor and Majes valleys are the "Pampa
de Vitor" and the ''Pampa de Sihuas," and south of the Vitor
is the "Pampa de Islay."

The pampa surfaces are inclined in general toward the sea.
They were built up to their present level chiefly by mountain
streams before the present deep valleys were cut, that is to say,
when the land was more than a half-mile lower. Some of their
material is wind-blown and on the walls of the valleys are alter-
nating belts of wind-blown and water-laid strata from one hun-
dred to four hundred feet thick as if in past ages long dry and
long wet periods had succeeded each other. The wind has blown
sand and dust from the desert down into the valleys, but its chief
work has been to drive the lighter desert waste up partly into the
mountains and aloiii;- llicir margins, partly so high as to carry it*
into tlic roalni of tiio lofty terrestrial winds, whence it falls upon
surfaces far distant from the fields of origin. Tliero are left
behind the ln-avicr sand which the wind rolls along on the sur-
faces and builds into crescentic dunes called medanos, and the peb-
blos that it can sandpaper but cannot remove bodily. Thus there
i\»' belts of dunes, belts of irregular sand drifts, and bells of true
d^'Rert "pavement" (a residual mantle of faceted pebbles and
irrerriilar .stones).

Vet anollier feature of the desert pampa are the "dry" val-
leys that Join the through-flowing streams at irregular intervals,
as shown in the accompanying regional diagram. If one follow

16" 2i

^EDIT,
IRE CI

ZVfl.

CAiSASX OnADRAirtS^

TJn-TiF:

I' A (• I /•• / (■

(> c /■: A .\

THE COASTAL DESERT 115

a dry valley to its head lie will find there a set of broad and shal-
low tributaries. Sand drifts may clog them and appear to indi-
cate that water no longer flows through them. They are often re-
ferred to by unscientific travelers as evidences of a recent change
of climate. I had once the unusual opportunity (in the mountains
of Chile) of seeing freshly fallen snow melted rapidly and thus |
turned suddenly into the streams. In 1911 this happened also at
San Pedro de Atacama, northern Chile, right in the desert at ',
8,000 feet (2,440 m.) elevation, and in both places the dry, sand- ^^
choked valleys were cleaned out and definite channels reestab-
lished. From a large number of facts like these we know that the
dry valleys represent the work of the infrequent rains. No desert
is absolutely rainless, although until recently it was the fashion
to say so. Naturally the wind, which works incessantly, partly
offsets the work of the water. Yet the wind can make but little
impression upon the general outlines of the dry valleys. They re-
main under the dominance of the irregular rains. These come
sometimes at intervals of three or four years, again at intervals
of ten to fifteen years, and some parts of the desert have probably
been rainless for a hundred years. Some specific cases are dis-
cussed in the chapter on Climate. v

The large valleys of the desert zone have been cut by snow-
fed streams and then partly filled again so that deep waste lies on
their floors and abuts with remarkable sharpness against the bor-
dering cliffs (Fig, 155). Extensive flats are thus available for
easy cultivation, and the through-flowing streams furnish abundant
water to the irrigatin;<r canals. The alluvial floor begins almost
at the foot of the stjep w^estern slope of the lava plateau, but it is
there stony and ;joarse — honce Chuquibamba, or plain of stones
(chuqui=stone ; bamba=plain) . Farther down and about half-w^ay
between Chuquibamba and Aplao (Camana Quadrangle) it is partly
covered with fresh mud and sand flows from the bordering valley
walls and the stream is intrenched two hundred feet. A few miles
above Aplao the stream emerges from its narrow gorge and thence-
forth flows on the surface of the alluvium right to the sea. Nar-
row places occur between Cantas and Aplao, where there is a pro-

116 THE ANDES OF SOUTHERN PERU

jection of old and hard quartzitic rock, and again above Camana,
where the stream cuts straight across the granite axis of the Coast
Range. Elsewhere the rock is either a softer sandstone or still
unindurated sands and gravels, as at the top of the desert series
of strata that are exposed on the valley wall. The changing width
of the valley is thus a reflection of the changing hardness of the
rock.

There is a wide range of products between Chuquibamba at
10,000 feet (3,050 m.) at the head of the valley and Camana near
the valley mouth. At the higher levels fruit will not grow — only
alfalfa, potatoes, and barley. A thousand feet below Chuqui-
bamba fruit trees appear. Then follows a barren stretch where
there are mud flows and where the river is intrenched. Below
this there is a wonderful change in climate and products. The
elevation falls off 4,000 feet and the first cultivated patches
below the middle unfavorable section are covered with grape
vines. Here at 3,000 feet (900 m.) elevation above the sea begin
the famous vineyards of the Majes Valley, which support a wine
industry that dates back to the sixteenth century. Some of the
huge buried earthenware jars for curing the wine at Hacienda
Cantas were made in the reign of Philip II.

The people of Aplao and Camana are among the most hospita-
ble and energetic in Peru, as if those qualities were but the re-
flection of the bounty of nature. Nowhere could I see evidences
of crowding or of the degeneracy or poverty that is so often as-
sociated willi desert people. Water is always plentiful; some-
times indeed too plentiful, for floods and changes in the bed of
the ri\-('i- arc rcsponsil^lc for the loss of a good deal of land.
This aijuiidance of water moans that both the small and the large
landowners receive enough. There are none of the troublesome
ofTicial regulations, as in the poorer valleys willi llieir inevitable
faxoritisiii or downi-iulil urnri. Vet even here Uio valley is not
fully occupied; at many places more land could be put under
cultivation. Tlio Px-hmnde brothers at Cantas have illustrated
this in their new cotton plantation, where clearings and new canals
have turned into cultivated fields tracts long covered with brush.

THE COASTAL DESERT 117

The Majes Valley sorely lacks an adequate port. Its cotton, '
sugar, and wine must now be shipped to Camana and thence to
Mollendo, either by a small bi-weekly boat, or by pack-train over
the coast trail to Quilca, where ocean steamers call. This is so
roundabout a way that the planters of the mid-valley section and
the farmers of the valley head now export their products over the
desert trail from Cantas to Vitor on the Mollendo-Arequipa rail-
road, whence they can be sent either to the cotton mills or the
stores of Arequipa, the chief distributing market of southern
Peru, or to the ocean port.

The foreshore at Camana is low and marshy where the salt
water covers the outer edge of the delta. In the hollow between
two headlands a broad alluvial plain has been formed, through
which the shallow river now discharges. Hence the natural inden- \
tation has been filled up and the river shoaled. To these disad- /
vantages must be added a third, the shoaling of the sea bottom, I
which compels ships to anchor far off shore. Such shoals are so '
rare on this dry and almost riverless coast as to be a menace to
navigation. The steamer Tucapelle, like all west-coast boats, was
sailing close to the unlighted shore on a very dark night in
April, 1911, when the usual fog came on. She struck the reef just
off Camana. Half of her passengers perished in trying to get
through the tremendous surf that broke over the bar. The most
practicable scheme for the development of the port would seem to
be a floating dock and tower anchored out of reach of the surf,
and connected by cable with a railway on shore. Harbor works
would be extraordinarily expensive. The valley can support only
a modest project.

The relations of Fig. 65, representing the Camana-Vitor re-
gion, are typical of southern Peru, with one exception. In a few
valleys the streams are so small that but little water is ever found
beyond the foot of the mountains, as at Moquegua. In the Chili
Valley is Arequipa (8,000 feet), right at the foot of the big cones
of the Maritime Cordillera (see Fig. 6). The green valley floor
narrows rapidly and cultivation disappears but a few miles below
the town. Outside the big valleys cultivation is limited to the best

118

THE ANDES OF SOUTHERN PERU

spots along the foot of the Coast Range, where tiny streams or
small springs derive water from the zone of clouds and fogs on the
seaward slopes of the Coast Range. Here and there are olive
groves, a vegetable garden, or a narrow alfalfa meadow, watered

_ ... . _,„., .

^IJHITS OF mR10*BLf LAND y*^ ,

\~ )/' -M

'^^~~%A/y^^ "/yy^ 1

SCALE

5 lOkms

^••v COORDINATES Of ICA
,-■' lONC 7S"30' WorC
^1 ur. !♦• S

I KyCK.

\
/

, *Iq \^

LIMITS Of

lltRKABLe LAND

[>;>^^ IRRIGATED LAND

Flu. (i7 — Irrigati'il and irrigable land Fig, GS — The projected canal to con-

in the lea Valley of the coastal desert of vey water from the Atlantic slope to the
Peru. Pacific slope of the ^laritinie Cordillera.*

by uncertain springs that issue below tlie hollows of tlie bordering
mountains.

In central and iioitlicrn I'eru the coastal region has as])octs
quite differcTif I'l-oni those about Camana. At some places, for
examine iiorfli of" (Nmto A/ul, the main s])ni"s of llic Cordillera
extend down 1o llic sliocc. HMid'c is iicillicr n low (*oast Range
nor a lii'ond di'sci-l |);iin|ia. In sncli places (lal land is found only
on tlu' alluvial fans and deltas. Ijima and ('nllao are typical.
P^ig. on, c()mj)iled from Adams's reports on tlie water resources of

•FigH. 07 and R« are from T^ol. do Minns dr] Pern, 1000, No. .17. pp. R2 and 84
resppctively.

'^\

THE COASTAL DESERT

119

the coastal region of Peru, shows this distinctive feature of the
central region. Beyond Salaverry extends the northern region,
where nearly all the irrigated land is found some distance back
from the shore. The farther north we go the more marked is this

3M
2M

JAN

FEB

MARCH

APRIL

MAY

JUNE

JULY

AUG

SEPT

OCT.

NOV 1 DEC

i
1

Fig. 69 — A stream of the intermittent type in the coastal desert of Peru. Depth
of water in the Puira River at Puira, 1905. (Bol. de Minas del Peru, 1906, No. 45, p. 2.)

feature, because the coastal belt widens. Catacaos is several miles
from the sea, and Piura is an interior place. At the extreme north,
where the rains begin, as at Tumbez, the cultivated land once more
extends to the coast.

These three regions contain all the fertile coastal valleys of
Peru. The larger ones are impressive — with cities, railways,

JAN. FEB MARCH APRIL MAY JUNE JULY AUG. SEPT. OCT

Fig. 70 — A stream of the perennial type in the coastal desert of Peru. Depth of
water in the Chira River at Sullana, 1905. Data from May to September are ap-
proximate. (Bol. de Minas del Peru, 1906, Xo. 45, p. 2.)

ports, and land in a high state of cultivation. But they are after-^
all only a few hundred square miles in extent. They contain less !
than a quarter of the people. The whole Pacific slope from the
crest of the Cordillera has about 15,000 square miles (38,850 sq.
km.), and of this only three per cent is irrigated valley land, as
shown in Fig. 66. Moreover, only a small additional amount may
be irrigated, perhaps one half of one per cent. Even this amount

120 THE ANDES OF SOUTHERN PERU

may be added not only by a better use of the water but also by the
diversion of streams and lakes from the Atlantic to the Pacific.
Figs. 67 and 6S represent such a project, in which it is proposed to
carry the water of Lake Choclococha through a canal and tunnel
under the continental divide and so to the head of the lea Valley.
A little irrigation can be and is carried on by the use of well water,
but this will never be an important source because of the great
depth to the ground water, and the fact that it, too, depends ulti-
mately upon the limited rains.

The inequality of opportunity in the various valleys of the
coastal region depends in large part also upon inequality of
river discharge. This is dependent chiefly upon the sources of the
streams, whether in sno^vy peaks of the main Cordillera with
fairly constant run-off, or in the w^estern spurs where summer
rains bring periodic high water. A third type has high water dur-
ing the time of greatest snow melting, combined with summer
rains, and to this class belongs the Majes Valley with its sources
in the snow-cap of Coropuna. The other two types are illustrated
by the accompanying diagrams for Puira and Chira, the former
intermittent in flow, the latter fairly constant."

• The BoleWn de IMinas del PerG, No. 34, 1905. contains a graphic representation
of the regime of the Rio Chili at Arequipa for the years 1901-1905.

0? 1911

-.Araes

•&

■^

CHAPTER IX
CLIMATOLOGY OF THE PERUVIAN ANDES

CLIMATIC BELTS

The noble proportions of the Peruvian Andes and their posi-
tion in tropical latitudes have given them climatic conditions of
great diversity. Moreover, their great breadth and continuously
lofty summits have distributed the various climatic types over
spaces sufficiently ample to affect large and important groups of
people. When we add to this the fact that the topographic types
developed on a large scale are distributed at varying elevations,
and that upon them depend to a large degree the chief character-
istics of the soil, another great factor in human distribution, we
are prepared to see that the Peruvian Andes afford some strik-
ing illustrations of combined climatic and topographic control
over man.

The topographic features in their relations to the people have
been discussed in preceding chapters. We shall now examine the
corresponding effects of climate. It goes without saying that the
topographic and climatic controls cannot and need not be kept
rigidly apart. Yet it seems desirable, for all their natural inter-
dependence, to give them separate treatment, since the physical
laws upon which their explanations depend are of course entirely
distinct. Further, there is an independent group of human re-
sponses to detailed climati-! f^ures that have little or no connec-
tion with either topogiaphy or soil.

The chief climatic belts ol Peru run roughly from north to
south in the direction of the main features of the topography. Be-
tween 13° and 18° S., however, the Andes run from northwest to
southeast, and in short stretches nearly west-east, with the result
that the climatic belts like"\\'ise trend westward, a condition
well illustrated on the seventy-third meridian. Here are devel-

121

122 THE ANDES OF SOUTHERN PERU

oped importaut climatic features not found elsewhere in Peru.
The trade winds are greatly modified in direction and effects ; the
northward-trending valleys, so deep as to be secluded from the
trades, have floors that are nearly if not quite arid; a restricted
coastal region enjoys a heavier rainfall ; and the snowline is much
more strongly canted from west to east than anywhere else in the
long belt of mountains from Patagonia to Venezuela. These ex-
ceptional features depend, however, upon precisely the same phys-
ical laws as the normal climatic features of the Peruvian Andes.
They can, therefore, be more easily understood after attention has
been given to the larger aspects of the climatic problem of which
they form a part.

The critical relations of trade winds, lofty mountains, and
ocean currents that give distinction to Peruvian climate are shown
in Figs. 71 to 73. From them and Fig. 74 it is clear that the two
sides of the Peruvian mountains are in sharp contrast climatically.
I The eastern slopes have almost daily rains, even in the dry season,
' and are clothed with forest. The western leeward slopes are so
dry that at 8,000 feet even the most drought-resisting grasses
stop — only low shrubs live below this level, and over large areas
there is no vegetation whatever. An exception is the Coast
Eange, not shown on these small maps, but exhibited in the suc-
ceeding diagram. These have moderate rains on their seaward
(westerly) slopes during some years and grass and shrubby
vegetation grow Ix'lwccn llic nrid coasl.-il terraces below lliem
and llic i)ai'('li<'<l desert above. Tlie greatest variety of cliiiiate is
enjoyed by llie itiountaiii /one. Its (lee])er \alleys and l)asiiis de-
scend to tropical levels; its higher ranges and ])eaks are snow-cov-
ered. I>etween are the eliniates of half the world compressed, it
may be, Ix-tweeii <l,()()0 and If), 000 feet of elevation and with ex-
tremes only a (hiy's jonrney apai't.

In the explanation of these contrasts we have to deal with rela-
tively simple facts :in(l priiielples ; bill llie re.'ider wlut is interested
chiefly in tiie lnnnan aspects of tlie reirion should turn to p. ^'^P>
where the effects of tlie ejininte on ni;in ai'e set forth. The
ascending trades on the eastern .slopes pass successively into

CLIMATOLOGY OF THE PERUVIAN ANDES

123

Fig. 71.

Fig. 72.

WET ]/^S\i»;H[}mJf

%\ SEMI
■■'^\MOUNTAINS,

PLATEAUS AN Dc< ^
^^BASINSS^

Fig. 73.

Fig. 74.

Fig. 71 — The three chief topographic regions of Peru.

Fig. 72 — The wind belts of Peru and ocean currents of adjacent Avaters.

Fig. 73 — The climatic belts of Peru.

Fig. 74 — Belts of vegetation in Peru.

124- THE ANDES OF SOUTHERN PERU

atmospheric levels of diminisliing pressure; hence they expand,
deriving the required energy for expansion from the heat of
the air itself. The air thereby cooled has a lower capacity for
the retention of water vapor, a function of its temperature;
the colder the air the less water vapor it can take up. As~
long as the actual amount of water vapor in the air is less
fthan that which the air can hold, no rain falls. But the cool-
ing process tends constantly to bring the warm, moist, ascend-
ing air currents to the limit of their capacity for water vapor
by diminishing the temperature. Eventually the air is saturated
and if the capacity diminishes still further through diminishing
temperature some of the water vapor must be condensed from a
gaseous to a liquid form and be dropped as rain.

The air currents that rise thousands of feet per day on the
eastern slopes of the Andes pass again and again through this
practically continuous process and the eastern aspect of the moun-
tains is kept rain-soaked the whole year round. For the trades
here have only the rarest reversals. Generallj^ they blow from the
east day after day and repeat a fixed or average type of weather
peculiar to that part of the tropics under their steady domination.
During the southern summer, when the day-time temperature con-
trasts between mountains and plains are strongest, the force of
the trade wind is greatly increased and likewise the rapidity of the
rain-making processes. Hence there is a distinct seasonal differ-
ence in the rainfall — what we call, for want of a better name, a
"wet" and a "dry" season.

On the western or seaward slopes of the Peruvian Andes the
trade winds descend, and the process of rain-making is reversed
to one of rain-taking. The descending air currents are com-
pressed as they reach lower levels where there are progressively
higher atmospheric pressures. The energy expended in the proc-
ess is expressed in llic nil' as bent, wliciu'c llic (Icscciidiiiu- aii- gains
stondily in Iciiipci'ahii-c and capaciiy for water vapor, and there-
fore is a diying wind. Tims the leeward, western slopes of the
mountains roceivo little rain and the lowlands on that side are
desert.

CLIMATOLOGY OF THE PERUVIAN ANDES

125

THE CLIMATE OF THE COAST

A series of narrow but pronounced climatic zones coincide with
the topographic subdivisions of the western slope of the country
between the crest of the Maritime Cordillera and the Pacific Ocean.
This belted arrangement is diagrammatically shown in Fig. 75.
From the zone of lofty mountains with a well-marked summer
rainy season descent is made by lower slopes with successively

ZONE OF
COASTAL TER-
RACES

RAIN ONCE

IN MANY

YEARS

ZONEOF FOG-
COVERED MOUN-
TAINS

RAINAT INTER-
VALS OF 5-10
YEARS 5,(

00'

ZONE OF DESERT PLAINS

RAIN AT INTERVALS OF MANY YEARS

ZONEOFSTEEP

VALLEYS
YEARLY RAINS

ZONE OF LOFTY MOUNTAINS AND

PLATEAUS /-^^^la?!?;
FREQUENT RAINS IN^-^'d^^^^''^'^^^^

-PROFILE OF MAJES VALLEY

Fig. 75 — Topographic and climatic provinces in the coastal region of Peru. The
broadest division, into the zones of regular annual rains and of irregular rains, occurs
approximately at 8,000 feet but is locally variable. To the traveler it ia always clearly
defined by the change in architecture, particularly of the house roofs. Those of the
coast are flat; those of the sierra are pitched to facilitate run off.

less and less precipitation to the desert strip, where rain is only
known at irregular intervals of many years ' duration. Beyond lies
the seaward slope of the Coast Eange, more or less constantly
enveloped in fog and receiving actual rain every few^ years, and
below it is the very narrow band of dry coastal terraces.

The basic cause of the general aridity of the region has already
been noted ; the peculiar circumstances giving origin to the variety
in detail can be briefly stated. They depend upon the meteorologic
and hydrographic features of the adjacent portion of the South
Pacific Ocean and upon the local topography.

The lofty Andes interrupt the broad sweep of the southeast
trades passing over the continent from the Atlantic ; and the wind
circulation of the Peruvian Coast is governed to a great degree
by the high pressure area of the South Pacific. The prevailing
winds blow from the south and the southeast, roughly paralleling
the coast or, as onshore w^nds, making a small angle with it.
When the Pacific high pressure area is best developed (during the
southern winter), the southerly direction of the winds is empha-

126

THE ANDES OF SOUTHERN PERU

"^^

Air

Z..ry

■'Air 4p.m.

X/^

—

Sea 12a. m>^
Sea Sa.m."^^,

:>Sca 4p.m.

;\;^

"^"w

^-.

Air 8a.m.

■^^^

>^'^
~~^^--~

sized, a condition clearly shown on the Pilot Charts of the South
Pacific Ocean, issued by the U. S. Hydrographic Office.
/ The hydrographic feature of greatest importance is the Hum-
' boldt Current. To its cold waters is largely due the remarkably
low temperatures of the coast.' In the latitude of Lima its mean
JUNE JULY AUG. SEPT. surface temperature is about

10° below normal. Lima itself
has a mean annual tempera-
ture 4.6° F. below the theo-
retical value for that latitude,
"° (12° S.). An accompanying
curve shows the low tem-
16° perature of Callao during the
winter months. From mid-
June to mid-September the

16°

mean was 61° F., and the
annual mean is only 65.6° F.

Fig. 70 — Temperatures at Culluo, June-
September, 1912, from observations taken (18° C). The rcductioU in

by Captain A. Taylor, of Callao. Air tern- temperature is accompauicd by

peratures are shown by heavy lines; sea

temperatures by light lines. In view of a rcductioU in tllC Vapor CapaC-

the scant record for comparative land and .. ^^ ^^^ SUper-iuCUmbent air,

water temperatures along the Peruvian •'

coast tliis record, short as it is, has special an cffcct of wllicll mucll liaS

interest. \i(iQ.VL mado in explanati(5n of

the west-coast desert. That it is a contributing though not ex-
clusive factor is demonstrated in Kig. 77. Curve A represents
the hypothetical change of temperature on a mountainous coast
witli tt'iiiporary afternoon onshore winds from a irarm sea.
Curve JJ represents the change of temperninre il" llie sea be
cold factual case of Pern). 'I'lie more rai)i(l rise of curve B
to tlie riglit of X-X", llie line of 1 i-:insi1ion, and its higlier eleva-
tion above its foinifi- s;it nr;itioii le\-el, as coiil i-;is1e<l with A,
indicates grenter divness (h>\vei- i-eL'iti\-e linniidity). Tliere has

bcLii pfeelpll.'ilioli ill case A, hut ;il .-1 llighel- tellll)el-;itn|-e, lienCC

>Hann (TTnndbook of riimntoloKy. trnnHlnf^nl by R. P.- C Ward, Now York, 1903)
indicates a ronfributory cauHe in tlio upwcllinf; of en),! wnt.T .iloiif,' the coast caused
by the Htcady wcntorly drift, of fhc cqnatorinl riirniit.

CLIMATOLOGY OF THE PERUVIAN ANDES 127

more water vapor remains in the air after precipitation has
ceased. Curve B ultimately rises nearly to the level of A, for
with less water vapor in the air of case B the temperature rises
more rapidly (a general law). Moreover, the higher the tem-
perature the greater the radiation. To summarize, curve A rises
more slowly than curve B, (1) because of the greater amount
of water vapor it contains, which must have its temperature
raised with that of the air, and thus absorbs energy which would

70°

50°_
401
30 :

BELT OF FALLING TEMPERATURES BELT OF RISING TEMPERATURES,

CLOUD BANKS.HIGH DEW POINT CLEAR SKIES, LOW DEW POINT,

ANDMODERATEPRECIPITATION AND ARIDITY

SATURATION TEMPERATURE-
SATURATION TEMPERATURE-

I I
SEASHORE COAST RANGES DESERT

Fig. 77 — To show progressive lowering of saturation temperature in a desert under
the influence of the mixing process whereby dry and cool air from aloft sinks to lower
levels thus displacing the warm surface air of the desert. Tlie evaporated moisture of
the surface air is thus distributed through a great volume of upper air and rain becomes
increasingly rarer. Applied to deserts in general it shows that the effect of any
cosmic agent in producing climatic change from moist to dry or dry to moist will
be disproportionately increased. The shaded areas C and C represent the fog-covered
slopes of the Coast Range of Peru as shown in Fig. 92. X — X' represents the crest of
the Coast Range.

otherwise go to increase the temperature of the air, and (2) be-
cause its loss of heat by radiation is more rapid on account of its
higher temperature. We conclude from these principles and de-
ductions that under the given conditions a cold current intensi-
jaes, but does not cause the aridity of the west-coast desert.

Curves a and h represent the rise of temperature in two con-
trasted cases of. warm and cold sea with the coastal mountains
eliminated, so as to simplify the principle applied to A and B.
The steeper gradient of h also represents the fact that the lower
the initial temperature the dryer will the air become in passing
over the warm land. For these two curves the transition line
X-X' coincides mth the crest of the Coast Range. It will also be
seen that curve a is never so far from the saturation level as

128

THE ANDES OF SOUTHERN PERU

9 a.m.

DEC, JAN., 1897-1900

N
3 p.m.

8 a.m.

JUNE 11-SEPT. 11, 1912

N
Noon

Fia. 78 — Wind roses for Callao. Tlic figures for tlie onrlier pe-
riod (1H07-1900) lire drnwn from dnla in tli(! IJoIelfii dc la Sociediul
Geogrfificii de Limn, Vols. 7 and H, IKOH- 11)00: for tlie hiiU-v period
data from obscrvntions of ('a|)tiun A. Tiiyl'ir, of Callao. The diam-
eter of the circle reprosenlH the proiiortionat-i' niiniher of (jhservation.s
when calm was registered.

CLIMATOLOGY OF THE PERUVIAN ANDES

129

curve b. Hence, unusual atmospheric disturbances would result
in heavier and more frequent showers.

Turning now to local factors we find on the west coast a re-
gional topography that favors a diurnal periodicity of air move-
ment. The strong slopes of the Cordillera and the Coast Range
create up-slope or eastward air gradients by day and opposite

OCT.-MARCH, 1893-'95
2 p.m.

APRIL-SEPT., 1893- '95
2 p.m.

Fig. 79 — Wind roses for Mollendo. The figures are draAAii from data in Peruvian
Meteorology (1892-1895), Annals of the Astronomical Observatory of Harvard College,
Vol. 39, Pt. 2, Cambridge, Mass., 1906. Observations for an earlier period, Feb.
1869-March 1890, (Id. Vol. 39, Pt. 1, Cambridge, Mass. 1899) record S. E. wind at
2 p. m. 97 per cent of the observation time.

gradients by night. To this circumstance, in combination with
the low temperature of the ocean water and the direction of the
prevailing winds, is due the remarkable development of the sea-
breeze, without exception the most important meteorological fea-
ture of the Peruvian Coast. Several graphic representations are
appended to show the dominance of the sea-breeze (see wind roses

130

THE ANDES OF SOUTHERN PERU

for Callao, Mollendo, Arica, and Iquique), but interest in the
phenomenon is far from being confined to the theoretical. Every-
where along- the coast the virazon, as the sea-breeze is called in
contradistinction to the terral or land-breeze, enters deeply into
the affairs of human life. According to its strength it aids
or hinders shipping; sailing boats may enter port on it or it

7 a.m.

OCT.-MARCH

Fio. SO — Wind rosos for tlic suiniiu'r aiul winter seasons of the years 1!)11-1!>13.
The (iianu'ter of tlic circle in eaeli case shows the proi)orUon of calm. Figures are
drawn from data in tla- Anuario Meteorologico de Chile, Publications No. 3, (1911),
{V.)\-l) and 13 (Hil3), Santiago, 1912, 1!)14, 1!I14.

may be so x'iolciit, as, \i\v cxaiiiplc. it coiiiiiKUily is .-il I'isco,
tliat cai'go (•;iiiin)t he loiidcd oi- uiilondi'd diii-iiii;- ilic artci'iioon.
On the nitr;i1c |)aiii|.;i of iioi-tlicni Chile (I'd to 2.")' S. ) it not
iiirr<'<|Hcii1l\- l)rc;iks \\i1li a i-(i;ii- Ili;it lici-ahls its coiiiiiig an
hour ill ii(lv;iii(T. hi tlw Majcs \ alley ( TJ" S.) il blows gustily
for a lialt'lioiir mid mImdiI ikkhi (often by elexcn o'clock) it
settles down to an uiieomrorliihle gale. I^'oi" an hour or two

CLIMATOLOGY OF THE PERUVIAN ANDES

131

before the sea-breeze begins the air is hot and stifling, and
dust clouds hover about the traveler. The maximum tempera-
ture is attained at this time and not around 2,00 p. m. as is nor-
mally the case. Yet so boisterous is the noon wind that the laborers
time their siesta by it, and not by the high temperatures of earlier

OCT.-MARCH

N N . K

7 a.m.

2 p.m.

Fig. 81 — Wind roses for Iquique for the summer and winter seasons of the years
1911-1913. The diameter of the circle in each case shows the proportion of calm.
For source of data see Fig. 80.

hours. In the afternoon it settles down to a steady, comfortable^
and dustless wind, and by nightfall the air is once more calm.

Of highest importance are the effects of the sea-breeze on pre-
cipitation. The bold heights of the Coast Range force the nearly
or quite saturated air of the sea-wind to rise abruptly several
thousand feet, and the adiabatic cooling creates fog, cloud, and
even rain on the seaward slope of the mountains. The actual form
and amount of precipitation both here and in the interior region
vary greatly, according to local conditions and to season and also
from year to year. The coast changes height and contour from

132

THE ANDES OF SOUTHERN PERU

place to place. At Arica the low coastal chain of northern Chile
terminates at the Morro de Arica. Thence northward is a stretch
of open coast, with almost no rainfall and little fog. But in the
stretch of coast between Mollendo and the Majes Valley a coastal
range again becomes prominent. Fog enshrouds the hills almost
daily and practically every year there is rain somewhere along
their western aspect.

During the southern winter the cloud bank of the coast is best
developed and precipitation is greatest. At Lima, for instance,

EASTERiy WINDS fEEBU

RAINY SEASON

SEA BREEZE -^

DRY SEASON ,,-,--^^~^*^^^~~"

MARIIIMt MBOILURA-

HUH90LBICU»B£NT3J^!fOAST RANGE OESER

Fig. 82 — The wet and dry seasons of
the Coast Range and the Cordillera are
complementary in time. The " wet "
season of the former occurs during the
southern winter; the cloud bank on the
seaward slopes of the hills is best devel-
oped at that time and actual rains may
occur.

EASTEBLY WINOSATHIGH ELEVATION

DRY SEASON

SEA BREEZE

-'sei,^^

HlJMBOLDT CUI

Fig. 83 — During the southern summer
the seaward slopes of the Coast Range are
comparatively clear of fog. Afternoon
cloudiness is characteristic of the desert
and increases eastward (compare Fig.
86), the influence of the strong sea winds
as well as that of the trades (compare
Fig. 93B) being felt on the lower slopes
of the Maritime Cordillera.

the clear skies of March and April begin to be clouded in May, and
the cloudiness grows until, from late June to September, the sun
is invisible for weeks at a time. This is the period of the garua
(mist) or the ^'tiempo de lomas," the "season of the hills," when
the moisture clothes them with verdure and calls thither the herds
of the coast valleys.

During the southern summer on account of the greater relative
/differenec between the temperatures of land and water, the sea-
breeze attains its maximum strength. It then accomplishes its
greatest work in the desert. On the pampa of La Joya, for exam-
ple, the sand dunes move most rapidly in the summer. According
to the Peruvian Meteorological Records of the Harvard Astronom-
ical Observatory the average movement of the dunes from April
to September, 1900, was 1.4 inches per day, while during the sum-
mer months of the same year it was 2.7 inches. In close agree-
ment are the figures for the wind force, the record for which also

CLIMATOLOGY OF THE PERUVIAN ANDES

133

June, July

Dec, Jan.

9 a.m.

3 p.m.

shows that 95 per cent of the winds with strength over 10 miles per
hour blew from a southerly direction. Yet during this season the
coast is generally clearest of fog and cloud. The explanation ap-
pears to lie in the exceedingly delicate nature of the adjustments
between the various rain-making forces. The relative humidity
of the air from the sea is al-
ways high, but on the im-
mediate coast is slightly less
so in summer than in win-
ter. Thus in Mollendo the
relative humidity during the
winter of 1895 was 81 per
cent; during the summer 78
per cent. Moreover, the
temperature of the Coast
Range is considerably higher
in summer than in winter,
and there is a tendency to
reevaporation of any mois-
ture that may be blown
against it. The immediate
shore, indeed, may still be
cloudy as is the case at Cal-
lao, which actually has its
cloudiest season in the sum-
mer, but the hills are com-
paratively clear. In conse-
quence the sea-air passes
over into the desert, w^here
the relative increase in tem-
perature has not been so
great (compare Mollendo and La Joya in the curve for mean
monthly temperature), with much higher vapor content than in
winter. The relative humidity for the winter season at La Joya,
1895, was 42.5 per cent; for the summer season 57 per cent. The
influence of the great barrier of the Maritime Cordillera, aided

9p.m.

jjCompletely
3 Overcast

Scale of Cloudiness

[IZl Clear EH 0-2.5 ES3 2.5-7.5 ^9.5-10

Fig. 84 — Cloudiness at Callao. Figures
are drawn from data in the Boletfn de la
Sociedad Geognlfica de Lima, Vols. 7 and 8,
1898-1900. They represent the conditions at
three observation hours during the summers
(Dec., Jan.) of 1897-1898, 1898-1899, 1899-
1900 and the winters (June, July) of 1898 and
1899.

13i

THE ANDES OF SOUTHERN PERU

doubtless by convectional rising, causes ascent of the compara-
tively humid air and the formation of cloud. Farther eastward,
as the topographic influence is more strongly felt, the cloudiness

1894 1895

Fig. So — Temperature curves for Mollendo (solid lines) and La Joya (broken
lines) April, 1894, to December, 1895, drawn from data in Peruvian Meteorology, 1892-
1895, Annals of the Astronomical Observatory of Harvard College, Vol. 49, Pt. 2,
Cambridge, Mass., 1908. The approximation of the two curves of maximum tempera-
ture during the winter months contrasts with the well-maintained difference in minimum
temperatures througliout the year.

increases until on the border zone, about 8,000 feet in elevation, it
may thicken to actual rain. Data have been selected to demon-
strate this eastern gradation of meteorological phenomena.

1892 1893 1894 1895 „ . .

A M

"Jl

A S

"^1

"ijI

[7]

AIS

J A S

N D

c»u

WINTER

SUMMER

INI

SUM

MER

NTER

SUMMER

TER

8
7
6
6
4
8

--.

.Mollor

<i(

}

•^

I Jcja

/■

•f

'^4

.•*

■

"■

•-

■ •

«-

-■

Via. HCt — Mean monthly cloudiness for Mollendo (solid line) and T.a Joya (broken
line) from April, 1H92, to DeccmlKT, 1H95. Mollendo, 80 feet elevation, lias the maximum
winU'r cloudincHs characteristic of the seaward slope of the Coast Range (compare
Fig. 82) wliile the desert station of T^a Joya, 4,140 feet elevation, has typical summer
cloudiness (compare Fig. 8.3). Figurea are drawn from data in Peruvian Meteorology',
1892-1895, Annals of the Astronomical Observatory of Harvard Colb-gc, Vol. 49. Pt. 2,
Canibridgi-, Mass., 1908.

At Ija Joya, a station on the desert nortlieast of Molk'ndo at
an elevation of 4,140 feet, cloudiness is always slight, but it in-
creases markedly during Iho siiiiiincr. Onniveli, ;i< ;iii altitude of

CLIMATOLOGY OF THE PERUVIAN ANDES

135

5,635 feet,'' and near the eastern border of the pampa, exhibits a
tendency toward the climatic characteristics of the adjacent zone.
Data for a camp station out on the pampa a few leagues from
the town, were collected by Mr. J. P. Little of the staff of the

8 a.m

2 p.m.

8 p.m.

Fig. 87 — Wind roses for La Joya for the period April, 1892, to December, 1895.
Compare the strong afternoon indraught from tlie south with the same plienomenon
at Mollendo, Fig. 79. Figures drawn from data in Peruvian Meteorology, 1892-1895,
Annals of the Astronomical Observatory of Harvard College, Vol. 39, Pt. 2, Cambridge,
Mass., 1906.

Peruvian Expedition of 1912-13. They relate to the period
January to March, 1913. Wind roses for these months show the
characteristic light northwesterly winds of the early morning
hours, in sharp contrast with the strong south and southwesterly
indraught of the afternoon. The daily march of cloudiness is
closely coordinated. Quotations from Mr. Little's field notes fol-
low:

"In the morning there is seldom any noticeable wind. A
breeze starts at 10 a. m., generally about 180° (i. e. due south),
increases to 2 or 3 velocity at noon, having veered some 25" to the
southwest. It reaches a maximum velocity of 3 to 4 at about 4.00
p. M., now coming about 225° (i. e. southwest). By 6 p. m. the wind

' This is the elevation obtained by the Peruvian Expedition. Raimondi's figure
(1,832 m.) is higher.

136

THE ANDES OF SOUTHERN PERU

has died down considerably and the evenings are entirely free
from it. The wind action is about the same- every day. It is not
a cold wind and, except with the fog, not a damp one, for I have
not worn a coat in it for three weeks. It has a free unobstructed
sweep across fairly level pampas. ... At an interval of every
three or four days a dense fog sweeps up from the southwest,
dense enough for one to be easily lost in it. It seldom makes even

Fio. 88 — Wind roses for a station on the eastern border of the Coast Desert near
Caraveli during the summer (January to Marcli) of 1913. Compare witli Fig. 87.
The diameter of the circle in each case represents the proportion of cahn. Note the
characteristic morning calm.

a sprinkle of rain, but carries heavy moisture and will wet a man
on horseback in 10 minutes. It starts about 3 p. m. and clears
away by 8.00 p. :m. . . . During January, rain fell in camp twice
on successive days, starting at 3.00 p. m. and ceasing at 8.00 p. m.
It was merely a light, steady rnin, more ilie outcome of a dense
fog than a rain-cloud of quick ai)proach. In Caraveli, itself, I am
told \hi\i it r.'iins off and on nil during the month in short, light
showers." This record is dated early in February and, in later
notes, that month and March are recorded rainless.

Chosica (elevation (nGOO feet), one of the meteorological sta-
tions of the Harvard Astronomical Observatory, is still nearer the

CLIMATOLOGY OF THE PERUVIAN ANDES

137

border. It also lies farther north, approximately in the latitude
of Lima, and this in part may help to explain the greater cloudi-
ness and rainfall. The rainfall for the year 1889-1890 was 6.14
inches, of which 3.94 fell in February. During ihe winter months
when the principal wind observations were taken, over 90 per cent
showed noon Avinds from a southerly direction while in the early

6 p.m.

Cloudiness

Completely
Overcast

[ZH Clear EH 0-2.5 E^ 2.5-7.5 WM 7.5-10

Fig. 89 — Cloudiness at the desert station of Fig. 88 (near Caraveli), for the
summer (January to March) of 1913.

morning northerly winds were frequent. It is also noteworthy
that the "directions of the upper currents of the atmosphere as
recorded by the motion of the clouds was generally between N. and
E. ' ' Plainly we are in the border region where climatic influences
are carried over from the plateau and combine their effects with
those from Pacific sources. Arequipa, farther south, and at an
altitude of 7,550 feet, resembles Chosica. For the years 1892 to
1895 its mean rainfall was 5Jc inches.

Besides the seasonal variations of precipitation there are
longer periodic variations that are of critical importance on the
Coast Range. At times of rather regular recurrence, rains that
are heavy and general fall there. Every six or eight years is said
to be a period of rain, but the rains are also said to occur some-
times at intervals of four years or ten years. The regularity is
only approximate. The years of heaviest rain are commonly as-
sociated with an unusual frequency of winds from the north, and
an abnormal development of the warm current. El Nino, from the

138

THE ANDES OF SOUTHERN PERU

Scale of
Cloudicess

18S9 1890

JASONDJFMAMJ JAS

■ I ' I

WINTER

■ 1 1

SUMMER

•\

•

\ N

;

V
\

;

..'■

1
/

;7pr

Tl.,.

.-^

•^

^/'

iur

\3.\\

nca

■-s

llja-m

^■^

Gulf of Gruayaquil. Such was the case in the phenomenally rainy

year of 1891. The connection is obscure, but undoubtedly exists.

The effects of the heavy rains are amazing and appear the

more so because of the extreme aridity of the country east of

them. During the mnter
the desert traveler finds the
air temperature rising to
uncomfortable levels. VegCr
tation of any sort may be
completely lacking. As he
approaches the leeward
slope of the Coast Range, a
cloud mantle full of refresh-
ing promise may be seen
just peeping over the crest
(Fig. 91). Long, slender
cloud filaments project east-
ward over the margin of the
desert. They are traveling
rapidly but they never ad-
vance far over the hot
wastes, for their eastern
margins are constantly un-
dergoing evaporation. At times the top of the cloud bank rises
well above the crest of the Coast Range, and it seems to the man
from the temperate zone as if a great thunderstorm were rising in
the west. But for all their menace of wind and rain the clouds
never got beyond the desert outposts. In the summer season the
aspect changes, the heavy yellow sky of the desert displaces the
murk of the coastal mountains and the bordering sea.

It is an age-old strife ronewod every year and limited to a nar-
row fifld of .'icfion, woiidcrfiilly cnsy to observe. We saw it in its
most striking form ni Iho cud of 1ho winter season in October,
1911, and for more tli.-in a d;iy watched tlie dark clouds rise omi-
nously only to melt into nothing where tho desert liolds swny. At
night we camped beside a scum-coated i)ool of alkali water no

FiQ. 90 — Cloudiness at Chosica, July, 1889,
to September, 1890. Chosica, a station on
the Oroya railroad east of Lima, is situated
on the border region between the desert zone
of the coast and the mountain zone of yearly
rains. The minimum cloudiness recorded about
11 a. m. is shown by a broken line; the maxi-
mum cloudiness, about 7 p. m., by a dotted
line, and the mean for the 24 hours by a heavy
solid line. The curves are drawn from data
in Peruvian Mctcorologj', 1889-1890, Annals
of the Astronomical Observatory of Harvard
College, Vol. 39, Pt. 1, Cambridge, Mass., 1899.

CLIMATOLOGY OF THE PERUVIAN ANDES 139

larger than a wash basin. It lay in a valley that headed in the
Coast Range, and carried down into the desert a mere trickle that
seeped through the gravels of the valley floor. A little below the
pool the valley cuts through a mass of granite and becomes a steep-
walled gorge. The bottom is clogged with waste, here boulders,
there masses of both coarse and fine alluvium. The water in the
valley was quite incapable of accomplishing any work except that
associated with solution and seepage, and we saw it in the wet
season of an unusually wet year. Clearly there has been a diminu-
tion in the water supply. But time prevented us from explor-
ing this particular valley to its head, to see if the reduction
were due to a change of climate, or only to capture of the
head-waters by the vigorous rain-fed streams that enjoy a favora-
ble position on the wet seaward slopes and that are extending
their watershed aggressively toward the east at the expense of
their feeble competitors in the dry belt^^

An early morning start enabled me to witness the whole series
of changes between the clear night and the murky day, and to pass
in twelve hours from the dry desert belt through the wet belt, and
emerge again into the sunlit terraces at the western foot of the
Coast Range. Two hours before daylight a fog descended from
the hills and the going seemed to be curiously heavy for the beasts.
At daybreak my astonishment was great to find that it was due
to the distinctly moist sand. We were still in the desert. There
was not a sign of a bush or a blade of grass. Still, the surface
layer, from a half inch to an inch thick, was really wet. The fog
that overhung the trail lifted just before sunrise, and at the first
touch of the sun melted away as swiftly as it had come. With it
went the surface moisture and an hour after sunrise the dust was
once more rising in clouds around us.

We had no more than broken camp that morning when a
merchant with a pack-train passed us, and shouted above the
bells of the leading animals that we ought to hurry or we should
get caught in the rain at the pass. My guide, who, like many of
his kind, had never before been over the route he pretended to
know, asked him in heaven's name what drink in distant Camana

140 THE ANDES OF SOUTHERN PERU

whence he had come produced such astonishing effects as to make
a man talk about rain in a parched desert. We all fell to laugh-
ing and at our banter the stranger stopped his pack-train and
earnestly urged us to hurry, for, he said, the rains beyond the pass
were exceptionally hea^y this year. We rode on in a doubtful
state of mind. I had heard about the rains, but I could not be-
lieve that they fell in real showers !

About noon the cloud bank darkened and overhung the border
of the desert. Still the sky above us was clear. Then happened
what I can yet scarcely believe. We rode into the head of a tiny
valley that had cut right across the coast chain. A wisp of cloud,
an outlier of the main bank, lay directly ahead of us. There
were grass and bushes not a half-mile below the bare dry spot on
which we stood. We were riding down toward them when of a
sudden the wind freshened and the cloud wisp enveloped us, shut-
ting out the view, and ten minutes later the moisture had gath-
ered in little beads on the manes of our beasts and the trail be-
came slippery. In a half-hour it was raining and in an hour we
were in the midst of a heavy doAvnpour. We stopped and pas-
tured our famished beasts in luxuriant clover. While they gorged
themselves a herd of cattle drifted along, and a startled band of
burros that suddenly confronted our beasts scampered out of sight
in the heavy mist. Later we passed a herdsman's hut and long
before wo reached him he shouted to us to alter our course, for
just ahead the old trail was wet and treacherous at this time
of year. The warning came too late. Several of our beasts lost
their footing and half rolled, half slid, down hill. One turned com-
pletely over, pack and all, and lay in the soft mud calmly taking
advantage of the delay to pluck a few additional mouthfuls of
grass. We were glad to reach firmer ground on the other side of
tlic \-;illey.

The herdsmen were a hospitable h)t. Thoy lind come from
Camana and rarely saw travelers. Their single-roomed hut was
mired so deojily Hint one found it hard to decide whether to take
shelter from tlic rain inside or escape the mud by standing in the
rain outside. They made a little so-called cheese, rounded up and

CLIMATOLOGY OF THE PERUVIAN ANDES 141

counted the cattle on clear days, drove them to the springs from
time to time, and talked incessantly of the wretched rains in the
hills and the delights of dry Camana down on the coast. We could
not believe that only some hours' traveling separated two locali-
ties so wholly unlike.

The heavy showers and luxuriant pastures of the wet years
and the light local rains of the dry years endow the Coast Eange
with many peculiar geographic qualities. The heavy rains pro-
vide the desert people at the foot of the mountains such a wealth
of pasture for their burdensome stock as many oases dwellers
possess only in their dreams. From near and far cattle are driven
to the wet hill meadows. Some are even brought in from distant
valleys by sea, yet only a very small part of the rich pastures can
be used. It is safe to say that they could comfortably support ten
times the number of cattle, mules, and burros that actually graze
upon them. The grass would be cut for export if the weather
were not so continually wet and if there were not so great a mix-
ture of weeds, flowers, and shrubs.

Then come the dry years. The surplus stock is sold, and what
remains is always maintained at great expense. In 1907 I saw
stock grazing in a small patch of dried vegetation back of Mol-
lendo, although they had to be driven several miles to water. They
looked as if they were surviving with the greatest difficulty and
their restless search for pasture was like the search of a desper-
ate hunter of game. In 1911 the same tract was quite devoid of
grass, and except for the contour-like trails that completely cov-
ered the hills no one would even guess that this had formerly been
a cattle range. The same year, but five months later, a carpet
of grass, bathed in heavy mist, covered the soil; a trickle of water
had collected in pools on the valley floor ; several happy families
from the town had laid out a prosperous-looking garden; there
were romping children who showed me where to pick up the trail
to the port ; on every hand was life and activity because the rains
had returned bringing plenty in their train. I asked a native how
often he was prosperous.

"Segun el temporal y la Providencia" (according to the

142 THE ANDES OF SOUTHERN PERU

weather and to Providence), he replied, as he pointed significantly
to the pretty green hills crowned with gray mist.

It, therefore, seems fortunate that the Coast Range is so placed
as to intercept and concentrate a part of the moisture that the sea-
winds carry, and doubly fortunate that its location is but a few
miles from the coast, thereby giving temporary relief to the rela-
tively crowded people of the lower irrigated valleys and the towns.
The wet years formerly developed a crop of prospectors. Pack
animals are cheaper when there is good pasture and they are also
easier to maintain. So when the rains came the hopeful pick-and-
shovel amateurs began to emigrate from the to\\Tis to search for
ore among the discolored bands of rock intruded into the granite
masses of the coastal hills. However, the most likely spots have
been so thoroughly and so unsuccessfully prospected for many
years that there is no longer any interest in the "mines."

Transportation rates are still most intimately related to the
^rains. My guide had two prices — a high price if I proposed to
enter a town at night and thus require him to buy expensive
forage ; a low price if I camped in the hills and reached the town
in time for him to return to the hills with his animals. Inquiry
showed that this was the regular custom. I also learned that in
packing goods from one part of the coast to another forage must
be carried in dry years or the beasts required to do without.
In wet years by a very slight detour the packer has his boasts in
good pasture that is free for all. The merchant who dispatches
the goods may find his charges nearly doubled in extremely dry
years. Ooods are more expensive and there is a decreased con-
sumption. 'I'lic effects of the rains are thus transmitted from one
to another, uiilil at last nearly all the inoiii])ers of a community
are l)cariiig a share of 11i<' hiirdciis iiiiijoscd ])y drought. As al-
ways there are a few who prosper in spite of the ill wind. If the
pasturfjs fail, live stock must be sold and the dealers ship south
to the nitrate ports or north fo the largo coast towns of Peru,
where there is always a demand. 'J'hoir business is most active
when it is dry or rather at the beginning of the dry period. Also
if transport by land routes becomes too expensive the small trad-

CLIMATOLOGY OF THE PERUVIAN ANDES 143

ers turn to the sea routes and the carriers have an increased busi- J
ness. But so far as I have been able to learn, dry years favor
only a few scattered individuals.

To the traveler on the west coast it is a source of constant sur-
prise that the sky is so often overcast and the ports hidden by fog,
while on every hand there are clear evidences of extreme aridity.
Likewise it is often inquired why the sunsets there should be often
so superlatively beautiful during the winter months when the
coast is fog bound. Why a desert when the air is so humid? Why
striking sunsets when so many of the days are marked by dull
skies ? As we have seen in the first part of this chapter, the big
desert tracts lie east of the Coast Bange, and there, excepting
slight summer cloudiness, cloudless skies are the rule. The des-
ert just back of the coast is in many parts of Peru only a narrow
fringe of dry marine terraces quite unlike the real desert in type
of weather and in resources. The fog bank overhanging it
forms over the Humboldt Current which lies off shore; it drifts
landward with the onshore wind ; it forms over the up welling cold
water between the current and the shore; it gathers on the sea-
ward slopes of the coastal hills as the inflowing air ascends them
in its journey eastward. Sometimes it lies on the surface of the
land and the water; more frequently it is some distance above
them. On many parts of the coast its characteristic position is
from 2,000 to 4,000 feet above sea level, descending at night nearly
or quite to the surface, ascending by day and sometimes all but
disappearing except as rain-clouds on the hills.^ Upon the local
behavior of the fog bank depends in large measure the local cli-
mate. A general description of the coastal climate will have many

• According to Ward's observations the base of the cloud belt averages between
2,000 and 3,000 feet above sea level (Climatic Notes Made During a Voyage Around
South America, Journ. of School Geogr., Vol. 2, 1898). On the south Peruvian coast,
specifically at Mollendo, Middendorf found the cloud belt beginning about 1,000 feet
and extending upwards to elevations of 3.000 to 4,000 feet. At Lima the clouds descend
to lower levels (El Clima de Lima, Bol. Soc. Geogr. de Lima, Vol. 15, 1904). In
the third edition of his Sud- und Mittolaracrika (Leipzig and Vienna, 1914) Sievers
Bays that at Lima in the winter the cloud on the coast does not exceed an elevation
of 450 m. (1,500 feet) while on the hills it lies at elevations between 300 and 700 m.
(1,000 and 2,300 feet).

lU THE ANDES OF SOUTHERN PERU

exceptions. The physical principles involved are, however, the
same everywhere. I take for discussion therefore the case illus-
trated by Fig. 92, since this also displays with reasonable fidelity
the conditions along that part of the Peruvian coast between
Camana and Mollendo which lies in the field of work of the Yale
Peruvian Expedition of 1911.

Three typical positions of the fog bank are shown in the figure,
and a fourth — that in which the bank extends indefinitely west-
ward — may be supplied by the imagination.

If the cloud bank be limited to C only the early morning hours
at the port are cloudy. If it extend to B the sun is obscured until
midday. If it reach as far west as A only a few late afternoon
hours are sunny. Once in a while there is a sudden splash of rain
-—a few drops which astonish the traveler who looks out upon a
parched landscape. The smaller drops are evaporated before
reaching the earth. In spite of the ever-present threat of rain the
coast is extremely arid. Though the vegetation appears to be
dried and burned up, the air is humid and for months the sky may
be overcast most of the time. So nicely are the rain-making con-
ditions balanced that if one of our ordinary low-pressure areas,
or so-called cyclonic storms, from the temperate zone Avere set in
motion along the foot of the mountains, the resulting deluge would
immediately lay the coast in ruins. The cane-thatched, mud-
walled huts and houses would crumble in the heavy rain like a
child's sand pile before a rising sea; the alluvial valley land would
be coated with infertile gravel; and mighty rivers of sand, now
delicately poised on arid slopes, would iiumdato large tracts of
fertile soil.

If the fog and cloud bank extend westward indefinitely, the en-
tire day may be overcast or the sun appear for a few moments
only through occasional rifts. Generally, also, it will make an ap-
pearance just before sunset, its red disk completely filling the nar-
row space between the under surface of the clouds and the Avater.
I have repeatedly seen the ship's passengers and even the crew
leave the dinner table and collect in wondering groups about the
port-holes and doorways the better to see the marvelous play of

Fig. 91.

ZDNEOFCOASTALTERRACES

DRY UNDERNEATH FOG-BANK

FOG-BANK BETWEEN 2,000 ANO 4,1)1111 IK

ZONE OFSUBDUED COASTAL MOUNTAINS

WET SEAWARD ASPECT DRY LANDWARD ASPECT

DESERT ZONE

lyPES OF STREAM Profiles

Fig. 92.

Fig. 91 — Looking clown the canyon of the IMajes River to the edge of the cloud
bank formed against the Coast Range back of Camana.

Fig. 92 — Topographic and climatic cross-section to show the varying positions of
the cloud bank on the coast of Peru, the dry terrace region, and the types of stream
profiles in the various belts.

CLIMATOLOGY OF THE PERUVIAN ANDES 145

colors between sky and sea. It is impossible not to be profoundly
moved by so majestic a scene. A long resplendent path of light
upon the water is reflected in the clouds. Each cloud margin is
tinged with red and, as the sun sinks, the long parallel bands of
light are shortened westward, changing in color as they go, until
at last the full glory of the sunset is concentrated in a blazing arc
of reds, yellows, and purples, that to most people quite atones for
the dull gray day and its humid air.

At times the clouds are broken up by the winds and scattered
helter-skelter through the west. A few of them may stray into
the path of the sun temporarily to hide it and to reflect its pri-
mary colors when the sun reappears. From the main cloud masses
there reach out slender wind-blown streamers, each one delicately
lighted as the sun's rays filter through its minute water particles.
Many streamers are visible for only a short distance, but when
the sun catches them their filmy invisible fingers become delicate
bands of light, some of which rapidly grow out almost to the dome
of the sky. Slowly they retreat and again disappear as the rays
of the sun are gradually shut off by the upturning curve of the
earth.

The unequal distribution of precipitation in the climatic zones
of western Peru has important hydrographic consequences. These
will now be considered. In the preceding figure four types of
stream profiles are displayed and each has its particular relation
to the cloud bank. Stream 1 is formed wholly upon the coastal
terraces beneath the cloud bank. It came into existence only
after the uplift of the earth 's crust that brought the wave-cut plat-
forms above sea level. It is extremely youthful and on account
first of the small seepage at its headquarters — it is elsewhere
wholly without a tributary water supply — and, second, of the re-
sistant granite that occurs along this part of the coast, it has very
steep and irregular walls and an ungraded floor. Many of these
''quebradas" are difficult to cross. A few of them have fences
built across their floors to prevent the escape of cattle and burros
that wander down from the grassy hills into the desert zone.
Others are partitioned off into corrals by stone fences, the steep

146 THE ANDES OF SOUTHERN PERU

walls of the gorge preventing the escape of the cattle. To these
are driven the market cattle, or mules and burros that are re-
quired for relays along the shore trail.

^ Stream 2 heads in the belt of rains. Furthermore it is a much
older stream than 1, since it dates back to the time when the Coast
Kange was first formed. It has ample tributary slopes and a large
number of small valleys. A trickle of water flows down to become
lost in the alluvium of the lower part of the valley or to reappear
in scattered springs. AYhere springs and seepage occur together,
an olive grove or a garden marks the spot, a corral or two and a
mud or stone or reed hut is near by, and there is a tiny oasis.
Some of these dots of verdure become so dry during a prolonged
drought that the people, long-established, move away. To others
the people return periodically. Still others support permanent
settlements.

^y Stream 3 has still greater age. Its only competitors are the
feeble, almost negligible, streams that at long intervals flow east
toward the dry zone. Hence it has cut back until it now heads in
the desert. Its widely branched tributaries gather moisture from
large tracts. There is running water in the valley floor even down
in the terrace zone. At least there are many dependable springs
and the permanent homes that they always encourage. A valley
of this type is always marked by a well-defined trail that leads
from settlement to settlement and eastward over the "pass" to
the desert and the Andean towns.

'^Stream 4 is a so-called "antecedent" stream. It existed be-
fore the Coast Range was uplifted and cut its channel downward
as the mountains rose in its path. The stretch where it crosses
the mountains may be a canyon with a narrow, rocky, and unculti-
vable floor, so that the valley trails rise to a pass like thnt at the
head of stream 3, and descend again to tlie settlements at the
moutli of 4. There is in this last type an abundance of water, for
tlie sources of the stream are in tlie zone of pei-mnnent snows and
frequent winter rains of the lofty Cordillera of the Andes. The
settlements along this stream are continuous, except where shut-
ins occur — narrow, rocky defiles caused by more resistant rock

CLIMATOLOGY OF THE PERUVIAN ANDES 147

masses in the path of the stream. Here and there are villages.
The streams have fish. AVhen the water rises the river may be
unfordable and people on opposite sides must resort to boats or
rafts.*

EASTERN BOEDER CLIMATES

On windward mountain slopes there is always a belt of maxi-
mum precipitation whose elevation and width vary with the"]
strength of the wind, with the temperature, and with the topog-
raphy. A strong and constant wind will produce a much morej
marked concentration of the rainfall. The belt is at a low eleva-
tion in high latitudes and at a high elevation in low latitudes, with
many irregularities of position dependent upon the local and espe-
cially the minimum winter temperature. _The topographic con-
trols_arejmportant, since the rain-compelling elevation may scat-
ter widely the localities of maximum precipitation or concentrate
them within extremely narrow limits. The human effects of these
climatic conditions are manifold. Wherever the heaviest rains
are, there, too, as a rule, are the densest forests and often the
most valuable kinds of trees. If the general climate be favorable
and the region lie near dense and advanced populations, exploita-
tion of the forest and progress of the people will go hand in hand.
If the region be remote and some or all of the people in a primi-
tive state, the forest may hinder communication and retard devel-
opment, especially if it lie in a hot zone where the natural growth
of population is slow. . . . These are some of the considerations
we shall keep in mind while investigating the climate of the east-
ern border of the Peruvian Andes.

The belt of maximum precipitation on the eastern border of
the Andean Cordillera in Peru lies between 4,000 and 10,000 feet.
Judging by the temporary records of the expedition and especially

* In most of the coast towns the ford or ferry is an important institution and the
chimhadores or laleadores as they are called are expert at their trade: they know
the regime of the rivers to a nicety. Several settlements owe their origin to the
exigencies of transportation, permanent and periodic; thus before the development of
its irrigation system Camana, according to General ^Miller (^Memoirs, London, 1829,
Vol. 2, p. 27), was a hamlet of some 30 people who gained their livelihood through
ferrying freight and passengers across the ]\Iajes River.

148

THE ANDES OF SOUTHERN PERU

by the types of forest growth, the heaviest rains occur around
8,000 feet. It is between these elevations that the densest part
of the Peruvian montana (forest) is found. The cold timber line
is at 10,500 feet with exceptional extensions of a few species to

ZONEOFLIGHT RAIN AND LOCALSNOW ZONE OF MAXIMUM RAINFALL

DRY AND WET SEASONS SHARPLY
MARKED AND EQUAL IN LENGTH

lONE WELL-MARKED SHORT DRY
i SEASON

ZONE OF MODERATE RAINFALL
ONE WELL-MARKED LONG DRY
SEASON

Fig. 93A — Cloud types and rainfall belts on the eastern border of the Peruvian Andes
in the dry season, southern winter. The zone of maximum rainfall extends approxi-
mately from 4,000 to 10,000 feet elevation.

12,500 feet. In basins or deep secluded valleys near the moun-
tain border, a dry timber line occurs at 3,000 feet with many varia-
tions in elevation due to the variable declivity and exposure of the
slopes and degree of seclusion of the valleys. Elsewhere, the

TRADES FEEBLER ; LOCAL INFLU-
ENCES STRONG

; TRADES REINFORCED BY STRONG UP-;
I VALLEY WINDS BY DAYAND NEUTRAL7
1 IZEO BY MODERATE DOWN-VALLEYi
:;r^LV^^^^,NDSBYNIGHT

NORMAL TRADES

FiQ. i)3B — Cloud types and rainfall belts on the oastorn border of the renivian
Andes in the wet season, southern summer.

mountain forest passes without a break into tlie i^lains forest with
change in type but with little change in density. The procumbent
niid siiiiprcsscd I i-fos of Iho cold tiiiihci- line in rcgioiis of heavy
winter snows are here absent, for the snows rarely reach below
14,000 feet and even at that elevation they are only light and tem-
porary. The lino of perpetual snow is at 15,000 feet. This
permanent gap of several thousand feet vertical elevation between
the zone of snow and the zone of forest permits the full extension
of many pioneer forest species, wliich is to say, tlicrc is an irregu-

CLIMATOLOGY OF THE PERUVIAN ANDES 149

lar development of the cold timber line. It also permits the full
use of the pasture belt above the timber (Fig. 97), hence perma-
nent habitations exist but little below the snowline and a group
of distinctive high-mountain folk enjoys a wide distribution.
There is a seasonal migration here, but it is not wholesale ; there
are pastures snow-covered in the southern winter, but, instead of
the complete winter burial of the Alpine meadows of our western
mountains, we have here only a buried upper fringe. All the rest
of the pasture belt is open for stock the year round.

This climatic distinction between the lofty grazing lands of the \
tropics and those of the temperate zones is far-reaching. Our
mountain forests are not utilized from above but from below.
Furthermore, the chief ways of communication lead around our
forests, or, if through them, only for the purpose of putting one
population group in closer touch with another. In the Peruvian /
Andes the largest population groups live above the forest, not be-
low it or within it. It must be and is exploited from above.

Hence railways to the eastern valleys of Peru have two chief
objects, (1) to get the plantation product to the dense populations
above the forest and (2) to bring timber from the montana to the
treeless plateau. The mountain prospector is always near a habi-
tation; the rubber prospector goes down into the forested valleys
and plains far from habitations. The forest separates the naviga-
ble streams from the chief towns of the plateau; it does not lead
down to rich and densely populated valley floors.

Students in eastern Peru should find it a little difficult to
understand poetical allusions to silent and lonely highlands in con-
trast to the busy life of the valleys. To them Shelley's descrip-
tion of the view from the Euganean Hills of northern Italy,

" Beneath is spread like a green sea
The waveless plain of Lombardy, . . .
Islanded by cities fair,"

might well seem to refer to a world that is upside down.

There is much variation in the forest tjT3es between the moun-
tains and the plains. At the top of the forest zone the warm

150 THE ANDES OF SOUTHERN PERU

sunny slopes have a forest cover; the shady slopes are treeless.
At the lower edge of the grassland, only the shady slopes are for-
ested (Fig. 53B). Cacti of arboreal size and form grow on the
lofty mountains far above the limits of the true forest; they also
appear at 3,000 feet in modified form, large, rank, soft-spined, and
in dense stands on the semi-arid valley floors below the dry timber
line. Large tracts between 8,000 and 10,000 feet are covered with
a forest growth distributed by species — here a dense stand of one
type of tree, there another. This is the most accessible part of
the Peruvian forest and along the larger valleys it is utilized to
some extent. The number of species is more limited, however, and
the best timber trees are lower down. Though often referred to
as jungle, the lowlier growths at the upper edge of the forest zone
have no resemblance to the true jungle that crowds the lowland
forest. They are merely an undergrowth, generally open, though
in some places dense. They are nowhere more dense than many
examples from New England or the West.

Where deep valleys occur near the border of the mountains
there is a semi-arid climate below and a wet climate above, with a
correspondingly greater number of species within short distances
of each other. This is a far more varied forest than at the upper
edge of the timber zone or down on the monotonous plains. It
has a higher intrinsic value than any other. That part of it be-
tween the Pongo and Yavero (1,200 to 4,000 feet) is very beauti-
ful, with little undergrowth except a light ground-cover of ferns.
The trees are from 40 to 100 feet in height with an average
diameter of about 15 inches. It would yield from 3,000 to 5,000
board feet per acre exclusive of the palms. There are very few
vines suspended from the forest crown and the trunks run clear
from 30 to GO feet above the ground. Were there plenty of labor
and a good transportation line, these stands would have high eco-
nomic value. Among the most noteworthy trees are the soft white
cedar, strong and liglit; the nmarillo and the sumbayllo, very dura-
ble in water; the black nogal, and the black balsam, straight and
easy to work; the heavy yunquero, which turns pink when dry;
the chunta or black palm, so hard and straight and easy to split

Fig. 94.

Fig. 95.

Fig. 94 — Cloud belt at 11,000 feet in the Apurimac Canyon near Incahuasi. For a
regional diagram and a climatic cross-section see Figs. 32 and 33.

Fig. 95 — The tropical forest near Pabellon on the slopes of the Urubamba Valley.
Elevation 3,000 feet (915 m.).

CLIMATOLOGY OF THE PERUVIAN ANDES 151

that wooden nails are made from it; and the rarer sandy matico,
highly prized for dug-out canoes. Also from the chunta palm, hol-
low except for a few central fibers, easily removed, pipes are made
to convey water. The cocobolo has a rich brown color and a
glossy surface and is very rare, hence is much sought after for
use in furniture making. Most of these woods take a brilliant
polish and exhibit a richness and depth of color and a beauty of
grain that are rare among our northern woods.

The plains forest northeast of the mountains is in the zone of
moderate rainfall where there is one long dry season and one
long wet season. When it is dry the daytime temperatures rise
rapidly to such high levels that the relative humidity of the air
falls below 50 per cent (Fig. 110). The effect on the vegetation is
so marked that many plants pass into a distinctly wilted condi-
tion. On clear days the rapid fall in the relative humidity is
astonishing. By contrast the air on the mountain border heats
more slowly and has a higher relative humidity, because clouds
form almost constantly in the ascending air currents and reflect
and absorb a large part of the heat of the sun's rays. It is strik-
ing to find large tracts of cane and bamboo on the sand bars and
on wet shady hillslopes in the slope belt, and to pass out of them
in going to the plains with which w^e generally associate a swamp
vegetation. They exist on the plains, but only in favored, that is
to say wet, spots. Larger and more typical tracts grow^ farther
north where the heavier rains of the Amazon basin fall.

The floods of the wet tropical season also have a restricting in-
fluence upon the tropical forest. They deliver such vast quantities
of water to the low-gradient lowland streams that the plains
rivers double, even treble, their width and huge pools and even
temporary lakes form in the shallow depressions back of the
natural levees. Of trees in the flooded areas there are only those
few species that can grow standing in water several months each
year. There are also cane and bamboo, ferns in unlimited num-
bers, and a dense growth of jungle. These are the haunts of the
peccary, the red forest deer, and the jungle cat. Except along the
narrow and tortuous animal trails the country is quite impassa-

152 THE ANDES OF SOUTHERN PERU

ble. Thus for the sturdiest and most useful forest growth the
one-wet-one-dry season zone of the plains has alternately too
much and too little water. The rubber tree is most tolerant toward
these conditions. Some of the best stands of rubber trees in Ama-
zonia are in the southwestern part of the basin of eastern Peru
and Bolivia, where there is the most typical development of the
habitat marked by the seasonal alternation of floods and high
temperatures.

When tropical agriculture is extended to the plains the long
dry season will be found greatly to favor it. The southwest-
ern quadrant of the Amazon basin, above referred to, is the
best agricultural area within it . The northern limits of the
tract are only a little beyond the Pongo. Thence northward the
climate becomes wetter. Indeed the best tracts of all extend from
Bolivia only a little way into southeastern Peru, and are coinci-
dent with the patchy grasslands that are there interspersed w^ith
belts of woodland and forest. Sugar-cane is favored by a climate
that permits rapid growth with a heavy rainfall and a dry season
is required for quality and for the harvest. Rice and a multitude
of vegetable crops are also well suited to this type of climate.
Even corn can be grown in large quantities.

At the present time tropical agriculture is almost wholly con-
fined to the mountain valleys. The reasons are not wholly cli-
matic, as the above enumeration of the advantages of the plains
suggests. The consuming centers are on the plateau toward the
west and limitation to mule pack transport always makes distance
in a rough country a very serious problem. The valleys combine
witli the advantage of a short haul a climate astonishingly like the
one just described. Tii fact it is even more extreme in its seasonal
contrasts. The explaii.illoii is dependent upon precisely the same
])riiicil)Ics we have liillicrlo cinjjloycd. 'I'lic front range of the
Andes and iho. course of tlic nnibai)il)a I'liii ])ai-a11('l for some dis-
tance. Furtiicr, Dk' front range is in many places soni(>what
higher lliaii the inonnlaiii spurs and knobs directly behind it.
Even when these relations are reversed the front range still acts
as a barrier to the rains for all llic deep valleys behind it whose

CLIMATOLOGY OF THE PERUVIAN ANDES 153

courses are not directly toward the plains. Thus, one of the
largest valleys in Peru, the Urubamba, drops to 3,400 feet at
Santa Ana and to 2,000 feet at Rosalina, well within the eastern
scarp of the Andes. The mountains immediately about it are from
6,000 to 10,000 feet high. The result is a deep semi-arid pocket
with only a patchy forest (Fig. 54, p. 79).=* In places the degree
of seclusion from the wind is so great that the scrub, cacti, and
irrigation remind one strongly of the desert on the border
of an oasis, only here the transition is toward forests instead
of barren wastes. The dense forest, or montaha, grows in the
zone of clouds and maximum precipitation between 4,000 and
10,000 feet. At the lower limit it descends a thousand feet
farther on shady slopes than it does on sunny slopes. The
continuous forest is so closely restricted to the cloud belt that
in Fig. 99 the two limits may be seen in one photograph. All
these sharply defined limits and contrasts are due to the fact
that the broad valley, discharging through a narrow and remote
gorge, is really to leeward of all the mountains around it. It
is like a real desert basin except in a lesser degree of exclusion
from the rains. If it were narrow and small the rains formed on
the surrounding heights w^ould be carried over into it. Rain on
the hills and sunshine in the valley is actually the day-by-day
weather of the dry season. In the wet season the sky is overcast,
the rains are general, though lighter in the valley pocket, and
plants there have then their season of most rapid growth. The
dry season brings plants to maturity and is the time of harvest.
Hence sugar and cacao plantations on a large scale, hence a
varied life in a restricted area, hence a distinct geographic prov-
ince unique in South America.

INTER-ANDEAN VALLEY CLIMATES

Not all the deep Andean valleys lie on or near the eastern
border. Some, like the Apurimac and the Marafion, extend well

°A dry pocket in the Huallaga basin between 6° and 7° S. is described by Spruce
(Notes of a Botanist on the Amazon and Andes, 2 vols., London, IDOS). Tarapoto at
an elevation of 1,500 feet above sea level, encircled by hills rising 2,000 to 3,000 feet
higher, rarely experiences hea\'y rain though rain falls frequently on the hills.

154 THE ANDES OF SOUTHERN PERU

into the interior of the Cordillera. Besides these deep remote val-
leys with their distinct climatic belts are basins, most of them with
outlets to the sea — broad structural depressions occurring in
some cases along large and in others along small drainage lines.
The Cuzco basin at 11,000 feet and the Abancay basin at 6,000 to
8,000 feet are typical. Both have abrupt borders, narrow outlets,
large bordering alluvial fans, and fertile irrigable soil. Their dif-
ference of elevation occurs at a critical level. Corn will ripen in
the Cuzco basin, but cane will not. Barley, wheat, and potatoes
are the staple crops in the one; sugar-cane, alfalfa, and fruit in
the other. Since both are bordered by high pastures and by min-
eralized rocks, the deeper Abancay basin is more varied. If it
were not so difficult to get its products to market by reason of its
inaccessibility, the Abancay basin would be the more important.
In both areas there is less rainfall on the basin floor than on the
surrounding hills and mountains, and irrigation is practised, but
the deeper drier basin is the more dependent upon it. Many small
high basins are only within the limits of potato cultivation. They
also receive proportionately more rain. Hence irrigation is un-
necessary. According as the various basins take in one or another
of the different product levels (Fig. 35) their life is meager and
unimportant or rich and interesting.

The deep-valley type of climate has the basin factors more
strongly developed. Below the Canyon of Choqquequirau, a topo-
graphic feature comparable with the Canyon of Torontoy, the
Apurimac descends to 3,000 feet, broadens to several miles, and
has large alluvial fans built into it. Its floor is really arid, with
naked gravel and rock, cacti stands, and gnarled shrubs as the
chief elements of the landscape. Moreover the lower part of the
valley is the steeper. A former erosion level is indicated in Fig.
125. When it was in existence the slopes were more moderate than
now and the valley broad and open. Thereupon came uplift and
the incision of the stream to its present level. Asa result, a steep
canyon was cut in tlie floor of a mature valley. Hence the slopes
are in a relation unlike that of most of the slopes in our most
familiar landscapes. The gentle slopes arc above, the steep be-

r2 o C ^

^ — S 1

■^ I <" 2 »

-= ^ H

I 5 g ^

7 — ^5-0

'5'1 C - ^

^' -t ii ^ -2

■I ■ • :z; ^

-=H ;:: ^ o

«*H (-^ ^ TO

1^-1

«3

^.^

;-»

-kJ

■p

"^ tc

o 2 S •"

O K «

-7. O u — .

■^ >:

rS ^

? ^ ■^ 1 2

S O -i
£ S o

''I 13 3d

-3

CL,

■i

o <^

•^

e<S

-t->
o

"to

s
"-5

csi

"ce

e4-H

Cl,

■^

!:3

i-,

s s ^

::: 1^ 33

° !^

■"

.ti

rjT

-1^

■/!

•+J

<«-<

S-.

!-i

.^^

Ol
O

(^ .

•S -^ s

X a !».«+»

■~ o

'f^

«3

"rt

«-i

■/.'

-g

P-

*-'

■p

hl^

r'i

'fj

■M

»*H

CLIMATOLOGY OF THE PERUVIAN ANDES 155

low. The break between the two, a topographic unconformity,
may be distinctly traced.

Combined with these topographic features are certain climatic
features of equal precision. Between 7,000 and 13,000 feet is a
zone of clouds oftentimes marked out as distinctly as the belt of
fog on the Peruvian coast." Rarely does it extend across the val-
ley. Generally it hangs as a white belt on the opposite walls.
When the up-valley winds of day begin to blow it drifts up-valley,
oftentimes to be dissolved as it strikes the warmer slopes of the
upper valley, just as its settling under surface is constantly being
dissolved in the warm dry air of the valley floor. Where the pre-
cipitation is heaviest there is a belt of woodland — dark, twisted
trees, moss-draped, wet — a Druid forest. Below and above the/
woodland are grassy slopes. At Incahuasi a spur runs out and
down until at last it terminates between two deep canyons. No
ordinary wells could be successful. The ground water must be
a thousand feet down, so a canal, a tiny thing only a few inches
wide and deep, has been cut away up to a woodland stream.
Thence the water is carried down by a contour-like course out of
the woodland into the pasture, and so down to the narrow part of
the spur where there is pasture but no springs or streams.

Corn fields surround the few scattered habitations that have
been built just above the break or shoulder on the valley wall
where the woodland terminates, and there are fine grazing lands.
The trails follow the upper slopes whose gentler contours permit
a certain liberty of movement. Then the way plunges downward
over a staircase trail, over steep boulder-strewn slopes to the arid
floor of a tributary where nature has built a graded route. And
so to the still more arid floor of the main valley, where the ample
and moderate slopes of the alluvial fans with their mountain
streams permit plantation agriculture again to come in.

To these three climates, the western border type, the eastern

' Speaking of C6mas situated at the headwaters of a source of the Perene amidst
a multitude of quebradas Raimondi (op. cit., p. 109) says it "might properly be called
the town of the clouds, for there is not a day during the year, at any rate towards
the evening, when the town is not enveloped in a mist sufficient to hide everything
from view."

156 THE ANDES OF SOUTHERN PERU

border type, and the inter-Andean type, we have given chief at-
tention because they have the most important human relations.
The statistical records of the expedition as sho\vn in the curves
and the discussion that accompanies them give attention to those
climatic features that are of theoretical rather than practical inter-
est, and are largely concerned with the conventional expression
of the facts of weather and climate. They are therefore com-
bined in the following chapter which is devoted chiefly to a tech-
nical discussion of the meteorology as distinguished from the
climatology of the Peruvian Andes.

CHAPTER X
METEOROLOGICAL RECORDS FROM THE PERUVIAN ANDES

Introduction

The data in this chapter, on the weather and climate of the
Peruvian Andes, were gathered under the usual difficulties that ac-
company the collection of records at camps scarcely ever pitched
at the same elevation or with the same exposure two days in suc-
cession. Some of them, and I may add, the best, were contributed
by volunteer observers at fixed stations. The observations are
not confined to the field of the Yale Peruvian Expedition of
1911, but include also observations from Professor Hiram Bing-
ham's Expeditions of 1912 and 1914-15, together with data from
the Yale South American Expedition of 1907. In addition I
have used observations supplied by the Morococha Mining Com-
pany through J. P. Little. Some hitherto unpublished observa-
tions from Cochabamba, Bolivia, gathered by Herr Kriiger at con-
siderable expense of money for instruments and of time from a
large business, are also included, and he deserves the more credit
for his generous gift of these data since they were collected for
scientific purposes only and not in connection with enterprises in
which they might be of pecuniary value. My only excuse to Herr
Kriiger for this long delay in publication (they were put into my
hands in 1907) is that I have wanted to publish his data in a digni-
fied form and also to use them for comparison with the data of
other climatic provinces.

A further word to the reader seems necessary before he ex-
amines the following curves and tables. It would be somewhat
audacious to assume that these short-term records have far-reach-
ing importance. Much of their value lies in their organization
with respect to the data already published on the climate of Peru.
But since this would require a delay of several years in their pub-
lication it seems better to present them now in their simplest
form. After all, the professional climatologist, to whom they are

157

158

THE ANDES OF SOUTHERN PERU

chiefly of interest, scarcely needs to have such organization sup-
plied to him. Then, too, ^ve hope that there will become available
in the next ten or fifteen years a vastly larger body of climato-
logical facts from this region. When these have been collected
we may look forward to a volume or a series of volumes on the
** Climate of Peru," with full statistical tables and a complete dis-
cussion of them. That would seem to be the best time for the re-
production of the detailed statistics now on hand. It is only nec-
essary that there shall be sufficient analysis of the data from time
to time to give a general idea of their character and to indicate
in what way the scope of the observations might profitably be ex-
tended. I have, therefore, taken from the available facts only
such as seem to me of the most importance because of their un-
usual character or their special relations to the boundaries of
plant provinces or of the so-called ''natural regions" of
geography.

Machu Picchu^
The following observations are of special interest in that they
illustrate the weather during the southern winter and spring at
the famous ruins of Machu Picchu in the Canyon of Torontoy.
The elevation is 8,500 feet. The period they cover is too short to
give more than a hint of the climate or of the weather for the
year. It extends from August 20, 1912, to November 6, 1912 (79
days).

ANALYTICAL TABLE OF WIND DIRECTIONS, MACHU PICCHU, 1912

Niiinber of ObservationB

Direction of wind

AuR. 20
7 a. m.

1 p. m.

Sept. 80
7 p. m.

Oct. 1
7 n.'m.

1 p. ni.

Nov.
7 p. m.

4
G
8

10
1

2
3

14
2
1
1
1
3
G
2

4
2

12
4
5

G
2
1

4
1
3

N W

s w

s I-:

N E

CALM

* Observer: E. C. Erdis of the 1912 and 1014-15 Expeditions.

METEOROLOGICAL RECORDS

159

Direction of wind

N. -

CALM

Percentages of Total ObeervationB '

Aug. 20 —

7 a. m. 1 p. m.

Sept. 30
7 p. m.

15.6
28.1

12.5

18.8
25.0

8.0

40.0

4.0

8.0
12.0
28.0

14.2
40.0
5.7
2.8
2.8
2.8
8.6
17.1
5.7

Oct. 1

—

Nov. 6

7 a. m.

1 p. m.

7 p. m.

6.7
13.3

35.3

30.7

6.7

11.8

11.1

3.3

5.9

16.7
5.5

40.0
13.3
16.7

23.5

5.9

17.6

11.1
8.3
8.3

The higli percentage of northwest winds during afternoon
hours is due to the up-valley movement of the air common to almost
all mountain borders. The air over a mountain slope is heated
more than the free air at the same elevation over the plains (or

N , N _ N

7 a.m

1 p.m.

7 p.m

Fig. 100 — Wind roses for Macliu ricehii, August 20 to November 6, 1912.

lower valley) ; hence a barometric gradient towards the mountain
becomes established. At Machu Picchu the Canyon of Torontoy
trends northwest, making there a sharp turn from an equally
sharp northeast bend directly upstream. The easterly components
are unrelated to the topography. They represent the trades. If
a wind rose were made for still earlier morning hours these winds
would be more faithfully represented. That an easterly and
northeasterly rather than a southeasterly direction should be as-
sumed by the trades is not difficult to believe when we consider
the trend of the Cordillera — southeast to northwest. The observa-

Percentages given because the number of observations varies.

160

THE ANDES OF SOUTHERN PERU

tions from here down to the plains all show that there is a distinct
change in wind direction in sjTnpathy with the larger features of
the topography, especially the deep valleys and canyons, the trades
coming in from the northeast.

CLOUDINESS

It will be seen that the sky was overcast or a fog lay in the
valley 53 per cent of the time at early morning hours. Even at
noon the sky was at no time clear, and it was more than 50 per
cent clear only 18 per cent of the time. Yet this is the so-called
**dry" season of the valleys of the eastern Andes. The rainfall
record is in close sympathy. In the 79 days ' observations rain is
recorded on 50 days with a greater proportion from mid-Septem-
ber to the end of the period (November 6), a distinct transition
toward the wet period that extends from December to May. The
approximate distribution of the rains by hours of observation
(7 A. M., 1 p. M., 7 p. M.) was in the ratio 4:3:6. Also the greatest
number of heavy showers as well as the greatest number of
showers took place in the evening. The rainfall was apparently
/Unrelated to wind direction in the immediate locality, though un-
doubtedly associated with the regional movement of the moist
[plains air toward the mountains. All these facts regarding
clouds and rain plainly show the location of the place in the belt
of maximum precipitation. There is, therefore, a heavy cover of
vegetation. While the situation is admirable for defence, the
murky skies and frequent fogs somewhat offset its topographic
surroundings as a lookout.

ANALYTICAL TABLE OF THE STATE OF THE SKY, MACIIU PICCllU, 1912

Fo^'^TJ'

Overrnst

r,0-\00% cloudy
0-50% cloudy . .
Clear

MornlDK

Anjj.'
Sept.

3.0
12.0

4.0

n.o

3.0

Oct..
Nov.

14.0

3.0

10.0

Totttl

Days

17.0 28.4
15.0 25.0
14.0 23.3
4.0|10.0!1G.7
1.0 4.0 1 6.6

Noon

Aug.
Sept.

1.0
0.0

n.o

5.0
0.0

Oct..
Nov.

8.0

7.0
2.0
0.0

Total

Day^

1.0

14.0

in.o

7.0
0.0

2.G

30.8

42.2

18.4

0.0

Kvcnin^

Aug.
Sept.

1.0

13.0

8.0

9.0
3.0

Oct.-
Nov.

2.0

11.0

15.0

4.0

3.0

Total

Hay*

3.0
24.0
2.3.0
13.0

6.0

4.3
34.8
33.3

18.8
8.8

METEOROLOGICAL RECORDS

161

Santa Lucia ^
Santa Lucia is a mining center in the province of Puno (16°
S.), at the head of a valley here running northeast towards Lake
Titicaca. Its elevation, 15^500 feet above sea level, confers on it
unusual interest as a meteorological station. A thermograph has
been installed which enables a closer study of the temperature to be
made than in the case of the other stations. It is unfortunate, how-
ever, that the observations upon clouds, wind directions, etc., should
not have been taken at regular hours. The time ranges from 8.30
to 11.30 for morning hours and from 2.30 to 5.30 for afternoon.
The observations cover portions of the years 1913 and 1914.

TEMPERATURE

Perhaps the most striking features of the weather of Santa
Lucia are the highly regular changes of temperature from night
to day or the uniformly great diurnal range and the small dif-
ferences of tempera-ture from day to day or the low diurnal
variability. For the whole period of nearly a year the diurnal
variability never exceeds 9.5° F. (5.3° C.) and for days at a time
it does not exceed 2-3° F. (1.1°-1.7° C). The most frequent varia-
tion, occurring on 71 per cent of the total number of days, is from
0-3° F., and the mean for the year gives the low variability of
1.9° F. (1.06^ C). These facts, illustrative of a type of w^eather
comparable in uniformity with low stations on the Amazon plains,
are shown in the table following as well as in the accompanying
curves.

FREQUENCY OF THE DIURNAL VARIABILITY, SANTA LUCIA, 1913-1-4

Degrees F.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

Jan.

Feb.

March

Total No.
of days

—

0-1

1-2

2-3

3-4

4-5

—

Over 5

—

Days pel

321

month

'Observer: Senor Valdivia. For location of Santa Lucia see Fiff. 66.

162 THE ANDES OF SOUTHERN PERU

If T\'e take the means of the diurnal variations by months we
have a still more striking curve showing how little change there
is between successive days. June and December are marked by
humps in the curve. They are the months of extreme weather
when for several weeks the temperatures drop to their lowest or
climb to their highest levels. Moreover, there is at these lofty
stations no pronounced lag of the maximum and minimum tem-
peratures for the year behind the times of greatest and least heat-
ing such as we have at lower levels in the temperate zone. Thus
we have the highest temperature for the year on December 2,
lOA" F. (21.3° C), the lowest on June 3, 0.2° F. (—17.7° C). The
daily maxima and minima have the same characteristic. Radiation
is active in the thin air of high stations and there is a very
direct relation between the times of greatest heat received and
greatest heat contained. The process is seen at its best immedi-
ately after the sun is obscured by clouds. In five minutes I have
obser^^ed the temperature drop 20° F. (11.1° C.) at 16,000 feet
(4,877 m.) ; and a drop of 10' F. (5.6° C.) is common anywhere
above 14,000 feet (4,267 m.). In the curves of daily maximum and
minimum temperatures we have clearly brought out the uniform-
ity with which the maxima of high-level stations rise to a mean
level during the winter months' (May- August). Only at long in-
tervals is there a short series of cloudy days when the maximum
is 10^-12° F. (5.6°-6.7' C.) below the normal and the miiiiinum
stands at abnormally liigli levels. Since clouds form at night
in quite variable amounts — in contrast to the nearly cloud-
less days— there is a far greater variability among the minimum
temperatures. Indeed the variability of the winter minima
is greater than that of the summer minima, for at the latter
season the nightly cloud cover imposes much more stable atmos-
pheric temperatures. The summer maxima have a greater
degree of variability. Several clear days in succession allow
the temperature to rise from r)°-10" F. (2.R°-r).6° C.) above
the wiutor maxima. P»ut such extremes are rather strictly
confined to the height of the summer season— December and
January. For the rest of the summer the maxima rise only

METEOROLOGICAL RECORDS 163

a few degrees above those of the winter. This feature of the
climate combines with a December maximum of rainfall to limit
the period of most rapid plant growth to two months. Bar-
ley sown in late November could scarcely mature by the end of
January, even if growing on the Argentine plains and much less
at an elevation which carries the night temperatures below freez-
ing at least once a week and where the mean temperature hovers
about 47° F. (8.3° C). The proper conditions for barley growing
are not encountered above 13,000 to 13,500 feet and the farmer
cannot be certain that it will ripen above 12,500 feet in the lati-
tude of Santa Lucia.

The curve of mean monthly temperatures expresses a fact of
great importance in the plant growth at high situations in the
Andes — the sharp break between the winter and summer seasons.
There are no real spring and autumn seasons. This is especially
well shown in the curve for non-periodic mean monthly range of
temperature for the month of October. During the half of the
year that the sun is in the southern hemisphere the sun's noon-
day rays strike Santa Lucia at an angle that varies between 0° and
16° from the vertical. The days and nights are of almost equal
length and though there is rapid radiation at night there is also
rapid insolation by day. When the sun is in the northern hemi-
sphere the days are shortened from one to two hours and the angle
of insolation decreased, whence the total amount of heat received
is so diminished that the mean monthly temperature lies only a
little above freezing point. In winter the quiet pools beside the
springs freeze over long before dark as the hill shadows grow
down into the high-level valleys, and by morning ice also covers
the brooks and marshes. Yet the sun and wind-cured ichu grass
lives here, pale green in summer, straw-yellow in winter. The
tola bush also grows rather abundantly. But we are almost
at the upper limit of the finer grasses and a few hundred feet
higher carries one into the realm of the snowline vegetation,
mosses and lichens and a few sturdy flowering plants.

For convenience in future comparative studies the absolute
extremes are arranged in the following table:

164 THE ANDES OF SOUTHERN PERU

ABSOLUTE MONTHLY EXTREMES, SANTA LUCIA., 1913-14

Date

Highest

Lowest

Date

^£ay* (12)

62° F.

9°F.

May (25, 26)

June (4 days)

60° F.

0.2° F.

June (3)

July (4 days, 31)

60° F.

5°F.

July (8)

Aug. (8, 26)

62° F.

4°F.

Aug. (4, 5)

Sept. (several days)

62° F.

7°F.

Sept. (4 days)

Oct. (24)

63° F.

10° F.

Oct. (12, 13)

Nov. (11) '

63° F.

24.0° F.

Nov. (29)

Dec. (2)

70.4° F.

22.2° F.

Dec. (14)

Jan. (19)

69.5° F.

26.5° F.

Jan. (3, 15)

Feb. (16,1S)

63.2° F.

30.5° F.

Feb. (23)

March (8)

68.4° F.

28.5° F.

March (6)

RAINFALL

The rainfall record for Santa Lucia is for the year beginning
November, 1913. For this period the precipitation amounts to
24.9 inches of which over 85 per cent fell in the rainy season from
November to March. Most of the rain fell during the violent after-
noon tempests that characterize the summer of these high alti-
tudes.

The rainfall of Santa Lucia for this first year of record ap-
proximates closely to the yearly mean of 23.8 inches for the sta-
tion of Caylloma in the adjacent province of that name. Caylloma
is the center of a mining district essentially similar to Santa
Lucia though the elevation of its meteorological station, 14,196
feet (4,330 m.), is lower. It is one of the few Peruvian stations
for which a comparatively long series of records is available. The
Boletin de la Sociedad Geogrdfica de Lima " contains a resume of
rainfall and temperature for seven years, 1896-7 to 1902-3. Later
data may be foujid in snl)sequent volumes of the same publication
but they have not been summarized or in any way i)repared for
analysis and they contain several typ()gra])hical errors. A graphic
representation of the iiioiinily rainfall for the earlier ])('ri()d is
here reproduced from llic Unlet m de minas del Peru J Tlie

* Obscrvntions bognn on May 12.

' Tor tlio first linlf of the month only; no record for the spcond lialf.

• I'.olotfn do ha Socirdad r.fogrflfifa d<- Lima, Voh LI, pp. •17.'t-4Hn, Lima, DO."?.

' Bolftfn del f'ucrpo do Ingt-nicroB do Minas del IVrrt, No. ?,\, Lima, 1905, also
reproduced in No. 45, 1906.

METEOROLOGICAL RECORDS

165

IN.

--500

--200

MM. IN.
12-

■250

■150

= -50

2o0

iLq Q_

MM,

-200

= -100

n. d. j. e. m. a. m. j. j. a. s. o.
Fig. 102.

J. F. M. A. M. J. J. A. S. O. N. D.

Fig. 103A.

IN.

30-

20-

10-

CAYLLOMA

SANTA
LUCIA

--«X)

MM.

-1000

600

= -400

-200

■^ lo o t^ 00 a> o

tDt-00^0^(M ^

o^ a> <ji .J-* S o o r^

CO CO CO — <yi a> Oi uQ

s f g

O Oi o

C3> O gH

Fig. 103B.

Fig. 102 — Montlily rainfall of Santa Lucia for the j-ear Xovember, 1913,
to October, 1914. No rain fell in July and August.

Fig. 103A — Maximum, mean and minimum monthly rainfall of Caylloma
for the period 1896-7 to 1902-3. July was absolutely rainless. Caylloma ia
situated immediately east of the crest of the Maritime Cordillera in a position
similar to that of Santa Lucia (see Fig. GG).

Fie. 103B — Annual rainfall of Caylloma for the periods 1896-7 to 1902-3;
1903-4 to 1910-11 and for 1915-6 (incomplete: May and Jime, months of low
rainfall, are missing). Means for the respective seven and eight year periods are
shown and the rainfall of Santa Lucia for the single observation year is inserted
for comparison.

166

THE ANDES OF SOUTHERN PERU

amount of precipitation fluctuates considerably from year to year.
For the earlier period, with a mean of 23.8 inches the minimum
(1896-7) was 8 inches and the maximum (1898-9) 36 inches. For
the later period, 1903-4 to 1910-11, with a mean of 29.5 inches the
minimum (1904-5) was 17.5 inches and the maximum (1906-7) was
43 inches.

RAINFALL, SANTA LUCIA, NOV. 1913 TO OCT. 1914

No of
fine clays

No. of
rainy days

AJax. for
single day

Total rainfall
in inclics

November

21
15
14
17
20
13
23

7
10

1.150
.700
.010
.910
1.102
0.31
0.35
0.05
0.00
0.00
0.05
0.14

4.264 '

December

16
17

9
11
17

8
27
31

6.439

January

3.313

February

2.975

ilarch

4.381

April

0.92

Mav

1.63

June

0.07

July

0.00

August

September

October

31
23

0.00
0.35
0.56

Total

24.902

WIND

xVn analysis of the wind at Santa Lucia shows an excess of
north and south winds over those of all other directions. The
wind-rose for the entire period of observation (Fig. 104) clearly
expresses this fact. AVhen tills element is removed wo observe a
strongly seasonal distribution of the wind. The winter is the time
of north and south winds. In summer the winds are chiefly from
the northeast or the southwest. Among single months, August
and Fcljruary show this fact clearly as well as the less decisive
character of the summer (February) wind.

The mean wind velocity for the month of February was 540
meters pf-r minute for the morning and 470 meters per minute for
the afternoon. The higher morning rate, an unusual feature of

' Tlie roronl is copied litrrally witlioiit rognrd to (lie iiliHiirdity of tlio second
nnd third dccimnl places.

METEOROLOGICAL RECORDS

167

JUKE. 1913

Fig. 104 — Monthly wind roses for Santa Lucia, June, 1913, to July, 1914, and
composite rose for the whole period of observation.

168

THE ANDES OF SOUTHERN PERU

the weather of high stations, or indeed of wind-phenomena in gen-
eral, is due, however, to exceptional changes in wind strength on
two days of the month, the 16th and 25th, when the velocity de-
creased from a little less than a thousand meters per minute in
the morning to 4 and 152 meters respectively in the afternoon.
More typical is the March record for 191-4 at Santa Lucia, when
the wind was always stronger in the afternoon than in the morn-
ing, their ratios being 550 to 510.

/ CLOUD

/ The greater strength of the afternoon wind would lead us to
Suppose that the cloudiness, which in the trade-wind belt, is to so
great an extent dependent on the wind, is greatest in the after-
noon. The diagrams bring out this fact. Rarely is the sky quite
clear after the noon hour. Still more striking is the contrast be-
ween the morning and afternoon if we combine the two densest
shadings of the figures. Light, high-lying cirrus clouds are most
characteristic of early morning hours. They produce some very
striking sky effects just before sunrise as they catch the sun's rays
aloft. An hour or two after sunrise they disappear and small
cumulus clouds begin to form. These grow rapidly as the winds
begin and by afternoon become bulky and numerous. In the wet
season they grow into the nimbus and stratus types that precede
a sudden downpour of water or a furious hailstorm. This is best
seen from the base of a mountain range looking towards the crest,
where the cloud- and rain-making processes of this type are most
active.

CLOUD ANALYSIS, SANTA LUCIA

Type of cloud

Nov.
a. m. p.

Dec.
B. m. p. m.

Jan.
a. m. p

V
a. in.

I'l).
p. ni.

March
a. m. p. ni.

Total
a. tn. p. m.

\
3
2

4
4
(i

15 2

7 11

4 7

3 10

— 1

2 —

6 3

17 10

5 13

— 3

1 2

2 .

41 12

— —

r!irrr>-PiimiiliiH

37 38

37 46

14 36

Stratus

2 4

Nimbus

— —

Clear

6 1

METEOROLOGICAL RECORDS

169

UNUSUAL WEATHER PHENOMENA, SANTA LUCIA, 1913-14

The following abstracts are selected because they give some
important features of the weather not included in the preceding
tables and graphs. Of special interest are the strong contrasts

a..m. Jan. p.m.

a.m. May p.m.

"■<<i4^g^i'^

Clear

!>-- 1 0-2.6

Scale of Cloudiness
2.5-7.5

7.5-10

Completely
Overcast

Fig. 105 — Monthly cloudiness of Santa Lucia from January to July, 1914. Mean
cloudiness for the whole period is also shoMTi.

between the comparatively high temperatures of midday and the
sudden ''tempests " accompanied by rain or hail that follow the
strong convectional movements dependent upon rapid and unequal
heating. The furious wdnds drive the particles of hail like shot.
It is sometimes impossible to face them and the pack train must

170 THE ANDES OF SOUTHERN PERU

be halted until the storm has passed. Frequently they leave the
ground white with hailstones. We encountered one after another
of these "tempestades" on the divide between Lambrama and
Antabamba in 1911. They are among the most impetuous little
storms I have ever experienced. The longest of them raged on
the divide from two-o'clock until dark, though in the valleys the
sun was shining. Fortunately, in this latitude they do not turn
into heavy snowstorms as in the Cordillera of northwestern
Argentina, where the passes are now and then blocked for weeks at
a time and loss of human life is no infrequent occurrence.® They
do, however, drive the shepherds down from the highest slopes to
the mid-valley pastures and make travel uncomfortable if not
unsafe.

ABSTRACT FROM DAILY WEATHER OBSERVATIONS, SANTA LUCIA, 1913-14

NOVEMBER

" Tempest " recorded 11 times, distant thunder and lightning 9 times.
Unusual weather records: "clear sky, scorching sun, good weather" (Nov. 29);
"morning sky without a single cloud, weather agreeable" (Nov. 30).

DECEMBER

Clear morning sky 6 times. Starry night or part of night 7 times.

Beginning of rain and strong wind frequently observed at 5-G p. M.

" Tempest " mentioned 19 times — 5 times at midnight, 8 times at 5-G p. M.

JANUARY

Clear morning sky 5 times. Starry night 3 times.

Rain, actual or threatening, characteristic of afternoons.

" Tempest," generally about 5-6 p. m., 7 times.

Sun described 4 times as scorching and, when witiioul wind, heat as stifling.

Weather once " agreeable."

FEBRUARY

Constant cloud changes, frequent afternoon or evening rains.
"Tempest," gonfrally 4 r. Ai. and lalcr, ^^^■ times.

• In tlic EnHtcrn Cordillera, however, snowstorms may he more serious. Prior to
tho conHtruction of Uie Uru1)aml)a Valley Road by tlio Peruvian government the three
main routes to the Santa Ana portion of the valley proeecded via the passes of Saleantiiy,
Pnntiealla, and Yanahuara respectively. Frequently all are completely snow-blocked
and fatalities are by no means unknown. In ISflt for iiist-inec nine persons succumbed
on the Yanahuara pass (Raimondi, op. cit., p. 109).

METEOROLOGICAL RECORDS 171

MARCH

Twice clear morning skies, once starry night.
Scorching sun and stifling heat on one occasion.

" Tempest," generally in late afternoon and accompanied by hail, 19 times.
Observed 3 or 4 times a strong "land breeze" (terral) of short duration (15-20
mins.) and at midnight.

MOROCOCHA

Morococha, in the Department of Ancaclis, Peru, lies in 76° 11'
west longitude and 11° 45' south latitude and immediately east of
the crest line of the Maritime Cordillera. It is 14,300 feet above
sea level, and is surrounded by mountains that extend from 1,000
to 3,000 feet higher. The weather records are of special interest
in comparison with those of Santa Lucia. Topographically the
situations of the two stations are closely similar hence we may
look for climatic differences dependent on the latitudinal differ-
ence. This is shown in the heavier rainfall of Morococha, 4°
nearer the equatorial climatic zone. (For location see Fig. 66.)

The meteorological data for 1908-09 were obtained from rec-
ords kept by the Morococha Mining Company for use in a pro-
jected hydro-electric installation. Other data covering the years
1906-11 have appeared in the bulletins of the Sociedad Geogrd-
fica de Lima. These are not complete but they have supplied rain-
fall data for the years 1910-11 ; '' those for 1906 and 1907 have
been obtained from the Boletm de Minas}^

Temperature >.

The most striking facts expressed by the various temperature
curves are the shortness of the true winter season — its restriction
to June and July — and its abrupt beginning and end. This is well /
known to anyone who has lived from April to October or Novem-
ber at high elevations in the Central Andes. Winter comes on
suddenly and with surprising regularity from year to year dur-
ing the last few days of May and early June. In the last week of
July or the first week of August the temperatures make an equally
sudden rise. During 1908 and 1909 the mean temperature reached
the freezing point but once each year — July 24 and July 12 re-

'"Boletln de la Sociedad Geografica de Lima, Vol. 27, 1911; Vol. 28, 1912.
*^ Boletfn del Cuerpo de Iiigenieros de Minas del Peril, No. 65, 1908.

172 THE ANDES OF SOUTHERN PERU

spectively. The absolute minimum for the two years was - 22° C.
July of 1908 and June of 1909 are also the months of smallest
diurnal variability, showing that the winter temperatures are
maintained with great regularity. Like all tropical high-level sta-
tions, Morococha exhibits winter maxima that are very high as
compared with the winter maxima of the temperate zone. In both
June and July of 1908 and 1909 the maximum was maintained for
about a week above 55° F. (12.8= C), and in 1909 above 60° F.
(15.6° C), the mean maximum for the year being only 4.7° F.
higher. For equal periods, however, the maxima fell to levels
about 10° F. below those for the period from December to
May, 1908.

It is noteworthy that the lowest maximum for 1909 was in
October, 44° F. (6.7° C); and that other low maxima but little
above those of June and July occur in almost all the other months
of the year. While 1909 was in this respect an exceptional year,
it nevertheless illustrates a fact that may occur in any month of
any year. Its occurrence is generally associated with cloudiness.
One of the best examples of this is found in the January maximum
curve for 1909, M^here in a few days the maxima fell 12° F. Cloud
records are absent, hence a direct comparison cannot bo made, but
a comparison of the maximum temperature curve with the graphic
representation of mean monthly rainfall, will emphasize this rela-
tion of temperature and cloudiness. February was the wettest
month of both 1908 and 1909. In sympathy with this is the large
and sharp drop from the January level of the maxima — the highest
for the year — to the February level. The mean temperatures are
affected to a less degree because the cloudiness retards night radia-
tion of boat, thus elevating the maxima. Thus in 1908 tlie lowest
minimum for both January and February was 28.4° F. ( — 2° C).
For 1900 the minima for January and February were 27.5° F.
(—2.5° C.) JiTid L'9.:5' V. (—1.5" C.) respectively.

The extent to whicli IiIl-Ii iiiiiiiiii;i may liohl up tlic mean tem-
perature is shown by the fact liiat tlie iiK'nri inontlily tempera-
ture for January, 1908, was lower tlian for P'ebiTiary. Single
instances illustrate this relation equally well. For example, on

CROC

(/TOROC

•lOROC

FIG. 106 A - DIURNAL TEMPERATURE, MOR0(X>CHA. 1908

FIG. 106 D - DIURNAL RANGE OF TEMPERATURE. HOROCOCHA, 1908

i^?Si5^

'-^^m

m^:

fS:

:2^

FIG. 106 E - DIURNAL RANGE OF

MOROCOCHA. ;

;^^^gs§^

^v±

;PM^

i§i-^^:^^lg;

106 G - DIURNAL VARIABILITY OF TEMPERATURE, MOROCOCHA, 1

•^"Vy-vkEI I ITr^TJEkipId;;;;!^?^^^

FIG. 106 H - DIURNAL VARIABILITY OF TEMPERATURE. MOROCOCHA, 1909

n CiEMdNATydjMd^^JI^ y^ckL J-J A?bkJwd^p4=p^CTl^^

x:j 73 .'ZkTqrThd/XH-'lJ. ^L ..

FIG. 106 C - MEAN MONTHLY TEMPERATURE, MOROCOCHA

FIG.

06 F-

MONTHLY MEANS OF DIURNAL R

.E OF TEMPERATURE, MOROCOCHA

p n

J.M,

^•

.> ,M_U^

-.i

- "

1 _-

„;'

■'

■V

— U-^

J/I ists

?«'

1 ,

-4-^

^ 1 1

jri

iBostiaw

1 — 1

METEOROLOGICAL RECORDS

173

March 5th, 1908, there occurred the heaviest rainfall of that year.
The maximum and minimum curves almost touch. The middle of
April and late September, 1909, are other illustrations. The rela-
tionship is so striking that I have put the two curves side by side
and have had them drawn to the same scale.

FKEQUENCY OF THE DIURNAL. VARIABILITY, MOROCOCHA, 1908 AND 1909

1908

Degrees F.

i\r.

Total No.
of days

0-1

1-2

2-3

3-4

4-5

—

Over 5

—

Days per

339

month

1909

Degrees F.

Total
No. of
days

Mean

for 1908
-1909

27.5

0-1

1-2

2-3

3-4

48.5

4-5

—

Over 5

—

34.5

Days per

364

351.5

month

RAINFALL

The annual rainfall of Morococha is as follows :

1906 28 inches ( 712 mm.)

1907 40 " (1,011mm.)

'' 1908 57 " (1,450 mm.)

1909 45 " (1,156 mm.)

1910 47 " (1,195 mm.)

1911 25 " ( 622 mm.)

*" This figure is approximate: some days' records were missing from the first
three months of the year and the total was estimated on a proportional basis.

174

THE ANDES OF SOUTHERN PERU

a
o

O
0>

s
s

r ^ ? ^ <i

' —

II6I
0I6I
6061
S06I
i06I
9061

_ — -g
I

o <» (> + w o

22 2

■^ ^

I-,

g«2

-^ rt

(» <M

O fl

H -S

S ^

n g

^- ei

>> a

'5 -2

S s

•s -^

-i-> rt

.5 §

tH C«

TS «

-=3

Ainr

^ o

G t^

NV-r

iinr

NVT

^.inr

o ^
,c "-I

00 l-H

Nvr

o ^

\inr

''C §

Nvr

\nnr

13 a

P3 =2

^ 1-1

£ ,a
1—1 .^

METEOROLOGICAL RECORDS 175

The mean for the above six years amounts to 40 inches (1,024
mm.). This is a value considerably higher than that for Cayl-
loma or Santa Lucia. The greater rainfall of Morococha is prob-
ably due in part to its more northerly situation. An abnormal
feature of the rainfall of 1908, the rainiest year, is the large
amount that fell in June. Ordinarily June and July, the coldest
months, are nearly or quite rainless. The normal concurrence
of highest temperatures and greatest precipitation is of course
highly favorable to the plant life of these great altitudes. Full
advantage can be taken of the low summer temperatures if the \
growing temperatures are concentrated arid are accompanied by
abundant rains. Since low temperatures mean physiologic dry-
ness, whether or not rains are abundant, the dryness of the winter
months has little effect in restricting the range of Alpine species.

The seasonal distribution of rain helps the plateau people as
well as the plateau plants. The transportation methods are
primitive and the trails mere tracks that follow the natural lines
of topography and drainage. Coca is widely distributed, likewise
corn and barley which grow at higher elevations, and wool must
be carried down to the markets from high-level pastures. In the
season of rains the trails are excessively wet and slippery, the
streams are often in flood and the rains frequent and prolonged.
On the other hand the insignificant showers of the dry or non-
growing season permit the various products to be exchanged
over dry trails.

The activities of the plateau people have had a seasonal expres-
sion from early times. Inca chronology counted the beginning of
the year from the middle of May, that is when the dry season was
well started and it was inaugurated with the festivals of the Sun.
With the exception of June when the people were entirely busied
in the irrigation of their fields, each month had its appropriate
feasts until January, during which month and February and
March no feasts were held. April, the harvest month, marked the
recommencement of ceremonial observances and a revival of social
life.^^ '

" Christoval cle Molina, The Fables and Rites of the Yncas, Hakluyt Soc. Pubis., 1st
Ser., No. 48, 1873.

176 THE ANDES OF SOUTHERN PERU

In Spanish times the ritualistic festivals, incorporated with
fairs, followed the seasonal movement. Todaj" progress in trans-
portation has caused the decadence of many of the fairs but others
still survive. Thus two of the most famous fairs of the last cen-
tury, those of Vilque (province of Puno) and Yunguyo (province
of Chucuito), were held at the end of May and the middle of
August respectively. Copacavana, the famous shrine on the
shores of Titicaca, still has a well-attended August fair and
Huari, in the heart of the Bolivian plateau, has an Easter fair
celebrated throughout the Andes.

COCHABAMBA

Cochabamba, Bolivia, lies 8,000 feet above sea level in a broad
basin in the Eastern Andes. The Cerro de Tunari, on the north-
west, has a snow and ice cover for part of the year. The tropical
forests lie only a single long day's journey to the northeast. Yet
the basin is dry on account of an eastern front range that keeps
out the rain-bearing trade winds. The Rio Grande has here cut
a deep valley by a roundabout course from the mountains to the
plains so that access to the region is over bordering elevations.
The basin is chiefly of structural origin.

The weather records from Cochabamba are very important. I
could obtain none but temperature data and ihcj arc complete for
190G only. Data for 1882-85 were secured by von Boeck " and they
have been quoted by Sievers and Hann. The mean annual tem-
perature for 1906 was 61.9° F. (16.6° C), a figure in close agree-
ment with von Boeck's mean of 60.8° F. (16° C). Tlic inoiilhly
means indicate a level of temperature favorable to ngriculluro.
The basin is in fact the most fertile and highly cultivated area of
its kind in Bolivia. Bananas, as well as many other tropical and
subtroj)ical i)lants, grow in the central plaza. The nights of mid-
winter are uncomfortably cool; mid tlic days of niidsuiiinior are

"Sec M«'t«-orolopiHoho Zcitsclirifi, Vol. T). p. 10.'), IHHH. Also citr.] hy J. Ilium in
Hnnfllnifli rlir C'lininfolo(,no, V(»l. 2, Stiitt^'iirt, 1M!»7 ; W. SicviTH, Si'nl iind Mil ((•hiiiicrikM.
Lfii)zig and Vienna, 1914, p. 334.

1—^

\ n

/ /

V ,

■5

10"

.77

ul.

Dr-

:or

re-

ire

ler
ar-
ms
is-
ag,
of
re-

sly

m-
the
re-
Its

■ —

DEC.

'vJ

-x.^

OF DIURNAL RANGE,

COCHABAMBA

1907

' V

— '~

■5

. 108 A -DIURNAL TEMPERATURE.

-?!5z

:?sk^

^:^=tfe::^aH:2f

's^l

FIG.

08 B

- DIURNAL TEMPERATURE

, COCHABAMBA

, 1907

ao
so

f 1

F.B. ,

lUi

Bli.

<!^,

—

rr-tH-^,vk'

^-^

—•7^

—

=^^^SR^

^-^

-1

_• =

VAv

■V-

'^^

--^

7--

■'

FIG. 103 E - DIURNAL RANGE OF TEMPERATURE,

FIG. 108 D - DIURNAL RANGE OF TEMPERATURE. COCHABAMBA. 1906

FIG. 108 G -DIURNAL VARIABILITY. COCHABAMBA. 1906

Ai AJ^/i^i/v^ \\-^A.Aa

M^^n-W^^A J-\ivL/NA>\J^l

^ I n I MM |°f! , ., .

FIG. 108 C - MEAN MONTHLY TEMPERATURES, COCHABAMBA

AJAyK%J\K^^l^>X^

FIG. 108 H - DIURKAL VARIABILITY, COCHABAMBA. 1907

... *:;ii:

METEOROLOGICAL RECORDS

177

uncomfortably hot but otherwise the temperatures are delightful.
The absolute extremes for 1906 were 81.5° F. (27.5° C.) on Decem-
ber 11, and 39.9° F. (4.4° C.) on July 15 and 16. The (uncor-
rected) readings of von Boeck give a greater range. High minima
rather than high maxima characterize the summer. The curve for
1906 shows the maxima for June and July cut off strikingly by an
abrupt drop of the temperature and indicates a rather close re-
striction of the depth of the season to these two months, wliich are
also those of greatest diurnal range.

The rainfall of about 18 inches is concentrated in the summer
season, 85 per cent falling between November and March. Dur-
ing this time the town is somewhat isolated by swollen streams
and washed out trails : hence here, as on the plateau, there is a dis-
tinct seasonal distribution of the work of planting, harvesting,
moving goods, and even mining, and of the general commerce of
the towns. There is an approach to our winter season in this re-
spect and in respect of a respite from the almost continuously
high temperatures of summer. The daytime temperatures of sum-
mer are however mitigated by the drainage of cool air from the
surrounding highlands. This, indeed, prolongs the period re-
quired for the maturing of plants, but there are no harmful results
because freezing temperatures are not reached, even in winter.

MONTHLY TEMPERATURES, COCHABAMBA, 1906

Month

January .
February .
March . . .
April . . . .

May

June

July

August . . ,
September
October . .
November
December

Mean Min.

55.7
61.2

59.8

55.06

50.9

47.1

44.8

49.9

55.6

56.1

58.1

58.6

Mean Max.

72.25

71.3

72.6

70.8

68.7

65.6

64.9

68.0

73.2

73.4

75.7

73.9

Mean Range

16.65
10.1

12.8

15.74

17.8

18.5

20.1

18.1

17.6

17.3

17.6

15.3

Daily Mean

63.3
65.5
65.5
62.2
59.1
55.6
54.1
58.2
63.7
64.0
66.2
65.8

178

THE ANDES OF SOUTHERN PERU

°^

—

■i-

■>

Sil

) :

§.

/i;

•S

>/;'

^ '^

1 L

-\ <-

^' h

1 P^'-' 1

•A

1 '^

•Tt

■^

'^.

■•-

_jS

>»

i!--

v''

1?. ■

•^''^

^ O

S ;::

/ :

B .,•

—

--^

a 2

•,

>"'

<§

) ]

/;,

"'"

** "

"■v

1 •

'.'

../

;

*•'

•*«,

■:■

■N ^

■i

(

/-.-

V-

:^c

"fc.

(

a '

h"5

c
o

•

(

„

'■

<«

;

(

)

c
"5

■'

!bj

A-

•*

■~

■4<.'

^■'

■o
c

*-■

;;:

-■

a
9

■"

fa'

Of i^;i

°^

T" Tf

:^ - ^

■^' -,*-•-' '^

sr '"1--

I ^

. < 9

. _^__ _ =3

.^<::__ _J

X ^

' -1

"* —

"■-V ^

^ a

-^i o 8

O eS O

1 ^ =^

•—I CS ^ O)

r-( 3

p ^ •= 5

O Q ^ "^

. •- 5 ^

2 rd >, 5)

OT O ^

& >*- o 3

< o « g

0)^04

c3 5 t.

a g .s fa

aj j_ ••> •

I ^ C ??

O ■<-' |>| bo

fa ^

1 X

■^ "^ 2 «

t- >— I CO

2 S gfa^

* '-' .,""•%

(U O 03 ^ rt

C ^ J5 TO

a; ^ o; a

- CS iii O c3

;: o ^ (M M

I- ii -^ & ■"

a rt „ p fo

tr^

'"' .5 > -S

cr fa

.S -^

a> >» CI]

•S o

TJ ^ _.,

£ ^'fa -^

Fig. 114.

/ \

(

Nor

Tial Curv

CLOUDS \

/ 1
1 1
1 1

1 1
1 I

1 1

Dry

Bulb-V
/

—

Wet

Bulb

6£

.m.

)on

.m.

dt.

20°

Fig. 115.

Fig. 114 — Typical afternoon cloud composition at Santa Ana during the dry season.

Fig. 115 — Temperature curve for Abancay drawn from data obtained by hourly
readings on September 27, 1911. Dry bulb readings are shown by a heavy solid
line, wet bulb readings by a dotted line. The heavy broken line shows the normal
curve when the sky is unobscured by cloud. The reduction in temperature with cloud
is very marked.

METEOROLOGICAL RECORDS 179

FREQUENCY OF DIURNAL VARIABILITY AT COCHABAMBA, 1906

Degrees F.

Total No. of
days

0-1

—

1-2

143

2-3

3-4

4-5

—

Over 5

—

A series of curves shows the daily march of temperature at
various locations along the seventy-third meridian. Figs. 109 to
113 are for the Urubamba Valley. Respectively they relate to
Pongo de Mainique, 1,200 feet elevation (365 m.), the gateway to
the eastern plains; Yavero, 1,600 feet (488 m.), w^here the tribu-
tary of this name enters the main stream ; Santo Anato 1,900 feet
(580 m.) ; Sahuayaco, 2,400 feet (731 m.), and Santa Ana, 3,400
feet (1,036 m.), one of the outposts of civilization beyond the East-
ern Cordillera. The meteorological conditions shown are all on
the same order. They are typical of dry season weather on the
dry floor of a montana valley. The smooth curves of clear days
are marked by high mid-day temperatures and great diurnal
range. Santo Anato is a particularly good illustration : the range
for the 24 hours is 38° F. (21.1° C). This site, too, is remarkable
as one of the most unhealthful of the entire valley. The walls of
the valley here make a sharp turn and free ventilation of the
valley is obstructed. During the wet season tertian fever pre-
vails to a degree little known east of the Cordillera, though
notorious enough in the deep valleys of the plateau. The curves
show relative humidity falling to a very low minimum on clear
days. At Santo Anato and Santa Ana, for example, it drops
below 30 per cent during the heat of the day. Afternoon cloudi-
ness, however, is a common feature even of the dry season.
A typical afternoon cloud formation is shown in Fig. 114. The
effect on temperature is most marked. It is well show^ii in the
curve for August 20 and 22 at Yavero. Cloudiness and precipita-

180

THE ANDES OF SOUTHERN PERU

17'

Clouds.'Cool

Wind 1

Clouds Sun I Hail and Snow

— I ■ ' — r 1 1 r-

squall from East. Hail

Thunder

3torn

1 I ^

now-tfe-Uai v

' '

f\y

/ '^

/ S'^

/ \

N./

1 \

[

.".

r^l

?ry I

ulb

■■ \

I
\

.••..

-5°

■•-•■

\ /

"•••\

1 l

1 W

!t Bi

lb •

'•

/•■

'^>

1:
I-

Vt.

1
1

\
— ^

-5'

50-

Noon G p.m. Midt. 6 a.m. Noon G i).m. Midt. G a.m. Noon 6 p.m.

Fig. 116.

[Haze

Clear

1
Haze

/\.

■A

, 1

V 1

-15

.."•..

..•■'

••..

Ca.m. Noon Gp.m. Midt.
Fifi. 117.

Ca.m. Noon Gp.m. Midt.

Fia. 118.

C a.m.

Fios. 1101 18 — Tcnipcriiliirc cuivcs for Idcutions in llic Maritime CordilUra and
its western vallfys, October, 1911. For construction nf curvca see Fif^s.
1091 13. Fig. 110 is for Camp 13 on the northern slope of the Maritime Cordillera
(which here runs from east to west), OctolMr l.'Mo; Fig, 117 for Cotaliuasi, October
20; Fig. 118 for Salamanca, Octcjlx-r .'{1.

tion increase during the summer months. At Santca Ana the
rainfall for the year 1894-95 amounted to 50 inches, of which 60
per cent fell between December and March. For a discussion of

METEOROLOGICAL RECORDS

181

topographic features that have some highly interesting climatic
effects in the eastern valleys of Peru see Chapter VL

Abancay, 8,000 feet (2,440 m.), in one of the inter- Andean
basins, is situated in the zone of marked seasonal precipitation.

C a.m. Noon 6 p.m. Midt. 6 a.m

Fig. 119.

6 a.m. Noon 6 p.m. Midt.
Fig. 120.

Ca.m.

Figs. 119-120 — Temperature curves for the Coast Desert, November, 1911. Fig.
119 is for Aplao, November 4 and 5; and Fig. 120 for Camand, November 9 and 10.
For construction of curves see Figs. 109 to 113.

The single day's record shows the characteristic effect of cloud
reducing the maximum temperature of the day and maintaining
the relative humidity.

Camp 13, 15,400 feet (4,720 m.), lies near the crest of the Mari-
time Cordillera a little south of Antabamba. Afternoon storms
are one of its most significant features. Cotahuasi, 9,100 feet
(2,775 m.) is near the head of a west-coast valley. Its low humid-
ity is worthy of note. That for Salamanca, 12,700 feet (3,870 m.),
is similar but not so marked.

Aplao, 3,100 feet (945 m.), and Camana at the seacoast are
stations in the west-coast desert. The interior location of the
former gives it a greater range of temperature than Camana, yet
even here the range is small in comparison with the diumal ex-
tremes of the montaiia, and the tempering effect of the sea-breeze
is clearly apparent. Camana shows a diurnal temperature range
of under 10° F. and also the high relative humidity, over 70 per
cent, characteristic of the coast.

PART II
PHYSIOGRAPHY OF THE PERUVIAN ANDES

CHAPTER XI
THE PERUVIAN LANDSCAPE

From the west coast the great Andean Cordillera appears to
have little of the regularity suggested by our relief maps. Steep
and high cliffs in many places form the border of the land and
obstruct the view ; beyond them appear distant summits rising into
the zone of clouds. Where the cliffs are absent or low, one may
look across a sun-baked, yellow landscape, generally broken by ir-
regular foothills that in turn merge into the massive outer spurs
and ranges of the mountain zone. The plain is interrupted by
widely separated valleys whose green lowland meadows form a
brilliant contrast to the monotonous browns and yellows of the
shimmering desert. In rare situations the valley trenches enable
one to look far into the Cordillera and to catch memorable
glimpses of lofty peaks capped with snow.

If the traveler come to the west-coast landscape from the well-
molded English hills or the subdued mountains of Vermont and
New Hampshire with their artistic blending of moderate profiles,
he will at first see nothing but disorder. The scenery will be im-
pressive and, in places, extraordinary, but it is apparently com-
posed of elements of the greatest diversity. All the conceivable
variations of form and color are expressed, with a predominance
of bold rugged aspects that give a majestic appearance to the
mountain-bordered shore. One looks in vain for some sign of a
quiet view, for some uniformity of features, for some landscape
that will remind him of the familiar hills of home. The Andes\
are aggressive mountains that front the sea in formidable spurs
or desert ranges. Could we see in one view their entire elevation \v

183

184 THE ANDES OF SOUTHERN PERU

from depths of over 20,000 feet beneath sea level to snowy sum-
mits, a total altitude of 40,000 feet (12,200 m.), their excessive
boldness would be more apparent. No other mountains in the
^ world are at once so continuously lofty and so near a coast which
drops off to abyssal depths.

The view from the shore is, however, but one of many which
the Andes exhibit. Seen from the base the towering ranges dis-
play a stern aspect, but, like all mountains, their highest slopes
and spurs must be crossed and re-crossed before the student is
aware of other aspects of a quite different nature. The Andes
must be observed from at least three situations: from the floors
of the deep intermontane valleys, from the intermediate slopes
and summits, and from the uppermost levels as along the range
crests and the highest passes. Strangely enough it is in the sum-
mit views that one sees the softest forms. At elevations of 14,000
to 16,000 feet (4,270 to 4,880 m.), where one would expect rugged
spurs, serrate chains, and sharp needles and horns, one comes fre-
quently upon slopes as well graded as those of a city park — grass-
covered, waste-cloaked, and w^ith gentle declivity (Figs. 121-124).

The graded, waste-cloaked slopes of the higher levels are in-
terpreted as the result of prolonged denudation in an erosion
cycle which persisted through the greater part of the Tertiary
period, and which was closed by uplifts aggregating at least sev-
eral thousands of feet. Above the level of the mature slopes rise
the ragged profiles and steep, naked declivities of the snow-capped
mountains wliicli bear residual relations to the softer forms at
their bases. They are formed upon rock masses of greater
original elevation and of higher resistance to denudation. Though
they arc dominating topographic features, they are much less ex-
tensive and significant llian the tame landscape which they sur-
mount.

Below the level of llic mature sl()])os are topograi)hic features
of ('(lual prominence: gorges and canyons u]) to 7,000 feet deep.
T\i<\ deeply inlrenclied streams are l)rok<'n ])y waterfalls and al-
most continuous rapids, the valley walls arc so abrupt that one
may, in places, roll stones down a 4,0()0-foot incline to the river

Fig. 121.

,*iiaiijra»»^*i**«*r«»«KJE?^

Fig. 122.

Fig. 121 — Looking north from the hill near Anta in the Anta basin north of
Cuzco. Typical composition of slopes and interment basins in the Central Andes.
Alluvial fill in the foreground; mature slopes in the background; in the extreme back-
ground the snow-capped crests of the Cordillera Vilcapampa.

Fig. 122 — Showing topographic conditions before the formation of the deep canyons
in the Maritime Cordillera. The view, looking across a tributary canyon of the
Antabaniba river, shows in the backgiround the main canyon above Huadquirca. Com-
pare with Fig. 60.

THE PERUVIAN LANDSCAPE

185

bed, and the tortuous trail now follows a stream in the depths of
a profound abyss, now scales the walls of a labyrinthine canyon.

The most striking elements of scenery are not commonly the
most important in physiography. The oldest and most significant
surface may be at the top of the country, where it is not seen by
the traveler or where it
cannot impress him, ex-
cept in contrast to fea-
tures of greater height
or color. The layman
frequently seizes on a
piece of bad-land erosion
or an outcrop of bright-
colored sandstone or a
cliff of variegated clays or
a snow-covered mountain as of most interest. All we can see
of a beautiful snow-clad peak is mere entertainment compared
with what subdued waste-cloaked hill-slopes may show. We do
not wish to imply that everywhere the tops of the Andes are
meadows, that there are no great scenic features in the Peruvian
mountains, or that they are not worth while. But we do wish to
say that the bold features are far less important in the interpre-
tation of the landscape.

Amid all the variable forms of the Peruvian Cordillera certain
strongly developed types recur persistently. That their impor-
tance and relation may be appreciated we shall at once name them
categorically and represent them in the form of a block diagram
(Fig. 126). The principal topographic types are as follows:

Fig. 125 — Mature upper and young lower
slopes at the outlet of the Cuzco basin.

1. An extensive system of high-level, well-graded, mature slopes, below which
are:

2. Deep canyons with steep, and in places, eliffed sides and narrow floors, and
above which are :

3. Lofty residual mountains composed of resistant, highly deformed rock, now
sculptured into a maze of serrate ridges and sharp commanding peaks.

4. Among the forms of high importance, yet causally unrelated to the other
closely associated types, are the volcanic cones and plateaus of the western Cordil-
lera.

186

THE ANDES OF SOUTHERN PERU

5. At the valley heads are a full complement of glacial features, such as cirques,
hanging valleys, reversed slopes, terminal moraines, and valley trains.

6. Finally there is in all the valley bottoms a deep alluvial fill formed during
the glacial period and now in process of dissection.

Though there are in many places special features either re-
motely related or quite unrelated to the principal enumerated
types, they belong to the class of minor forms to which relatively
small attention will be paid, since they are in general of small ex-
tent and of purely local interest.

The block diagram represents all of these features, though of

FiQ. 12G — Block diagram of the typical physiographic features of the Peruvian
Andes.

necessity somewhat more closely associated than they occur in
nature. Reference to the photographs, Figs. 121-124, will make it
clear that the diagram is somewhat ideal: on the other hand the
photographs together include all the features which the diagram
displays. In descending from any of the higher passes to the val-
ley floor one passes in succession down a stcop, well-like cirque at
a glaciated valley head, across a rocky terminal moraine, then
down a stair-like trail cut into the steep scarps which everywhere
mark the descent to tlic main valley floors, over one after another
of the confluent alluvial fans that together constitute a large part
of the valley fill, and finally down the steep sides of the inner val-
ley to the boulder-strewn bed of the ungraded river.

THE PERUVIAN LANDSCAPE 187

We shall now turn to each group of features for description
and explanation, selecting for first consideration the forms of
widest development and greatest significance — the high-level ma-
ture slopes lying between the lofty mountains which rise above
them and the deep, steep-walled valleys sunk far below them.
These are the great pasture lands of the Cordillera; their higher
portions constitute the typical puna of the Indian shepherds. In
many sections it is possible to pasture the vagrant flocks almost
anywhere upon the graded slopes, confident that the ichu, a
tufted forage grass, will not fail and that scattered brooks and
springs will supply the necessary water. At nightfall the flocks
are driven down between the sheltering walls of a canyon or in
the lee of a cliff near the base of a mountain, or, failing to reach
either of these camps, the shepherd confines his charge within the
stone walls of an isolated corral.

In those places where the graded soil-covered slopes lie within
the zone of agriculture — below 14,000 feet — they are cultivated,
and if the soil be deep and fertile they are very intensively culti-
vated. Between Anta and Urubamba, a day's march north of
Cuzco, the hill slopes are covered with wheat and barley fields
which extend right up to the summits (Fig. 134). In contrast are
the uncultivated soil-less slopes of the mountains and the bare val-
ley walls of the deeply intrenched streams. The distribution of
the fields thus brings out strongly the principal topographic rela-
tions. Where the softer slopes are at too high a level, the climatic
conditions are extreme and man is confined to the valley floors
and lower slopes where a laborious system of terracing is the first
requirement of agriculture.

The appearance of the country after the mature slopes had
been formed is brought out in Fig. 122. The camera is placed on
the floor of a still undissected, mature valley which shows in the
foreground of the photograph. In the middle distance is a valley
whose great depth and steepness are purposely hidden; beyond
the valley are the smoothly graded, catenary curves, and inter-
locking spurs of the mature upland. In imagination one sees the
valleys filled and the valley slopes confluent on the former (now

188 THE ANDES OF SOUTHERN PERU

imaginary) valley floor which extends without important change
of expression to the border of the Cordillera. No extensive cliffs
occur on the restored surface, and none now occur on large tracts
of the still undissected upland. Since the mature slopes represent
a long period of weathering and erosion, their surfaces were cov-
ered with a deep layer of soil. Where glaciation at the higher
levels and vigorous erosion along the canyons have taken place,
the former soil cover has been removed; elsewhere it is an impor-
tant feature. Its presence lends a marked softness and beauty to
these lofty though subdued landscapes.

The graded mountain slopes were not all developed (1) at the
same elevation, nor (2) upon rock of the same resistance to de-
nudation, nor (3) at the same distance from the major streams,
nor (4) upon rock of the same structure. It follows that they will
not all display precisely the same form. Upon the softer rocks at
the lowest levels near the largest streams the surface was worn
down to extremely moderate slopes with a local relief of not more
than several hundred feet. Conversely, there are quite unreduced
portions whose irregularities have mountainous proportions, and
between these extremes are almost all possible variations. Though
the term mature in a broad way expresses the stage of develop-
ment which the land had reached, post mature should be applied
to those portions which suffered the maximum reduction and now
exhibit the softest profiles. At no place along the 73rd meridian
was denudation carried to llie point of even local peneplanation.
All of the major and some of the minor divides bear residual ele-
vations and even ai)i)r().\imately plane surfaces do not exist.

Among the most important features of the mature slopes are
(1) their great areal extent — they are exhibited throughout the
whole Central Andes, (2) their persistent development upon rocks
of whatever structure or degree of hardness, and (3) their pres-
ent great elevation in s))ii(' of moderate grades iiidic-HiNc of llieir
development at a inncli lowei- nllilnde. Mature slopes of equiva-
lent form are developed in widely separated localities in the Cen-
tral Andes: in every valley about Cochabamba, Bolivia, at 10,000
feet (3,050 m.) ; at Crucero Alto in southern Peru at 14,G00 feet

TIOInT 0? 19]

:tor

-J

THE PERUVIAN LANDSCAPE

,S£A L£V5L

I5,000'_

10,000:

5.0001

S5A LEVEL

SEA LEl/FL

15,000'

~~-~"7

10^

--"

"-^^00-

..8a

•"

^ ^

CD..---

-o

CD*

..-■•_ 5,000^_

CD
O

Fig. 127 — Topographic profiles across typical valleys of southern Peru. They are
drawn to scale and the equality of gradient of the gentler upper slopes is so close that
almost any curve would serve as a composite of the whole. These curves form the
basis of the diagram, Fig. 128, whereby the amount of elevation of the Andes in late
geologic time may be determined. The approximate locations of the profiles are as
follows: 1, Antabamba; 2, Chuquibambilla; 3, upland south of Antabamba; 4, Apurimac
Canyon above Pasaje; 5, Abancay; 6, Arma (Cordillera Vilcapampa) ; 7, divide above
Huancarama; 8, Huascatay; 9, Huascatay, farther downstream; 10, Rio Pampas. The
upper valley in 8 is still undissected; 7 is practically the same; 8a is at the level
which 8 must reach before its side slopes are as gentle as at the end of the preceding
interrupted cycle.

(4,450 m.) ; several hundred miles farther north at Anta near
Cuzco, 11,000 feet to 12,000 feet (3,600 to 3,940 m.), and Fig. 129
shows typical conditions in the Vilcabamba Valley along the route
of the Yale Peruvian Expedition of 1911. The characteristic
slopes so clearly represented in these four photographs are the
most persistent topographic elements in the physiography of the
Central Andes.

190 THE ANDES OF SOUTHERN PERU

The rock masses upon which the mature slopes were formed
range from soft to hard, from stratified shales, slates, sandstones,
conglomerates, and limestones to volcanics and intrusive granites.
While these variations impose corresponding differences of form,
the graded quality of the slopes is rarely absent. In some places
the highly inclined strata are sho^^^l thinly veiled with surface
debris, yet so even as to appear artificially graded. The rock in
one place is hard granite, in another a moderately hard series of
lava flows, and again rather weak shales and sandstones.

Proof of the rapid and great uplift of certain now lofty moun-
tain ranges in late geologic time is one of the largest contribu-
tions of physiography to geologic history. Its validity now rests
upon a large body of diversified evidence. In 1907 I crossed the
Cordillera Sillilica of Bolivia and northern Chile and came upon
clear evidences of recent and great uplift. The conclusions pre-
sented at that time were tested in the region studied in 1911, 500
miles farther north, with the result that it is now possible to state
more precisely the dates of origin of certain prominent topo-
graphic forms, and to reconstruct the conditions which existed
before the last great uplift in which the Central Andes were born.
The relation to this general problem of the forms under discus-
sion will now be considered.

The gradients of the mature slopes, as we have already seen,
are distinctly moderate. In the Anta region, over an area several
hundred square miles in extent, they run from several degrees to
20° or 30°. Ten-degree slopes are perhaps most common. If the
now dissected slopes be reconstructed on the basis of many
clinometer readings, pliotographs, and topographic maps, the re-
sult is a series of profiles as in Fig. 127. If, further, the restored
slopes be coordinated over an extensive area the gradients of the
resulting valkjy floors will run from 3° to 10°. Finally, if these
valley floors be extended westward to the Pacific and eastward
to the Amazon basin, they will be found about 5,000 feet above
sea level and 4,000 feet above the eastern plains. (For explana-
tion of method and data employed, see the accompanying figures
127-128). It is, therefore, a justifiable conclusion that since the

THE PERUVIAN LANDSCAPE

191

^ 2 > S ;c ^

ij W) <l

•^ i;

> o

^ f" h

« o ?

c i °

^ C r-

^ -

O C

bo to ^ a>

S '5 -o 5

o s-

2 s,

o JJ ? S

c aj

iJ '^l t3

o ^ C

o tn

S O 2i

tt) tD ^

&C ci

O o o i-

p be

pC to

--J > M

C 2 =*

PL| c B

12 S "
+3 -k^ -^

f=H

Is 1^.5

I 3 u_ o

' ^ a,

I ^ § 5

' 'tc H o

I O a>

L ^ a p)

I o .g g

' -5 "a -^

: o 2 ^

' "^ ^ ^

^ _j «

t-r 3 >

j^ -M ^

n W) ^

? « ,

o o -jf •

^ >- o

en &I C3

Ph ^ r-,
C) cS "^

:;5 "P O

-»->
•(-*

-T- .2 o

.tj

-4->

—I

-C ^ 03

2 ii

-c £ -S

C- -tJ C -iJ

192 THE ANDES OF SOUTHERN PERU

formation of the slopes the Andes have been uplifted at least a
mile, or, to put it in another way, the Andes at the time of forma-
tion of the mature slopes were at least a mile lower than they are
at present.

Further proof of recent and great uplift is afforded by the
deeply intrenched streams. After descending the long graded
slopes one comes upon the cliffed canyons with a feeling of con-
sternation. The effect of powerful erosion, incident upon uplift,
is heightened by the ungraded character of the river bed. Falls
and rapids abound, the river profiles suggest tumultuous descents,
and much time vnll elapse before the river beds have the regular
and moderate gradients of the streams draining the mature sur-
face before uplift as shown in the profiles by the dotted lines rep-
resenting the restored valley floors of the older cycle. Since the
smooth-contoured landscape was formed great changes have taken
place. The streams have changed from completely graded to al-
most completely ungraded profiles; in place of a subdued land-
scape we now have upland slopes intersected by mile-deep can-
yons; the high-level slopes could not have been formed under
existing conditions, for they are being dissected by the present
streams.

Since the slopes of the land in general undergo progressive
changes in the direction of flatter gradients during a given geo-
graphical cycle, it follows that with the termination of one cycle
and the beginning of another, two sets of slopes will exist and that
the gradients of the two will be unlike. The result is a break in
the descent of the slopes from high to low levels to which tlie name
** topographic unconformity" is now applied. It will be a promi-
nent feature of the landscape if tlie higher, older, and Hatter gradi-
lents have but little declivity, and the gradients of the lower
younger slopes ;ire very steep. In those places where ilic iclicf
of the first cycle was still great at Ihe lime of uplift, the erosion
forms of the second cycle may not be differentiated from those of
the first, since both are marked by steep gradients. In the Cen-
tral Andes the change in gradient l)etwcen the higher and lower
slopes is generally well marked. It occurs at variable heights

piTI
RECT
bsTG-LI

lA^BC-

■=>^\

THE PERUVIAN LANDSCAPE 193

above the valley floors, though rarely more than 3,000 feet above\
them. In the more central tracts, far from the main streams and \
their associated canyons, dissection in the present erosion cycle
has not yet been initiated^ the mature slopes are still intact, and /
a topographic unconformity has not yet been developed. The
higher slopes are faced with rock and topped with slowly moving
waste. Ascent of the spur end is by steep zigzag trails ; once ihd\
top is gained the trail runs along the gentler slopes without spe-j
cial difficulties.

It is worth noting at this point that the surface of erosion still
older than the mature slopes herewith described appears not to
have been developed along the seventy-third meridian of Peru, or
if developed at one time, fragments of it no longer remain. The
last well-developed remnant is southwest of Cuzco, Fig. 130. I
have elsewhere described the character and geographic distribu-
tion of this oldest recognizable surface of the Central Andes. ^
Southern Peru and Bolivia and northern Chile display its features
in what seems an unmistakable manner. The best locality yet found
is in the Desaguadero Valley between Ancoaqui and Concordia.
There one may see thousands of feet of strongly inclined sedi-
ments of varying resistance beveled by a well-developed surface
of erosion whose preserval is owing to a moderate rainfall and to
location in an interior basin.-

The highest surface of a region, if formed during a prolonged
period of erosion, becomes a surface of reference in the determina-
tion of the character and amount of later crustal deformations,
having somewhat the same functions as a key bed in stratigraphic
geology. Indeed, concrete physiographic facts may be the only
basis for arguments as to both epeirogenic and orogenic move-
ments. The following considerations may show in condensed form-
the relative value of physiographic evidence :

1. If movements in the earth's crust are predominantly dou-n-

^ The Physiography of the Central Andes, Am. Journ. Sci., Vol. 40, 1909, pp. 197-217
and 373-402.

° Results of an Expedition to the Central Andes, Bull. Am. Geog. Soc. Vol. 40, 1914.
Figs. 28 and 29.

194. THE ANDES OF SOUTHERN PERU

ward, sedimentation may be carried on continuously and a clear
geologic record may be made.

2. Even if crustal movements are alternately downward and
upward, satisfactory conclusions may be drawn from both (a) the
nature of the buried surfaces of erosion, and (b) the alternating
character of the sediments.

3. If, however, the deformative processes effect steady or in-
termittent uplifts, there may be no sediments, at least within the
limits of the positive crustal units, and a geologic record must be
derived not from sedimentary deposits but from topographic
forms. We speak of the lost intervals represented by strati-
graphic breaks or unconformities and conunonly emphasize our
ignorance concerning them. The longest, and, from the human
standpoint, the most important, break in the sedimentary record
is that of the present wherever degradation is the predominant
physiographic process. Unlike the others the lost interval of the
present is not lost, if we may so put it, but is in our possession,
and may be definitely described as a concrete thing. It is the
physiography of today.

Even where long-buried surfaces of erosion are exposed to
view, as in northern Wisconsin, where the Pie-Cambrian paleo-
plain projects from beneath the Paleozoic sediments, or, as in New
Jersey and southeastern Pennsylvania, where the surface devel-
oped on the crystalline rocks became by depression the floor of the
Triassic and by more recent uplift and erosion has been exposed
to view, — even in such cases the exposures are of small extent and
give us at best but meager records. In short, many of the breaks
in the geologic record arc of such long duration as to make im-
perative the use of physiographic principles and methods. The
great Appalachian System of eastern North America lias been a
land area practically since the end of llio Paleozoic. Tu the Cen-
tral Andes the "lost interval," from the standpoint of the sedi-
mentary record, dates from llio close of the Cretaceous, except in
a few local intermont ])asins partially filled willi Tertiary or
Pleistocene deposits. Physiographic interpretations, therefore,
serve the double purpose of supplying a part of the geologic rec-

THE PERUVIAN LANDSCAPE 195

ord while at the same time forming a basis for the scientific study
of the surface distribution of living forms.

The geologic dates of origin of the principal topographic forms
of the Central Andes may be determined with a fair degree of
accuracy. Geologic studies in Peru and Bolivia have emphasized
the wide distribution of the Cretaceous formations. They consist
principally of thick limestones above and sandstones and con-
glomerates below, and thus represent extensive marine submer-
gence of the earth's crust in the Cretaceous where now there are
very lofty mountains. The Cretaceous deposits are everywhere
strongly deformed or uplifted to a great height, and all have been
deeply eroded. They were involved, together with other and much
older sediments, in the erosion cycle which resulted in the devel-
opment of the widely extended series of mature slopes already
described. From low scattered island elevations projecting above
sea level, as in the Cretaceous period, the Andes were transformed
by compression and uplift to a rugged mountain belt subjected
to deep and powerful erosion. The products of erosion Avere in
part swept into the adjacent seas, in part accumulated on the
floors of intermont basins, as in the great interior basins of Titi-
caca and Poopo.

Since the early Tertiary strata are themselves deformed from
once simple and approximately horizontal structures and sub-
jected to moderate tilting and faulting, it follows that mountain-
making movements again affected the region during later Terti- ^
ary. They did not, however, produce extreme effects. They did
stimulate erosion and bring about a reorganization of all the /
slopes with respect to the new levels.

This agrees closely with a second line of evidence which rests
upon an independent basis. The alluvial fill which lies upon all the
canyon and valley floors is of glacial origin, as shown by its inter-
locking relations with morainal deposits at the valley heads. It is
now in process of dissection and since its deposition in the Pleis-
tocene had been eroded on the average about 200 feet. Clearly,
to form a 3,000-foot canyon in hard rock requires much more time
than to deposit and again partially to excavate an alluvial fill sev-

196 THE ANDES OF SOUTHERN PERU

eral hundred feet deep. Moreover, the glacial material is coarse
throughout, and was built up rapidly and dissected rapidly. In
most cases, furthermore, coarse material at the bottom of the gla-
cial series rests directly upon the rock of a narrow and ungraded
valley floor. From these and allied facts it is concluded that there
is no long time interval represented by the transitions from de-
grading to aggrading processes and back again. The early Pleisto-
cene, therefore, seems quite too short a period in which to produce
the bold forms and effect the deep erosion which marks the period
between the close of the mature cycle and the beginnings of deposi-
tion in the Pleistocene.

I The alternative conclusion is that the greater part of the canyon
/cutting was effected in the late Tertiary, and that it continued into
the early Pleistocene until further erosion was halted by changed
climatic conditions and the augmented delivery of land waste to
all the streams. The final development of the well-graded high-
level slopes is, therefore, closely confined to a small portion of the
Tertiary. The closest estimate which the facts support appears
to be Miocene or early Pliocene. It is clear, however, that only the
culmination of the period can be definitely assigned. Erosion was
in full progress at the close of the Cretaceous and by middle
Tertiary had effected vast changes in the landscape. The Tertiary
strata are marked by coarse basal deposit and by thin and very
fine top deposits. Though their deformed condition indicates a
period of crustal disturbance, the Tertiary beds give no indica-
tion of wholesale transformations. They indicate chiefly tilting
and moderate and normal faulting. The previously developed ef-
fects of erosion wore, therefore, not radically modified. The sur-
face was thus in large measure prepared by erosion in the early
Tertiary for its final condition of maturity reached during the
early Pliocene.

It seems appropriate, in concluding this cliapter, to summarize
in its main outlines the physiography of southern Peru, partly to
condense the extended discussion of the preceding paragraphs,
and partly to supply a l)ackground for the tliree chapters tliat
follow. The outstanding features are broad plateau areas sepa-

THE PERUVIAN LANDSCAPE 197

rated by well-defined "Cordilleras." The plateau divisions are
not everywhere of the same origin. Those southwest of Cuzco
(Fig. 130), and in the Anta Basin (Fig. 124), northwest of Cuzco, ^
are due to prolonged erosion and may be defined as peneplane
surfaces uplifted to a great height. They are now bordered on
the one hand by deep valleys and troughs and basins of erosion
and deformation; and, on the other hand, by residual elevations
that owe their present topography to glacial erosion superim-
posed upon the normal erosion of the peneplane cycle. The
residuals form true mountain chains like the Cordillera Vilcanota
and Cordillera Vilcapampa; the depressions due to erosion or
deformation or both are either basins like those of Anta and
Cuzco or valleys of the canyon type like the Urubamba canyon;
the plateaus are broad rolling surfaces, the punas of the Peruvian
Andes.

There are two other types of plateaus. The one represents a
mature stage in the erosion cycle instead of an ultimate stage ; the
other is volcanic in origin. The former is best developed about
Antabamba (Figs. 122 and 123), where again deep canyons and
residual ranges form the borders of the plateau remnants. The
latter is well developed above Cotahuasi and in its simplest form
is represented in Fig. 133. Its surface is the top of a vast accumu-
lation of lavas in places over a mile thick. While rough in detail
it is astonishingly smooth in a broad view (Fig. 29). Above it
rise two types of elevations : first, isolated volcanic cones of great
extent surrounded by huge lava flows of considerable relief; and
second, discontinuous lines of peaks where volcanic cones of less
extent are crowded closely together. The former type is displayed
on the Coropuna Quadrangle, the latter on the Cotahuasi and La
Cumbre Quadrangles.

So high is the elevation of the lava plateau, so porous its soil,
so dry the climate, that a few through-flowing streams gather the
drainage of a vast territory and, as in the Grand Canyon country
of our West, they have at long intervals cut profound canyons.
The Arma has cut a deep gorge at Salamanca; the Cotahuasi runs
in a canyon in places 7,000 feet deep ; the Majes heads at the edge V

198 THE ANDES OF SOUTHERN PERU

of the volcanic field in a steep amphitheatre of majestic propor-
tions.

Finally, we have the plateaus of the coastal zone. These are
plains with surfaces several thousand feet in elevation separated
by gorges several thousand feet deep. The Pampa de Sihuas is an
illustration. The post-maturely dissected Coast Range separates
it from the sea. The pampas are in general an aggradational
product formed in a past age before uplift initiated the present
canyon cycle of erosion. Other plateaus of the coastal zone are
erosion surfaces. The Tablazo de lea appears to be of this type.
That at Arica, Chile, near the southern boundary of Peru, is
demonstrably of this type with a border on which marine plana-
tion has in places given rise to a broad terrace effect.^

» The Physiography of the Central Andes, by Isaiah Bowman; Am. Journ. Sci., Vol.
28, 1909, pp. 197-217 and 373-402. See especially, ibid., Fig. 11, p. 216.

Fig. 129.

Fig. l;]U.

Fig. 129 — Composition of slopes at Piiquiura, Vilcabaniba Valley, elevation 9,000
feet (2,740 m. ). The second prominent spur entering the valley on the left has a
flattish top unrelated to the rock structure. Like the spurs on the riglit its blunt end
and flat top indicate an earlier erosion cycle at a lower elevation.

Fig. 130 — Inclined Paleozoic strata truncated I)y an undulating surface of erosion
at 15,000 feet, southwest of Cuzco.

I'Ki. ).'{! 'IVrr;i(('(l viillcy hlopcs at Iluii yiiacolus, ( ul
(3,500 III.). SoliiniiiDi in in tlic back^'niiiiid < >m tlic llnoi <
trwH grow. At HiiayiiacotaH corn ami iKitatocs air I lie il
compoHt'd almost entirely of hivii. I lien- arc over a Ihiik
5,000 (o 7.000 feet Ihick.

aliuasi

f 111.' (

lied

Valley. :
'(ilaliMa''i
iducts. ■
a iui- llnw

I l,:i(t() feet

iiyiiii fruit

section is

ggregating

CHAPTER XII

THE WESTERN ANDES: THE MARITIME CORDILLERA
OR CORDILLERA OCCIDENTAL

The Western or Maritime Cordillera of Peru forms part of
the great volcanic field of South America which extends from
Argentina to Ecuador. On the walls of the Cotahuasi Canyon
(Fig. 131), there are exposed over one hundred separate lava
flows piled 7,000 feet deep. They overflowed a mountainous relief,
completely burying a limestone range from 2,000 to 4,000 feet
high. Finally, upon the surface of the lava plateau new moun-
tains were formed, a belt of volcanoes 5,000 feet (1,520 m.) high
and from 15,000 to 20,000 feet (4,570 to 6,100 m.) above the sea.
There were vast mud flows, great showers of lapilli, dust, and
ashes, and with these violent disturbances also came many changes
in the drainage. Sixty miles northeast of Cotahuasi the outlet of
an unnamed deep valley was blocked, a lake was formed, and sev-
eral hundred feet of sediments were deposited. They are now
w^asting rapidly, for they lie in the zone of alternate freezing and
thawing, a thousand feet and more below the snowline. Some of
their bad-land forms look like the solid bastions of an ancient
fortress, while others have the delicate beauty of a Japanese
temple.

Not all the striking effects of vulcanism belong to the remote
geologic past. A day's journey northeast of Huaynacotas are a
group of lakes only recently hemmed in by flows from the small
craters thereabouts. The fires in some volcanic craters of the
Peruvian Andes are still active, and there is no assurance that
devastating flows may not again inundate the valleys. In the
great Pacific zone or girdle of volcanoes the earth's crust is yet
so unstable that earthquakes occur every year, and at intervals of
a few years they have destructive force. Cotahuasi was greatly
damaged in 1912; Abancay is shaken every few years; and the
violent earthquakes of Cuzco and Arequipa are historic.

199

200 THE ANDES OF SOUTHERN PERU

On the eastern margin of the volcanic country the flows thin
out and terminate on the summit of a limestone (Cretaceous)
plateau. On the western margin they descend steeply to the nar-
row west-coast desert. The greater part of the lava dips beneath
the desert deposits; there are a few intercalated flows in the
deposits themselves, and the youngest flows — ^limited in number —
have extended do^vn over the inner edge of the desert.

The immediate coast of southern Peru is not volcanic. It is
composed of a very hard and ancient granite-gneiss which forms
a narrow coastal range (Fig. 171). It has been subjected to very
long and continued erosion and now exhibits mature erosion forms
of great uniformity of profile and declivity.

From the outcrops of older rocks beneath the lavas it is pos-
sible to restore in a measure the pre-volcanic topography of the
Maritime Cordillera. In its present altitude it ranges from several
thousand to 15,000 feet above sea level. The unburied topography
has been smoothed out; the buried topography is rough (Figs. 29
and 16C). The contact lines between lavas and buried surfaces in
the deep Majes and Cotahuasi valleys are in places excessively
serrate. From this, it seems safe to conclude that the period of
vulcanism was so prolonged that great changes in the unburied
relief were effected by the agents of erosion. Thus, while the
dominant process of volcanic upbuilding smoothed the former
rough topography of the Maritime Cordillera, erosion likewise
measurably smoothed the present high extra-volcanic relief in the
central and eastern sections. The effect has been to develop a
broad and sufficiently smooth aspect to the summit topography of
the entire Andes to give them a plateau character. Afterward the
whole mountain region was uplifted about a mile above its former
^level so that at present it is also continuously lofty.

Tlic zone of most intense volcanic action does not coincide with
the liighest part of ilie pre- volcanic topography. If the pre-vol-
canic relief were even in a very general way like that which would
be exhibited if the lavas were now removed, we should have to say
that the chief volcanic outbursts took place on the western flank
of an old and deeply dissected limestone range.

WESTERN ANDES: MARITIME CORDILLERA 201

The volume of the lavas is enormous. They are a mile and a
half thick, nearly a hundred miles wide, and of indefinite extent
north and south. Their addition to the Andes, therefore, has
greatly broadened the zone of lofty mountains. Their passes are
from 2,000 to 3,000 feet higher than the passes of the eastern
Andes. They have a much smaller number of valleys sufficiently
deep to enjoy a mild climate. Their soil is far more porous and
dry. Their vegetation is more scanty. They more than double
the difficulties of transportation. And, finally, their all but un-
populated loftier expanses are a great vacant barrier between
farms in the warm valleys of eastern Peru and the ports on the
west coast.

The upbuilding process was not, of course, continuous. There
were at times intervals of quiet, and some of them were long
enough to enable streams to become established. Buried valleys
may be observed in a number of places on the canyon walls, where
subsequently lava flows displaced the streams and initiated new
drainage systems. In these quiet intervals the weathering agents
attacked the rock surfaces and formed soil. There were at least
three or four such prolonged periods of weathering and erosion
wherein a land surface was exposed for many thousands of years,
stream systems organized, and a cultivable soil formed. No evi-
dence has been found, however, that man was there to cultivate
the soil.

The older valleys cut in the quiet period are mere pygmies be-
side the giant canyons of today. The present is the time of domi-
nant erosion. The forces of vulcanism are at last relatively quiet.
Recent flows have occurred, but they are limited in extent and in
effects. They alter only the minor details of topography and
drainage. "Were it not for the oases set in the now deep-cut can-
yon floors, the lava plateau of the Maritime Cordillera w^ould
probably be the greatest single tract of unoccupied volcanic coun-
try in the world.

The lava plateau has been dissected to a variable degree. Its
high eastern margin is almost in its original condition. Its west-
ern margin is only a hundred miles from the sea, so that the

202 THE ANDES OF SOUTHERN PERU

streams have steep gradients. In addition, it is lofty enough to
have a moderate rainfall. It is, therefore, deeply and generally
dissected. "Within the borders of the plateau the degree of dissec-
tion depends chiefly upon position with respect to the large
streams. These were in turn located in an accidental manner.
The repeated upbuilding of the surface by the extensive outflow
of liquid rock obliterated all traces of the earlier drainage. In the
Cotahuasi Canyon the existing stream, working down through a
mile of lavas, at last uncovered and cut straight across a moun-
tain spur 2,000 feet high. Its course is at right angles to that
pursued by the stream that once drained the spur. It is note-

( worthy that the Cotahuasi and adjacent streams take northerly
courses and join Atlantic rivers. The older drainage was directly
west to the Pacific. Thus, vulcanism not only broadened the
Andes and increased their height, but also moved the continental
divide still nearer the west coast.

(The glacial features of the western or Maritime Cordillera are
of small extent, partly because vulcanism has added a considera-
ble amount of material in post-glacial time, partly because the cli-
imate is so exceedingly dry that the snowline lies near the top of
'the country. The slopes of the volcanic cones are for the most
part deeply recessed on the southern or shady sides. Above 17,500
feet (5,330 m.) the process of snow and ice excavation still con-
tinues, but the tracts that exceed this elevation are confined to the
loftiest peaks or their immediate neighborhood. There is a dis-
tinct difference between the glacial forms of the eastern or moister
and the western or dryer flanks of this Cordillera. Only peaks
like Coropuna and Solimana near the western border now bear or
/ever bore snowficlds and ghiciers. By coutrnst the eastern aspect
is hea\ily glaciated. On La Cumbro (L)iin<li'aiigle, tliere is a huge
glacial trough at 10,000 feet (4,870 m.). .-iikI fliis oxtonds with rami-
licntioiis uj) into tlic snowficlds tli.'il foiMiicfly iiicliidcd llic liiglicst
coinilry. Prolonged gljicial erosion ])roduced Ji full set of topo-
gra})hic forms characteristic of the work of Alpine glaciers. Thus,
each of the main mountain chains that make up the Andean sys-
tem has, lilc ill'' system as a whole, a relatively more-dry and a

WESTERN ANDES: MARITIME CORDILLERA 203

relatively less-dry aspect. The snowline is, therefore, canted
from west to east on each chain as well as on the system. How-
ever, this effect is combined with a solar effect in an unequal way.
In the driest places the solar factor is the more efficient and the
snowline is there canted from north to south.

CHAPTER XIII

THE EASTERN ANDES: THE CORDILLERA VILCAPAMPA

The culminating range of the eastern Andes is the so-called
Cordillera Vilcapampa. Its numerous, sharp, snow-covered peaks
are visible in every summit view from the central portion of the
Andean system almost to the western border of the Amazon basin.
Though the range forms a water parting nearly five hundred miles
long, it is crossed in several places by large streams that flow
through deep canyons bordered by precipitous cliffs. The Uru-
bamba between Torontoy and Colpani is the finest illustration.
For height and ruggedne&s the Vilcapampa mountains are among
the most noteworthy in Peru. Furthermore, they display glacial
features on a scale unequaled elsewhere in South America north
of the ice fields of Patagonia.

GLACIERS AND GLACIAX. FORMS

One of the most impressive sights in South America is a
tropical forest growing upon a glacial moraine. In many places
in eastern Bolivia and Peru the glaciers of the Ice Age were from
5 to 10 miles long — almost the size of the Mer de Glace or the
famous Rhone glacier. In the Juntas Valley in eastern Bolivia
the tree line is at 10,000 feet (3,050 m.), but the terminal moraines
lie several thousand feet lower. In eastern Peru the glaciers in
many places extended down nearly to the tree line and in a few
places well below it. In the Cordillera Vilcapampa vast snow-
fields and glacier systems were spread out o\or a summit area
as broad as the Southern Appalachians. The snowfields have
since shrunk to the higher mountain recesses; the glaciers have
retreated for the most part to the vjilley heads or the cirque
floors; and the lower limit of perpetual snow has been raised to
15,500 feet.

'JMl

mmi^iiff^iv^^

■ Hi IWitTTTirilill lUlWlli'ift

Fig. 132.

Fig. l;

Fig. 132 — Recessed volcanoes in the right background and eroded tuffs, ash beds,
and lava flows on the left. Maritime Cordillera above Cotahuasi.

Fig. 133 — The summit of the great lava plateau above Cotahuasi on the trail to
Antabamba. The lavas are a mile and a half in thickness. The elevation is 16,000
feet. Hence the volcanoes in the background, 17,000 feet above sea level, are mere
hills on the surface of the lofty plateau.

Fig. 134.

Fio. i;}").

Via. I.'(4 — SoutliweHlcrn iisjicct of tli<' Coidillri;! \ ilcniiMinpn lictwcm Aii<!i Jiiid
IrubiMiiba from Lake HiiiM|)o. KuKU<'(l Hunuiiil ((i|)n^'rii|iliy in tlir IpiicU^'roimd, graded
poHt-matiirc nlopfs in tin- iniddlf distaiicf, and Holiitinn lake in iinic^toni' in the fore-
ground.

Fio. 135— Summit view, (V)rdill«'rii \iiciii>:ini|.;i. 'i'licn' :irc litt.in <,'liicicis rcpro-
spntcd in tlii.'< plioto^rrapli. 'flu- fiimcrii sljindH on (lie siiinmil (if a minor disidc in tlic
zone of nivation.

EASTERN ANDES: CORDILLERA VILCAPAMPA 205

These features are surprising because neither Whymper ^ nor
Wolf ^ mentions the former greater extent of the ice on the vol-
canoes of Ecuador, only ten or twelve degrees farther north.
Moreover, Reiss ^ denies that the hypothesis of universal climatic
change is supported by the facts of a limited glaciation in the
High Andes of Ecuador ; and J. W. Gregory " completely overlooks
published proof of the existence of former more extensive glaciers
elsewhere in the Andes :

"... the absence not only of any traces of former more ex-
tensive glaciation from the tropic^ as in the Andes and Kiliman-
djaro, but also from the Cape." |He says further: ''In spite of
the extensive glaciers now in existence on the higher peaks of the
Andes, there is practically no evidjence of their former greater
extension." ( !) ^t

AVhymper spent most of his time' in exploring recent volcanoes
or those recently in eruption, hence did not have the most favora-
ble opportunities for gathering significant data. Reiss was car-
ried off his feet by the attractiveness of the hypothesis ^ relating
to the effect of glacial denudation on the elevation of the snowline.
Gregory appeared not to have recognized the work of Hettner on
the Cordillera of Bogota and of Sievers " and Acosta on the Sierra
Nevada de Santa Marta in northern Colombia.

The importance of the glacial features of the Cordillera Vilca-
pampa developed on a great scale in very low latitudes in the
southern hemisphere is twofold : first, it bears on the still unset-
tled problem of the universality of a colder climate in the Pleis-
tocene, and, second, it supplies additional data on the relative de-
pression of the snowline in glacial times in the tropics. Snow-

' Travels Amongst the Great Andes of the Equator, 1892.

^ Geografia y Geologia del Ecuador, 1892.

» Das Hochgebirge dcr Republik Ecuador, Vol. 2, 2 Ost-Cordillera, 1902, p. 162.

* Contributions to the Geology of British East Africa; Ft. 1, The Glacial Geology
of Mount Kenia, Quart. Journ. Geol. Soc, Vol. 50, 1894, p. 523.

° See especially A. Penck (Penck and Briickner), Die Alpen im Eiszeitalter, 1909,
Vol. 1, p. 6, and I. C. Russell, Glaciers of Mount Rainier, 18th Ann. Rcp't, U. S. Geol.
Surv., 1896-97, Sect. 2, pp. 384-385.

• Die Sierra Nevada de Santa Marta und die Sierra de PerijS, Zcitschrift der
Gesellschaft fur Erdkunde zu Berlin, Vol. 23, 1888, pp. 1-158.

206 THE ANDES OF SOUTHERN PERU

clad mountains near the equator are really quite rare. Mount
Kenia rising from a great jungle on the equator, Kilimandjaro
-v^-ith its hvo peaks, Kibo and Mawenzi, two hundred miles farther
south, and Ingomwimbi in the Euwenzori group thirty miles north
of the equator, are the chief African examples. A few mountains
from the East Indies, such as Kinibalu in Borneo, latitude 6° north,
have been found glaciated, though now without a snow cover. In
,higher latitudes evidences of an earlier extensive glaciation have
been gathered chiefly from South America, whose extension 13°
north and 56° south of the equator, combined with the great height
of its dominating Cordillera, give it unrivaled distinction in the
study of mountain glaciation in the tropics.

Furthermore, mountain summits in tropical lands are delicate
climatic registers. In this respect they compare favorably with
the inclosed basins of arid regions, where changes in climate are
clearly recorded in shoreline phenomena of a familiar kind. Lofty
mountains in the tropics are in a sense inverted basins, the lower
snowline of the past is like the higher shoreline of an interior
basin ; the terminal moraines and the alluvial fans in front of them
are like the alluvial fans above the highest strandline; the present
snow cover is restricted to mountain summits of small areal ex-
tent, just as the present water bodies are restricted to the lowest
portions of the interior basin ; and successive retreatal stages are
marked by terminal moraines in the one case as they are marked
in the other by flights of terraces and beach ridges,

I made only a rapid reconnaissance across the Cordillera Vilca-
pampa in the winter season, and cannot pretend from my limited
observations to solve many of the problems of the field. The data
are incorporated chiefly in the chapter on Glacial Features.
In this place it is proposed to describe only the more prominent
glacial features, leaving to later expeditions the detailed descrip-
tions upon wliich tlie soliilion of some of the larger problems must
depend.

/ At ('hoquolira three prominent stages in \h(\ retreat of the ice
arc recorded. Th(! lowermost stage is represented by the great fill
of morainic and outwash material at the junction of the Cheque-

EASTERN ANDES: CORDILLERA VILCAPAMPA 207

lira, and an unnamed valley farther south at an elevation of
11,500 feet (3,500 m.). A mile below Choquetira a second moraine
appears, elevation 12,000 feet (3,658 m.), and immediately above
the village a third at 12,800 (3,900 m.). The lowermost moraine
is well dissected, the second is ravined and broken but topo-
graphically distinct, the third is sharp-crested and regular. A
fourth though minor stage is represented by the moraine at the
snout of the living glacier
and still less important
phases are represented in
some valleys — possibly the
record of post-glacial
changes of climate. Each
main moraine is marked by
an important amount of
outwash, the first and third
moraines being associated
with the greatest masses.
The material in the moraines
represents only a part of
that removed to form the
successive steps in the valley
profile. The lowermost one
has an enormous volume,
since it is the oldest and

Fig. 136 — Glacial sculpture on the south-
western flank of the Cordillera Viloapampa.
Flat-floored valleys and looped terminal mo-
raines below and glacial steps and hanging
valleys are characteristic. The present snow-
flelds and glaciers are shown by dotted contours.

was built at a time when the valley was full of waste. It is fronted
by a deep fill, over the dissected edge of which one may descend
800 feet in half an hour. It is chiefly alluvial in character, whereas
the next higher one is composed chiefly of bowlders and is fronted
by a pronounced bowlder train, which includes a remarkable
perched bowlder of huge size. Once the valley became cleaned
out the ice would derive its material chiefly by the slower
process of plucking and abrasion, hence would build much smaller
moraines during later recessional stages, even though the stages
were of equivalent length.

There is a marked difference in the degree of dissection of the

208 THE ANDES OF SOUTHERN PERU

moraines. The lowermost and oldest is so thoroughly dissected
as to exhibit but little of its original surface. The second has
been greatly modified, but still possesses a ridge-like quality and
marks the beginning of a noteworthy flattening of the valley
gradient. The third is as sharp-crested as a roof, and yet was
built so long ago that the flat valley floor behind it has been modi-
fied by the meandering stream. From this point the glacier re-
treated up-valley several miles (estimated) without leaving more
than the thinnest veneer on the valley floor. The retreat must,
therefore, have been rapid and without even temporary halts until
the glacier reached a position near that occupied today. Both the-
present ice tongues and snowfields and those of a past age are
emphasized by the presence of a patch of scrub and woodland that
extends on the north side of the valley from near the snowline
do^^^l over the glacial forms to the lower valley levels.

The retreatal stages sketched above would call for no special
comment if they were encountered in mountains in northern lati-
tudes. They would be recognized at once as evidence of successive
periodic retreats of the ice, due to successive changes in tempera-
ture. To understand their importance when encountered in very
low latitudes it is necessary to turn aside for a moment and con-
sider two rival hypotheses of glacial retreat. First wc have the
hypothesis of periodic retreat, so generally applied to terminal
moraines and associated outwash in glaciated mountain valleys.
This implies also an advance of the ice from a higher position,
the whole taking place as a result of a climatic change from
warmer to colder and back again to warmer.

But evidences of more extensive mountain glaciation in the
past do not in themselves prove a change in climate over the whole
earth, i ii an epoch of fixed climate a glacier system may so deeply
and thoroughly erode a mountain mass, that the former glaciers
may eitli'r diminish in size or disappear altogether. As the work
of excavalioii piocoeds, the catchmout basins are sunk to, and at
last below, \\\o, snowline; broad tributary spurs whose snows
j nourish the glaciers, may l)e reduced to narrow or skeleton ridges
V with little snow to contribute to the valleys on eithcM- liaiid; the

Fig. 137.

Fig. 138.

Fig. 137 — Looking up a spurless flat-floored glacial trough near the Chucuito pass
in the Cordillera Vilcaparapa from 14,200 feet (-1,330 m.). Note the looped terminal
and lateral moraines on the steep valley wall on the left. A stone fence from wall to
wall serves to inclose the flock of the mountain shepherd.

Fig. 138 — Terminal moraine in the glaciated Choquetira Valley below Choquetira.
The people who live here have an abundance of stones for building corrals and stone
houses. The upper edge of the timber belt (cold timber line) is visible beyond the
houses. Elevation 12,100 feet (3,G90 m.).

EASTERN ANDES: CORDILLERA VILCAPAMPA 209

glaciers retreat and at last disappear. There would be evidences
of glaciation all about the ruins of the former loftier mountain,
but there would be no living glaciers. And yet the climate might
remain the same throughout.

It is this "topographic" hypothesis that Eeiss and Stiibel
accept for the Ecuadorean volcanoes. Moreover, the volcanoes of
Ecuador are practically on the equator — a very critical situation
when we wish to use the facts they exhibit in the solution of such
large problems as the contemporaneous glaciation of the two
hemispheres, or the periodic advance and retreat of the ice over
the whole earth. This is not the place to scrutinize either their
facts or their hypothesis, but I am under obligations to state very
emphatically that the glacial features of the Cordillera Vilca-
pampa require the climatic and not the topographic hypothesis.
Let us see why.

The differences in degree of dissection and the flattening
gradient up-valley that we noted in a preceding paragraph leave
no doubt that each moraine of the bordering valleys in the Vilca-
pampa region, represents a prolonged period of stability in the
conditions of topography as well as of temperature and precipita-
tion. If change in topographic conditions is invoked to explain
retreat from one position to the other there is left no explanation
of the periodicity of retreat which has just been established. If
a period of cold is inaugurated and glaciers advance to an ulti-
mate position, they can retreat only through change of climate
effected either by general causes or by topographic development
to the point where the snowfields become restricted in size. In
the case of climatic change the ice changes are periodic. In the
case of retreat due to topographic change there should be a steady
or non-periodic falling back of the ice front as the catchment
basins decrease in elevation and the snow-gathering ridges tribu-
tary to them are reduced in height.

Further, the matterhorns of the Cordillera Vilcapampa are not
bare but snow-covered, vigorous glaciers several miles in length
and large snowfields still survive and the divides are not aretes
but broad ridges. In addition, the last two moraines, composed

210

THE ANDES OF SOUTHERN PERU

of very loose niJPl^l, are well preserved. They indicate clearly
that the time since^»ir fonnation has witnessed no wholesale
topographic change. tI (1) no important topographic changes
ihave taken place, and (2) a vigorous glacier lay for a long period
back of a given moraine, and (3) suddenly retreated several
j^miles and again became stable, we are left without confidence
in the application of the topographic hypothesis to the glacial

features of the Vilcapampa
region. Glacial retreat may
be suddenly begun in the
case of a late stage of topo-
graphic development, but it
should be an orderly retreat
marked by a large number
of small moraines, or at
least a plentiful strewing of
the valley floor with debris.

The number of moraines
in the various glaciated val-
leys of the Cordillera Vil-
capampa differ, owing to
differences in elevation and
to the variable size of the
catchment basins. All val-
leys, however, display the
same sudden change from moraine to moraine and the same
characteristics of gradient. In all of them \\u^ lowermost
moraine is [ilways more deeply eroded tlian the higher
moraines, in all of them glacial erosion was sufficiently pro-
longed greatly to modify llic valley walls, scour out lake basins,
or bi-oad flat valley floors, develop cirques, aretes, and pinnacled
ridges in I i mi led nuinlier. hi some, glaciation was carried to the
point where only skeletoTi divides remained, in most places broad
massive ridges or mountain knots persist. In spite of all these
differences successive moraines were formed, separated by long
stretches eilliei- tliinly coNcred with lill or exposing bare rock.

Scale of Miles

— 1—

Fig. 139 — Glacial features on the eastern
slopes of the Cordillera Vilcapampa.

EASTERN ANDES: CORDILLERA VILCAPAMPA 211

In examining this group of features it i|ji(|iportant to rec-
02-nize the essential fact that though thi«iumber of moraines

varies from valley to valley, the differen|p? in character between
the moraines at low and at high elevations in a single valley are
constant. It is also clear that everywhere the ice retreated and
advanced periodically, no matter with what topographic features
it was associated, whether those of maturity or of youth in the
glacial cycle. We, therefore, conclude that topographic changes
had no significant part to pl^y in the glacial variations in the
Cordillera Vilcapampa. '~

The country west of the Cordillera Vilcapampa had been re-
duced to early topographic maturity before the Ice Age, and then
uplifted with only moderate erosion of the masses of the inter-
fluves. That on the east had passed through the same sequence
of events, but erosion had been carried much farther. The reason
for this is found in a strong climatic contrast. The eastern is
the windward aspect and receives much more rain than the west-
ern. Therefore, it has more streams and more rapid dissection.
The result was that the eastern slopes were cut to pieces rapidly
after the last great regional uplift ; the broad interfluves were nar-
rowed to ridges. The region eastward from the crest of the
Cordillera to the Pongo de Mainique looks very much like the
western half of the Cascade Mountains in Oregon — the summit
tracts of moderate declivity are almost all consumed.

The effect of these climatic and topographic contrasts is mani-
fested in strong contrasts in the position and character of the gla-
cial forms on the opposite slopes of the range. At Pampaconas
on the east the lowermost terminal moraine is at least a thousand
feet below timber line. Between Vilcabamba pueblo and Puquiura
the terminal moraine lies at 11,200 feet (3,414 m.). By contrast
the largest Pleistocene glacier on the western slope, nearly twelve
miles long, and the largest along the traverse, ended several miles
below Choquetira at 11,500 feet (3,504 m.) elevation, or just at the
timber line. Thus, the steeper descents of the eastern side of the
range appear to have carried short glaciers to levels far lower
than those attained by the glaciers of the western slope.

212

THE ANDES OF SOUTHERN PERU

Scalp i>t \lilts

¥ i

M'Soiroccoc*^c

W/^

X^/;-

•i-V I67S4 O

It seems at first strange that the largest glaciers were west
of the divide between the Urubamba and the Apurimac, that is, on
the relatively dry side of the range. The reason lies in a strik-
ing combination of topo-
graphic and climatic condi
tions. Snow is a mobile
form of precipitation that is
shifted about by the wind
like a sand dune in the
desert. It is not required,
like water, to begin a down-
hill movement as soon as it
strikes the earth. Thus, it
is a noteworthy fact that
snow drifting across the
divides may ultimately cause
the largest snowfields to lie
where the least snow ac-
tually falls. This is illus-
trated in the Bighorns of
Wyoming and others of our
w^estern ranges. It is, how-
ever, not the wet snow near
the snowline, but chiefly the
dry snow of higher altitudes
that is affected. AVhat is
now the dry or leeward side
of the Cordillera appears in glacial times to have actually re-
ceived more snow than the wet windward side.

The topography conspired to increase this contrast. In place
of many streams, direct descents, a dispersion of snow in many
valleys, as on Hk; cast, the western slopes had indirect descents,
gentler valley profiles, and that higher degree of concentration of
drainage whicli naturally goes with topographic maturity. For
example, there is nothing in the oast to compare with the big spur-
less valley near the pass above Anna. The side walls were so

/(''

1' >«■

^^^lgf%i^;;

flii\i^»

Fig. 140 — Glacial sculpture in the heart
of the Cordillera Vilcapampa. In places the
topography ha.'< so high a relief that the glaciers
aeem almost to overhang the valleys. See Figs.
90 and 179 for photographs.

EASTERN ANDES: CORDILLERA VILCAPAMPA 213

extensively trimmed that the valley was turned into a trough.
The floor was smoothed and deepened and all the tributary gla-
ciers were either left high up on the bordering slopes or entered
the main valley with very steep profiles ; their lateral and terminal
moraines now hang in festoons on the steep side walls. Moreover,
the range crest is trimmed from the west so that the serrate sky-
line is a feature rarely seen from eastern viewpoints. This may
not hold true for more than a small part of the Cordillera. It was
probably emphasized here less by the contrasts already noted
than by the geologic structure. The eastward-flowing glaciers
descended over dip slopes on highly inclined sandstones, as at
Pampaconas. Those flowing westward worked either in a jointed
granite or on the outcropping edges of the sandstones, where the
quarrying process known as glacial plucking permitted the devel-
opment of excessively steep slopes.

There are few glacial steps in the eastern valleys. The west-
tern valleys have a marvelous display of this striking glacial fea-
ture. The accompanying hachure maps show them so well that
little description is needed. They are from 50 to 200 feet high.
Each one has a lake at its foot into which the divided stream
trickles over charming Avaterfalls. All of them are clearly asso-
ciated with a change in the volume of the glacier that carved the
valley. Wherever a tributary glacier entered, or the side slopes
increased notably in area, a step was formed. By retreat some
of them became divided, for the process once begun would push
the step far up valley after the manner of an extinguishing water-
fall.

The retreat of the steps, the abrasion of the rock, and the sap-
ping of the cirques at the valley heads excavated the upper val-
leys so deeply that they are nearly all, as W. D. Johnson has put
it, "do^vn at the heel." Thus, above Arma, one plunges suddenly
from the smooth, grassy glades of the strongly glaciated valley
head down over the outer slopes of the lowermost terminal
moraine to the steep lower valley. Above the moraine are fine
pastures, in the steep valley below are thickets and rocky defiles.
There are long quiet reaches in the streams of the glaciated valley

214 THE ANDES OF SOUTHERN PERU

heads besides pretty lakes aud marshes. Below, the stream is
swift, almost torrential. Arma itself is built upon alluvial de-
posits of glacial origin. A mile farther down the valley is con-
stricted and steep-walled — really a canyon.

Though the glaciers have retreated to the summit region, they
are by no means nearing extinction. The clear blue ice of the
glacier descending from Mt. Soiroccocha in the Arma Valley
seems almost to hang over the precipitous valley border. In
curious contrast to its suggestion of cold and storm is the patch
of dark green woodland which extends right up to its border. An
earthquake might easily cause the glacier to invade the woodland.
Some of the glaciers between Choquetira and Arma rest on
terminal moraines whose distal faces are from 200 to 300 feet
high. The ice descending southeasterly from Panta Mt. is a good
illustration. Earlier positions of the ice front are marked by
equally large moraines. The one nearest that engaged by the liv-
ing glacier confines a large lake that discharges through a gap in
the moraine and over a waterfall to the marshy floor of the valley.

Retreat has gone so far, however, that there are only a few
large glacier systems. Most of the tributaries have withdrawn
toward their snowfields. In place of the twenty distinct glaciers
now lying between the pass and the terminal moraine below Cho-
quetira, there was in glacial times one great glacier with twenty
minor tributaries. The cirques now partly filled with damp snow
must then have been overflowing with dry snow above and ice be-
low. Some of the glaciers were over a thousand feet thick; a few
were nearly two thousand feet thick, and the cirques that fed
them held snow and ice at least a half mile deep. Such a remark-
ably complete set of glacial features only 700 miles from the
equator is striking evidence of the moist climate on the windward
eastern part of tlic groat Andean Cordillera, of llio universal
change in climate in the glacial period, and of the powerful domi-
nating effocts of ico erosion in this region of unsurpassed Alpine
relief.

EASTERN ANDES: CORDILLERA VILCAPAMPA

215

THE VILCAPAMPA BATHOLITII AND ITS TOPOGRAPHIC EFFECTS

The main axis of the Cordillera Vilcapampa consists of granite)
in the form of a batholith between crystalline schists on the one/
hand (southwest), and Carboniferous limestones and sandstones
and Silurian shales and slates on the other (northeast). It is nol
a domal uplift in the region in which it was observed in 1911, bi

PAMPACONAS -
---/VALLEY

CORDILLERA, VILCAPAMPA

;;;;;;^!^^3=^ GRANITE

,,---;^;;^Z^^;;;^^ P R P H Y R Y

N.(>v E.

IL.__SAN D S T N E .^"'^^

- — "Z-^ ■

Fig. 141 — Composite geologic section on the nortlieastern border of tlic Cordillera
Vilcapampa, in the vicinity of Pampaconas, to show the deformative effects of the
granite intrusion. There is a limited amount of limestone near the border of the
Cordillera. Both limestone and sandstone are Carboniferous. See Appendix B. See
also Figs. 142 and 146. The section is about 15 miles long.

an axial intrusion, in places restricted to a narrow belt not more
than a score of miles across. As Ave should expect from the
variable nature of the invaded material, the granite belt is not
uniform in width nor in the character of its marginal features.
In places the intrusion has produced strikingly little alteration
of the country rock; in other localities the granite has been
injected into the original material in so intimate a manner as
almost completely to alter it, and to give rise to a very broad
zone of highly metamorphosed rock. Furthermore, branches were
developed so that here and there tributary belts of granite
extend from the main mass to a distance of many miles. Out-
lying batholiths occur whose common petrographic character and
similar manner of occurrence leave little doubt that they are
related abyssally to a common plutonic mass.

The Vilcapampa batholith has two highly contrasted borders,
whether w^e consider the degree of metamorphism of the country
rock, the definition of the border, or the resulting topographic
forms. On the northeastern ridge at Colpani the contact is so
sharp that the outstretched arms in some places embrace typical

216

THE ANDES OF SOUTHERN PERU

the Vilcapampa intrusion on the north-
eastern border of the Cordillera. The
deformed strata are heavy-bedded sand-
stones and shales and the igneous rocks
are chiefly granites with bordrring porphy-
ries. Looking northwest near Puquiura.
For conditions near Pampaconas, looking
in the opposite direction, see Fig. 141. For
conditions on the other side of the Cordil-
lera see Fig. 14G.

granite on the one hand and almost unaltered shales and slates on
the other. Inclusions or xenoliths of shale are common, however,
ten and fifteen miles distant, though they are prominent features
in a belt only a few miles wide. The lack of more intense contact
effects is a little remarkable in view of the altered character of
EASTERN BORDER RANGES ^he iuclusious, all of which are
crystalline in contrast to the fis-
sile shales from which they are
Fig. 142— The deformative efiFects of chiefly derived. Inclusions with-
in a few inches of the border
fall into a separate class, since
they show in general but trifling
alteration and preserve their
original cleavage planes. It ap-
pears that the depth of the in-
trusion must have been rela-
tively slight or the intrusion sudden, or both shallow and sudden,
conditions which produce a narrow zone of metamorphosed ma-
terial and a sharp contact.

The relation between shale and granite at Colpani is shown
in Fig. 143. Projections of granite extend several feet into the
shale and slate and generally
end in blunt barbs or knobs.
In a few places there is an in-
timate mixture of irregular
slivers and blocks of crystal-
lized sediments in a granitic
groundmass, with shai-p lines
of demarcation between igneous
and included iriatcrial. Tiic
contact is vertical for at least
several miles. It is probable;

Fkj. 14:5 — Relation of granite intru-
sion to schist on the northeastern border
of the Vilcapampa batholith near the
bridge of Colpnni, lower end of ilie granite
Canyon of Toronloy. The sections are
from 16 to 25 feet high and represent con-
ditions at difTerent levels along the well-
defined contact.

that other localities on the con

tact exhibit much greater modification and iiuasion of llie weak
shales and slates, but at Colpani the phenomena are both simple
;iiid restricted in development.

EASTERN ANDES: CORDILLERA VILCAPAMPA 217

The highly mineralized character of the bordering sedimentary
strata, and the presence of numbers of complementary dikes,
nearly identical in character to those in the parent granite now
exposed by erosion over a broad belt roughly parallel to the con-
tact, supplies a basis for the inference that the granite may under-
lie the former at a slight depth, or may have had far greater meta-
morphic effects upon its sedimentary roof than the intruded
granite has had upon its sedimentary rim.

The physiographic features of the contact belt are of special
interest. No available physiographic interpretation of the topog-
raphy of a batholith includes a discussion of those topographic
and drainage features that are related to the lithologic character
of the intruded rock, the manner of its intrusion, or the depth of
erosion since intrusion. Yet each one of these factors has a dis-
tinct topographic effect. We shall, therefore, turn aside for a
moment from the detailed discussion of the Vilcapampa region
to an examination of several physiographic principles and then
return to the main theme for applications.

It is recognized that igneous intrusions are of many varieties
and that even batholithic invasions may take place in rather
widely different ways. Highly heated magmas deeply buried be-
neath the earth's surface produce maximum contact effects, those
nearer the surface may force the strata apart without extreme
lithologic alterations of the displaced beds, while through the
stoping process a sedimentary cover may be largely absorbed and
the magmas may even break forth at the surface as in ordinary
vulcanism. If the sedimentary beds have great vertical variation
in resistance, in attitude, and in composition, there may be af-
forded an opportunity for the display of quite different effects
at different levels along a given contact, so that a great variety
of physical conditions will be passed by the descending levels of
erosion. At one place erosion may have exposed only the summit
of the batholith, at another the associated dikes and sheets and
ramifying branches may be exposed as in the zone of fracture, at
a third point the original zone of flowage may be reached with
characteristic marginal schistosity, while at still greater depths

218 THE ANDES OF SOUTHERN PERU

there may be uncovered a highly metamorphosed rim of resistant
sedimentary rock.

The mere enumeration of these variable structural features is
sufficient to show how variable we should expect the associated
land forms to be. Were the forms of small extent, or had they
but slight distinction upon comparison with other erosional ef-
fects, they would be of little concern. They are, on the contrary,
very extensively developed; they affect large numbers of lofty
mountain ranges besides still larger areas of old land masses sub-
jected to extensive and deep erosion, thus laying bare many batho-
liths long concealed by a thick sedimentary roof.

The differences between intruded and country rock dependent
upon these diversified conditions of occurrence are increased or
diminished according to the history of the region after batholithic
invasion takes place. Regional metamorphism may subsequently
induce new structures or minimize the effects of the old. Joint
systems may be developed, the planes widely spaced in one group
of rocks giving rise to monolithic masses very resistant to the
agents of weathering, while those of an adjacent group may be so
closely spaced as greatly to hasten the rate of denudation. There
may be developed so great a degree of schistosity in one rock as
to give rise (with vigorous erosion) to a serrate topography; on
the other hand the forms developed on the rocks of a batholith
may be massive and coarse-textured.

To these diversifying conditions may be added many others
involving a large part of the field of dynamic geology. It will
perhaps suffice to mention two others : the stage of erosion and
the special features related to climate. If a given intrusion has
been accompanied by an important amount of uplift or marginal
compression, vigorous erosion may follow, whereupon a chance
will be offered for the development of the greatest contrast in the
degree of boldness of topographic forms developed upon rocks of
unequal resistance. Ultimately these contrasts will diminish in
intensity, as in the cnsf of ;ill roi^noiml (lirfercuccs of relief, with
progress toward tho end of the normal cycle of erosion. If pene-
plnnntion onsuf, only feeble topographic difforcucos may mark

O o i^

-^ £! ^

«;

;-i

to o*

5 g

•sa

•>**>.■.. .♦^' ''..*■ y

&H CS O P

h-.

i=!

"a,

C
ci

"a.

-4^

"a,

o
>>

'm
an

,_4

-o

u
ta

o
"5

■5

>»

■^

'^f

_>s

:«

EASTERN ANDES: CORDILLERA VILCAPAMPA 219

the line of contact which was once a prominent topographic fea-
ture. With reference to the effects of climate it may be said sim-
ply that a granite core of batholithic origin may extend above the
snowline or above timber line or into the timbered belt, whereas
the invaded rock may occur largely below these levels with obvi-
ous differences in both the rate and the kind of erosion affecting
the intruded mass.

If we apply the foregoing considerations to the Cordillera
Vilcapampa, we shall find some striking illustrations of the prin-
ciples involved. The invasion of the granite was accompanied by
moderate absorption of the displaced rock, and more especially
by the marginal pushing aside of the sedimentary rim. The im-
mediate effect must have been to give both intruded rock and coun-
try rock greater height and marked ruggedness. There followed
a period of regional compression and torsion, and the develop-
ment of widespread joint systems with strikingly regular features.
In the Silurian shales and slates these joints are closely spaced;
in the granites they are in many places twenty to thirty feet
apart. The shales, therefore, offer many more points of attack
and have weathered down into a smooth-contoured topography
boldly overlooked along the contact by w^alls and peaks of granite.
In some cases a canyon ivall a mile high is developed entirely on
two or three joint planes inclined at an angle no greater than 15°.
The effect in the granite is to give a marked boldness of relief,
nowhere more strikingly exhibited than at Huadquina, below
Colpani, where the foot-hill slopes developed en shales and slates
suddenly become moderate. The river flows from a steep and all
but uninliabited canyon into a broad valley whose slopes are dot-
ted with the terraced chacras, or farms, of the mountain Indians.

The Torontoy granite is also homogeneous while the shales
and slates together with their more arenaceous associates occur
in alternating belts, a diversity which increases the points of at-
tack and the complexity of the forms. Tending toward the same
result is the greater hardness of the granite. The tendency of the
granite to develop bold forms is accelerated in lofty valleys dis-
posed about snow-clad peaks, where glaciers of great size once

220 THE ANDES OF SOUTHERN PERU

existed, and where small glaciers still linger. The plucking action
of ice has an excellent chance for expression, since the granite
may be quarried cleanly without the production of a large amount
of spoil which would load the ice and diminish the intensity of its
plucking action.

As a whole the Central Andes passed through a cycle of ero-
sion in late Tertiary time which was interrupted by uplift after
the general surface had been reduced to a condition of topo-
graphic maturity. Upon the granites mature slopes are not de-
veloped except under special conditions (1) of elevation as in the
small batholith above Chuquibambilla, and (2) where the granite
is itself bordered by resistant schists which have upheld the sur-
iface over a broad transitional belt. Elsewhere the granite is
marked by exceedingly rugged forms : deep steep-walled canyons,
precipitous cirques, matterhorns, and bold and extended escarp-
ments of erosion. In the shale belt the trails run from valley to
valley in every direction without special difficulties, but in the
granite they follow the rivers closely or cross the axis of the
range by carefully selected routes which generally reach the limit
of perpetual snow. Added interest attaches to these bold topo-
graphic forms because of the ruins now found along the canyon
walls, as at Torontoy, or high up on the summit of a precipitous
spur, as at Machu Picchu near the bridge of San Miguel.

The Vilcapampa batholith is bordered on the southwest by a
series of ancient schists with which the granite sustains quite dif-
ferent relations. No sharp dividing line is visible, the granite
extending along the planes of foliation for such long distances as
in places to appear almost intorbcdded with tlie scliists. The re-
lation is all the more striking in view of the trifling intrusions
effected in the case of the seemingly much weaker shales on the
opposite contact. Nor is llio metamorphism of flic invaded rock
limited to simple intrusion. For several miles beyond tlie zone
of iiiffTisfT effects tlie schists have been enriched with quartz to
such an extent that their original darker color has been changed
to light gray or dull white. At a distance they may even appear
as homogeneous and liglit-colored as the granite. At distant

EASTERN ANDES: CORDILLERA VILCAPAMPA 221

points the schists assume a darker hue and take on the characters
of a rather typical mica schist.

It is probable that the Vilcapampa intrusion is one of a family
of batholiths which further study may show to extend over a
much larger territory. The trail west of Abancay was followed
quite closely and accidentally crosses two small batholiths of
peculiar interest. Their limits were not closely followed out, but

Fig. 146 — Deformative effects on limestone strata of the granite intrusion on the
southwestern border of the Vilcapampa batholith above Chuquibambilla. Fig. 147 is on
the same border of the batholith several miles farther northwest. The granite mass
on the right is a small outlier of the main batholith looking south. The limestone
is Cretaceous. See Appendix C for locations.

were accurately determined at a number of points and the remain-
ing portion of the contact inferred from the topography. In the
case of the larger area there may indeed be a connection west-
ward with a larger mass which probably constitutes the ranges
distant some five to ten miles from the line of traverse.

These smaller intrusions are remarkable in that they appear
to have been attended by little alteration of either invading or
invaded rock, though the granites were observed to become dis-
tinctly more acid in the contact zone. Space was made for them
by displacing the sedimentary cover and by a marked shortening
of the sedimentary rim through such structures as overthrust
faults and folds. The contact is observable in a highly meta-
morphosed belt about twenty feet wide, and for several hundred
feet more the granite has absorbed the limestone in small amounts
with the production of new minerals and the development of a dis-
tinctly lighter color. The deformative effects of the batholithic
invasion are shoAvn in their gross details in Figs. 141, 142, and 146 ;
the finer details of structure are represented in Fig. 147, which is
drawn from a measured outcrop above Chuquibambilla.

It will be seen that we have here more than a mere crinkling,

222

THE ANDES OF SOUTHERN PERU

Fig. 147 — Overthrust folds in detail on the
southwestern border of the Vilcapampa batho-
lith near Chuquibambilla. The section is fifteen
feet high. Elevation, 13,100 feet (4,000 m.).
For comparison with the structural effects of
the Vilcapampa intrusion on the northeast see
Fig. 142.

such as the mica schists of the Cordillera Vilcapampa display.
The diversified sedimentary series is folded and faulted on a large
scale vrith broad structural undulations visible for miles along the
abrupt valley walls. Here and there, however, the strata become
weaker generally through the thinning of the beds and the more
rapid alternation of hard and soft layers, and for short distances

they have absorbed notable
amounts of the stresses in-
duced by the igneous intru-
sions. In such places not
only the structure but the
composition of the rock
shows the effects of the in-
trusion. Certain shales in
the section are carbonaceous
and in all observed cases the
organic matter has been
transformed to anthracite, a
condition generally associated witli a certain amount of minute
mashing and a cementation of both limestone and sandstone.

The granite becomes notably darker on approach to the north-
eastern contact near Colpani; the proportion of ferro-magnesian
minerals in some cases is so large as to give a distinctly black
color in sharp contrast to the nearly white granite typical of the
central portion of the mass. Large masses of shale foundered in
tlie invading magma, and upon fusion gave rise to huge black
masses impregnated with quartz and in places smeared or in-
jected with granite ma.gma. Everywhere the granite is marked
by numbers of black masses which appear at first sight to be ag-
gregations of dark minerals normal to the granite and due to dif-
ferentiation processes at llic time of crystallization. Tt is, liow-
cvor, noteworthy llial tlicso increase rapidly in number on ap-
proacli <o the contact, until in tlic last half-mile they appear to
grade into llio slialo incluHioiis. 11 ?ii;iy, therefore, be doubted that
thoy ni-f aggi-cgatioiis. l-'roiii lliclr universal distribution, their
uniform character, and llirir nunkcd increase in numbers on ap-

EASTERN ANDES: CORDILLERA VILCAPAMPA 223

proach to lateral contacts, it may reasonably be inferred that they
represent foundered masses of country rock. Those distant from
present contacts are in almost all cases from a few inches to a
foot in diameter, while on approach to lateral contacts they are
in places ten to twenty feet in width, as if the smaller areas rep-
resented the last remnants of large inclusions engulfed in the
magma near the upper or roof contact. They are so thoroughly
injected with silica and also with typical granite magma as to
make their reference to the country rock less secure on petro-
graphical than on purely distributional grounds.

A parallel line of evidence relates to the distribution of com-
plementary dikes throughout the granite. In the main mass of
the batholith the dikes are rather evenly distributed as to kind
with a slight preponderance of the dark-colored group. Near the
contact, however, aplitic dikes cease altogether and great num-
bers of melanocratic dikes appear. It may be inferred that we
have in this pronounced condition suggestions of strong influence
upon the final processes of invasion and cooling of the granite
magma, on the part of the country rock detached and absorbed
by the invading mass. It might be supposed that the indicated
change in the character of the complementary dikes could be
ascribed to possible differentiation of the granite magma w^hereby
a darker facies would be developed toward the Colpani contact.
It has, however, been pointed out already that the darkening of
the granite in this direction is intimately related to a marked in-
crease in the number of inclusions, leaving little doubt that the
thorough digestion of the smaller masses of detached shales is
responsible for the marked increase in the number and variety
of the ferro-magnesian and special contact minerals.

Upon the southwestern border of the batholith the number of
aplitic dikes greatly increases. They form prominent features,
not only of the granite, but also of the schists, adding greatly to
the strong contrast between the schist of the border zone and that
outside the zone of metamorphism. In places in the border
schists, these are so numerous that one may count up to twenty
in a single view, and they range in size from a few inches to ten

224 THE ANDES OF SOUTHERN PERU

or fifteen feet. The greater fissility of the schists as contrasted
with the shales on the opposite or eastern margin of the batholith
caused them to be relatively much more passive in relation to the
granite magma. They were not so much torn off and incorporated
in the magTua, as they were thoroughly injected and metamor-
phosed. Added to this is the fact that they are petrographically
more closely allied to the granite than are the shales upon the
northeastern contact.

CHAPTER XIV
THE COASTAL TERRACES

Along the entire coast of Peru are upraised and dissected ter-
races of marine origin. They extend from sea level to 1,500 feet
above it, and are best displayed north of Mollendo and in the des-
ert south of Payta. The following discussion relates to that por- \
tion of the coast .between Mollendo and Camana. 1

At the time of the development of the coastal terraces the land
was in a state of temporary equilibrium, for the terraces were
cut to a mature stage as indicated by the following facts: (1) the
terraces have great mdth — from one to five and more miles; (2)
their inner border is straight, or, where curves exist, they are
broad and regular; (3) the terrace tops are planed off smoothly
so that they now have an even gradient and an almost total ab-
sence of rock stacks or unreduced spurs; (4) the mature slopes
of the Coast Range, strikingly uniform in gradient and stage of
development (Fig. 148), are perfectly organized with respect to
the inner edge of the terrace. They descend gradually to the ter-
race margin, showing that they were graded with respect to sea
level when the sea stood at the inner edge of the highest terrace.

From the composition and even distribution of the thick-bed-
ded Tertiary deposits of the desert east of the Coast Range, it is
concluded that the precipitation of Tertiary time was greater than
that of today (see p. 261). Therefore, if the present major streams
reach the sea, it may also be concluded that those of an earlier
period reached the sea, provided the topography indicates the per-
fect adjustment of streams to structure. Lacustrine sediments
are absent throughout the Tertiary section. Such through-flowing
streams, discharging on a stable coast, would also have mature
valleys as a consequence of long uninterrupted erosion at a fixed
level. The Majes river must have cut through the Coast Range

226 THE ANDES OF SOUTHERN PERU

at Camana then as now. Likewise the Vitor at Quilca must have
cut straight across the Coast Eange. An examination of the sur-
face leading down from the Coast Eange to the upper edge of
these valleys fully confimis this deduction. Flowing and well-
graded slopes descend to the brinlv of the inner valley in each
case, where they give way to the gorge walls that continue the
descent to the valley floor.

Confirmatory evidence is found in the wide Majes Valley at
Cantas and Aplao. (See the Aplao Quadrangle for details.)
Though the observer is first impressed with the depth of the val-
ley, its width is more impressive still. It is also clear that two
periods of erosion are represented on its walls. Above Aplao the
valley walls swing off to the west in a great embayment quite in-
explicable on structural grounds; in fact the floor of the embay-
ment is developed across the structure, w^hich is here more dis-
ordered than usual. The same is true below Cantas, as seen from
the trail, which drops over two scarps to get to the valley floor.
The upper, widely opened valley is correlated with the latter part
of the period in which were formed the mature terraces of the
coast and the mature slopes bordering the larger valleys where
they cross the Coast Range.

After its mature development the well-graded marine terrace
was upraised and dissected. The deepest and broadest incisions
in it were made where the largest streams crossed it. Shallower
and narrower valleys were formed where the smaller streams that
headed in the Coast Range flowed across it. Their depth and
breadth was in general proportional to the height of that part of
the Coast Range in which tlieir headwaters lay and to the size of
their catchment basins.

AVhen the dissection of the terrace had progressed to the point
\s here about one-third of il liad hoen destroyed, there came depres-
sion aTid IIk' (1('i)()sitl(»ii of I Miocene or early Pleistocene sands,
gravels, and loenl elay beds. l*jverywhere the valleys were partly
or wliolly filled niid over broad stretches, as in tlio vicinity of
stream mouths and upon lower ))()rtions of the tciTaee, extensive
deposits were laid down. Tiie largest deposits lie several hours'

FlQ. 148.

. iMJiaC^iaM ;

4*fc:.^ Tf?^aiM»^% . 1 .^.<8^Ba^^

Fig. 149.

Fig. 148 — The Coast Range between Mollendo and Arequipa at the end of June,
1911. There is practically no grass and only a few dry shrubs. The fine network over
the hill slopes is composed of interlacing cattle tracks. The cattle roam over these
hills after the rains which come at long intervals. (See page 141 for description of
the rains and the transformations they efiect. For example, in October, 1911, these hills
were covered with grass. )

Fig. 149 — The great marine terrace at Mollendo. See Fig. 150 for profile.

THE COASTAL TERRACES

ride south of Camana, where locally they |§
attain a thickness of several hundred feet.
Their upper surface was well graded and
they show a prolonged period of deposi-
tion in which the former coastal terrace
was all but concealed.

The uplift of the coast terrace and its
subsequent dissection bring the physical
history down to the present. The uplift
was not uniform ; three notches in the ter-
race show more faintly upon the granite-
gneiss where the buried rock teri-ace has
been swept clean again, more strongly
upon the softer superimposed sand. They
lie below the 700-foot contour and are in-
significant in appearance beside the slopes
of the Coast Eange or the ragged bluff of
the present coast.

The effect of the last uplift of the coast
was to impel the Majes River again to cut
down its lower course nearly to sea level.
The Pliocene terrace deposits are here en-
tirely removed over an area several
leagues wide. In their place an extensive
delta and alluvial fan have been formed.
At first the river undoubtedly cut down to
base level at its mouth and deposited the
cut material on the sea floor, now shoal,
for a considerable distance from shore.
We should still find the river in that posi-
tion had other agents not intervened. But
in the Pleistocene a great quantity of
waste was swept into the Majes Valley,
whereupon aggradation began; and in the
middle and lower valley it has continued
down to the present.

227

^ — ]

._::::::::::::

8 .

[f)

s::::::::::::±

8._

■*

}

8.. t

t^ 1 I

§::::::::::!::::

8 i"Y

s: :-^-""

-t::::::::::

" -/

Q J

o ,

§"t-f

8 T

§:_. :

2 t

[

u\: t

gyniiiiiiiiiiii

o a

CO h

00 «

o o

2 <-•

^ ^

I a

< bo

o ^

s c a

- -^ o

o 2 -u
o r <u

•si

228

THE ANDES OF SOUTHERN PERU

F108. 151-)r,4 - TIk-hc. four diagnuns rci>rcHciit (lie jjliysical hiaiory inid ilii' coirc-
Hponding phyaiographic dpvcl(.|.mpnt of the coastal r.gioii of Peru between CainanJi and
Mollendo. The scdim.-ntary beds in the background of the first diagram are hyix)-
thetiral and are nupposed to correHpon.l to \h'- .luart/.it.^H of (h- Majes Valley at Aplao.

THE COASTAL TERRACES 229

The effect has been not only the general aggradation of the
valley floor, but also the development of a combined delta and
superimposed alluvial fan at the valley mouth. The seaward ex-
tension of the delta has been hastened by the gradation of the
shore between the bounding headlands, thus giving rise to marine
marshes in which every particle of contributed waste is firmly
held. The plain of Camana, therefore, includes parts of each of
the following: a delta, a superposed alluvial fan, a salt-water
marsh, a fresh-water marsh, a series of beaches, small amounts
of piedmont fringe at the foot of Pliocene deposits once trimmed
by the river and by waves, and extensive tracts of indefinite fill.
(See the Camana Quadrangle for details.)

With the coastal conditions now before us it will be possible
to attempt a correlation between the erosion features and the de-
posits of the coast and those of the interior. An understanding
of the comparisons will be facilitated by the use of diagrams,
Figs. 151-154, and by a series of concise summary statements.
From the relations of the figure it appears that :

1. The Tertiary deposits bordering the Majes Valley east of
the Coast Range were in process of deposition when the sea
planed the coastal terrace (Fig. 151).

2. A broad mature marine terrace without stacks or sharply
alternating spurs and reentrants (though the rock is a very re-
sistant granite) is correlated with the mature grades of the Coast
Range, with which they are integrated and with the mature pro-
files of the main Cordillera.

3. Such a high degree of topographic organization requires
the dissection in the late stages of the erosion cycle of at least
the inner or eastern border of the piedmont deposits of the des-
ert, largely accumulated during the early stages of the cycle.

4. Since the graded slopes of the Coast Range on the one side
descend to a former shore whose elevation is now but 1,500 feet
above sea level, and since only ten to twenty miles inland on the
other side of the range, the same kind of slope extends beneath
Tertiary deposits 4,000 feet above sea level, it appears that ag-
gradation of the outer (or western) part of the Tertiary deposits

230 THE ANDES OF SOUTHERN PERU

on the eastern border of the Coast Range continued do^^'n to the
end of the cycle of erosion, though

5. There must have been an outlet to the sea, since, as we
have already seen, the water supply of the Tertiary was greater
than that of today and the present streams reach the sea. More-
over, the mature upper slopes and the steep lower slopes of the
large valleys make a pronounced topographic unconformity, show-
ing two cycles of valley development.

6. Upon uplift of the coast and dissection of the marine ter-
races at the foot of the Coast Range, the streams cut deep trenches
on the floors of their former valleys (Fig. 152) and removed (a)
large portions of the coast terrace, and (b) large portions of the
Tertiary deposits east of the Coast Range.

7. Depression of the coastal terrace and its partial burial
meant the drowning of the loAver Majes Valley and its partial fill-
ing with marine and later with terrestrial deposits. It also
brought about the partial filling by stream aggradation of the
middle portion of the valley, causing the valley fill to abut sharply
against the steep valley walls. (See Fig. 155.)

8. Uplift and dissection of both the terrace and its overlying
sediments would be accompanied by dissection of the former val-
ley fill, provided that the waste supply was not increased and that
the uplift was regional and approximately equal throughout —
not a bowing up of the coast on the one hand, or an excessive bow-
ing up of the mountains on the other. But the waste supply has
not remained constant, and the uplift has been greater in the
Cordillera than on the coast. Let us proceed to the proof of these
two conclusions, since upon them depends the interpretation of the
later physical history of the coastal valleys.

It is known Hint tlic I'lcistoceno was a time of augmented
waste delivery. At tlic lie; id of tlio broadly opened Majes Valley
there was deposited a huge mass of extremely coarse waste sev-
eral hundred foot doop and several milos long. Forward from it,
intorstratified willi its ontci- margin, and continuing tlio same al-
luvial grade, is a still greater mass of finer material whieli de-
scends to lower levels. 'I'lio fine nintorial is deposited on the floor

2 -s "^

"^ «3 1

S C a3

O c3

S =* .5

tie 2

Ph ^

o3 =5

>1 rt

c/:'

-u

i-t

CS «

THE COASTAL TERRACES 231

of a valley cut into Tertiary strata, hence it is younger than the
Tertiary. It is now, and has been for some time past, in process
of dissection, hence it was not formed under present conditions of
climate and relief. It is confidently assigned to the Pleistocene,
since this is definitely known to have been a time of greater pre-
cipitation and waste removal on the mountains, and deposition on
the plains and the floors of mountain valleys. Such a conclusion
appears, even on general grounds, to be but a shade less reliable
than if we were able to find in the upper Majes Valley, as in so
many other Andean valleys, similar alluvial deposits interlocked
with glacial moraines and valley trains.

In regard to the second consideration — the upbowing of the
Cordillera — it may be noted that the valley and slope profiles of
the main Cordillera shown on p. 191, when extended toward the
margin of the mountain belt, lie nearly a mile above the level of
the sea on the west and the Amazon plains on the east. The evi-
dence of regional bowing thus afforded is checked by the depths of
the mountain valleys and the stream profiles in them. The
streams are now sunk from one to three thousand feet below their
former level. Even in the case of three thousand feet of erosion
the stream profiles are still ungraded, the streams themselves are
almost torrential, and from one thousand to three thousand feet
of vertical cutting must still be accomplished before the profiles
will be as gentle and regular as those of the preceding cycle of
erosion, in which were formed the mature slopes now lying high
above the valley floors.

Further evidence of bowing is afforded by the attitude of the
Tertiary strata themselves, more highly inclined in the case of
the older Tertiary, less highly inclined in the case of the younger
Tertiary. It is noteworthy that the gradient of the present val-
ley floor is distinctly less than that of the least highly inclined
strata. This is true even where aggradation is now just able to
continue, as near the nodal point of the valley, above Aplao,
where cutting ceases and aggradation begins. (See the Aplao
Quadrangle for change of function on the part of the stream
a half mile above Cosos). Such a progressive steepening of

232 THE ANDES OF SOUTHERN PERU

gradients in the direction of the oldest deposits, shows very
clearly a corresponding progression in the growth of the Andes
at intervals throughout the Tertiary.

Thus we have aggradation in the Tertiary at the foot of the
growing Andes ; aggradation in the Pliocene or early Pleistocene
on the floor of a deep valley cut in earlier deposits; aggradation
in the glacial epoch; and aggradation now in progress. Basin
deposits within the borders of the Peruvian Andes are relatively
rare. The profound erosion implied by the development, first of
a mature topography across this great Cordillera, and second of
many deep canyons, calls for deposition on an equally great scale
on the mountain borders. The deposits of the western border are
a mile thick, but they are confined to a narrow zone between the
Coast Range and the Cordillera. Whatever material is swept be-
yond the immediate coast is deposited in deep ocean water, for
the bottom falls off rapidly. The deposits of the eastern border
of the Andes are carried far out over the Amazon lowland. Those
of earlier geologic periods were largely confined to the mountain
border, where they are now upturned to form the front range of
the Andes. The Tertiary deposits of the eastern border are less
restricted, though they appear to have gathered chiefly in a belt
from fifty to one hundred miles wide.

The deposits of the western border were laid down by short
streams rising on a divide only 100 to 200 miles from the Pacific.
Furthermore, they drain the dry leeward slopes of the Andes.
The deposits of the wet eastern border were made by far larger
streams that carry the waste of nearly the whole Cordillera.
Their shoaling effect upon the Amazon depression must have been
a large factor in its steady growth from an inland sea to a river
lowland.

CHAPTER XV
PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT

GENERAL, FEATURES

In the preceding chapter we employed geologic facts in the
determination of the age of the principal topographic forms.
These facts require further discussion in connection with their
closest physiographic allies if we wish to show how the topog-
raphy of today originated. There are many topographic details
that have a fundamental relation to structure; indeed, without a
somewhat detailed knowledge of geology only the broader and
more general features of the landscape can be interpreted. Li this
chapter we shall therefore refer not to the scenic features as in a
purely topographic description, but to the rock structure and the
fossils. A complete and technical geologic discussion is not de-
sirable, first, because it should be based upon much more detailed
geologic field work, and second because after all our main pur-
pose is not to discuss the geologic features per se, but the physio-
graphic background which the geologic facts afford. I make this
preliminary observation partly to indicate the point of view and
partly to emphasize the necessity, in a broad, geographic study,
for the reconstruction of the landscapes of the past.

The two dominating ranges of the Peruvian Andes, called the
Maritime Cordillera and the Cordillera Vilcapampa, are com-
posed of igneous rock — the one volcanic lava, the other intrusive [)
granite. The chief rock belts of the Andes of southern Peru are
shown in Fig. 157. The Maritime Cordillera is bordered on the
west by Tertiary strata that rest unconformably upon Palaeozoic
quartzites. It is bordered on the east by Cretaceous limestones
that grade downward into sandstones, shales, and basal conglom-
erates. At some places the Cretaceous deposits rest upon old
schists, at others upon Carboniferous limestones and related/

233 '

234 THE ANDES OF SOUTHERN PERU

strata, upon small granite intrusives and upon old and greatly
altered volcanic rock.

/ The Cordillera Vilcapampa lias an axis of granitic rock which
^was thrust upward through schists that now border it on the west
/ and slates that now border it on the east. The slate series forms
a broad belt which terminates near the eastern border of the
Andes, where the mountains break down abruptly to the river
plains of the Amazon Basin. The immediate border on the east
is formed of vertical Carboniferous limestones. The narrow foot-
hill belt is composed of Tertiary sandstones that grade into loose
sands and conglomerates. The inclined Tertiary strata were lev-
eled by erosion and in part overlain by coarse and now dissected
river gravels, probably of Pleistocene age. Well east of the main
border are low ranges that have never been described. They
could not be reached by the present expedition on account of lack
of time. On the extreme western border of that portion of the
Peruvian Andes herein described, there is a second distinct border
chain, the Coast Range. It is composed of granite and once had
considerable relief, but erosion has reduced its former bold forms
V to gentle slopes and graded profiles.

The continued and extreme growth of the Andes in later geo-
logic periods has greatly favored structural and physiographic
studies. Successive uplifts have raised earlier deposits once
buried on the mountain flanks and erosion has opened canyons on
whose walls and floors are the clearly exposed records of the past.
In addition there have been igneous intrusions of great extent
that have thrust aside and upturned the invaded strata exposing
still I'll 1-1 lnT the intoninl structures of the mountains. From sec-
tions tlms r(,'vealed it is possible to outline the chief events in the
liistory of the Peruvian Andes, though the outline is still neces-
arily broad and general because based on rapid reconnaissance.
However, it shows cjcaily lli;il the landscape oi" Ihc present repre-
sents but ;i teiiipoi'jiry stage in the cxoliillon ol" a great, nionntain
bolt. At the dawn of geologic history there were chains oC nioun-
^ tains where the Andes now stand. They were swept away and
' even their roots deeply submerged under invading seas. Re-

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 235

Fig. 157 — Outline sketcli showiiig the
principal rock belts of Peru along the
seventy-third meridian. They are: 1,
Pleistocene and Recent gravels and sands,
the former partly indurated and slightly
deformed, with the degree of deformation
increasing toward the mountain border
(south). 2, Tertiary sandstones, inclined
from 15° to 30° toward the north and
unconformably overlain by Pleistocene
gravels. 3, fossil-bearing Carboniferous
limestones with vertical dip. Jf, non-fos-
siliferous slates, shales, and slaty schists
(Silurian) with great variation in degree
of induration and in type of structure.
South of the parallel of 1.3° is a belt of
Carboniferous limestones and sandstones
bordering (5) the granite axis of the
Cordillera Vilcapampa. For its structural
relations to the Cordillera see Figs. 141 and
142. 6, old and greatly disturbed volcanic
agglomerates, tuffs and porphyries, and
quartzitic schists and granite-gneiss. 7,
principally Carboniferous limestones north
of the axis of the Central Ranges and
Cretaceous limestones south of it. Local
granite batholiths in the axis of the Central
Ranges. 8, quartzites and slates predomi-
nating with thin limestones locally. South
of S is a belt of shale, sandstone, and lime-
stone with a basement quartzite appearing
on the valley floors. 9, a portion of the
great volcanic field of the Central Andes
and characteristically developed in the
Western or Maritime Cordillera, through-
out northern Chile, western Bolivia, and
Peru. At Cotahuasi (see also Fig. 20)
Cretaceous limestones appear beneath the
lavas. 10, Tertiary sandstones of the
coastal desert with a basement of old vol-
canies and quartzites appearing on the
valley walls. The valley floor is aggraded
with Pleistocene and Recent alluvium. 11,
granite-gneiss of the Coast Range. 12, late
Tertiary or Pleistocene sands and gravels
deposited on broad coastal terraces. For
rock structure and character see the other
figures in this chapter. For a brief desig-
nation of index fossils and related forms
see Appendix B. For the names of the
drainage lines and the locations of the
principal towns see Figs. 20 and 204.

+- -^

+ -i
+ +

+ + -t-
•t- + +

+ + + •(- + ■1-+ +-I-

^"^^'TtJ- ^ ^ ^

+ + >-t-4^C ■*■ + -^■

236 THE ANDES OF SOUTHERN PERU

peated uplifts of the earth's crust reformed the ancient chains or
created new ones out of the rock waste derived from them. Each
new set of forms, therefore, exhibits some features transmitted
from the past. Indeed, the landscape of today is like the human
race — inheriting much of its character from past generations.
For this reason the philosophical study of topographic forms re-
quires at least a broad knowledge of related geologic structures.

SCHISTS AND SILURIAN SLATES ^

The oldest series of rocks along the seventy-third meridian of
Peru extends eastward from the Vilcapampa batholith nearly to
the border of the Cordillera, Fig. 157. It consists of (1) a great
mass of slates and shales with remarkable uniformity of composi-
tion and structure over great areas, and (2) older schists and
siliceous members in restricted belts. They are every^vhere thor-
oughly jointed; near the batholith they are also mineralized and
altered from their original condition; in a few places they have
been intruded with dikes and other form of igneous rock.

The slates and shales underlie kno\vn Carboniferous strata on
their eastern border and appear to be a physical continuation of
the fossiliferous slates of Bolivia; hence they are provisionally
referred to the Silurian, though they may possibly be Devonian.
Certainly the known Devonian exceeds in extent the known
Silurian in the Central Andes but its lithological character is
generally quite unlike the character of the slates here referred to
the Silurian. The schists are of great but unknown age. They
arc unconformably overlain by kno\vn Carboniferous at Pnquinra
in the Vilcapampa Valley (Fig. 158), and near Chuquibambilla on
the opposite side of the Cordillera Vilcapampa. The deeply
wcalhered fissile mica schists east of Pasaje (see Appendix C for
ill! locations) are also unconformably overlain by conglomerate
and sandstone of Carboniforoiis nge. While the schists vary con-
siderably in lithological appearance and also in structure, they are
everywliere the lowest rocks in the series and may with confidence

'For a list of tlio foBsilH tlml forni tlic luiHin of tlic nf,'c drtiTiiiiiKil ions in this
cliaptcr see Appendix B.

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 237

be referred to the early Palaeozoic, while some of them may date
from the Proteriozoic.

The Silurian beds are composed of shale, sandstone, shaly
sandstone, limestone, and slate with some slaty schist, among
which the shales are predominent and the limestones least impor-
tant. Near their contact with the granite the slate series is com-
posed of alternating beds of sandstone and shale arranged in
beds from one to three feet thick. At Santa Ana they become

Porphyry

Fig. 158 — Geologic sketch map of tu^ lower Urubai.ibu Valley. A single traverse
was made along the valley, hence the boundaries are not accurate in detail. They were
sketched in along a few lateral traverses and also inferred from the topography.
The country rock is schist and the granite intruded in it is an arm of the main
granite mass that constitutes the axis of the Cordillera Vilcapampa. The structure
and to some degree the extent of the sandstone on the left are represented in Figs.
141 and 142.

more fissile and slaty in character and in several places are quar-
ried and used for roofing. At Eosalina they consist of almost
uniform beds of shale so soft and so minutely and thoroughly
jointed as to weather easily. Under prolonged erosion they have,
therefore, given rise to a well-rounded and soft-featured land-
scape. Farther down the Urubamba Valley they again take on
the character of alternating beds of sandstone and shale from a
few feet to fifteen and more feet thick. In places the metamor-
phism of the series has been carried further — the shales have be-
come slates and the sandstones have been altered to extremely re-
sistant quartzites. The result is again clearly shown in the topog-
raphy of the valley wall which becomes bold, inclosing the river

238 THE ANDES OF SOUTHERN PERU

in narrow "pongos" or canyons filled with huge bowlders and
dangerous rapids. The hills become mountains, ledges appear,
and even the hea\'y forest cover fails to smooth out the natural
ruggedness of the landscape.

It is only upon their eastern border that the Silurian series
includes calcareous beds, and all of these lie within a few thou-
sand yards of the contact with the Carboniferous limestones and
shales. At first they are thin paper-like layers; nearer the top
they are a few inches wide and finally attain a thickness of ten
or twelve feet. The available limestone outcrops were rigor-
ously examined for fossils but none were found, although they
are lavishly distributed throughout the younger Carboniferous
beds just above them. It is also remarkable that though the
Silurian age of these bods is reasonably inferred they are not
separated from the Carboniferous by an unconformity, at least we
could find none in this locality. The later beds disconformably
overlie the earlier beds, although the sharp differences in lithology
and fossils make it easy to locate the line of separation. The
limestone beds of the Silurian series are extremely compact and
unfossiliferous. At least in this region those of Carboniferous
age are friable and the fossils varied and abundant. The Silurian
beds are everjrwhere strongly inclined and throughout the eastern
half or third of their outcrop in the Urubamba Valley they are
nearly vertical.

In view of the enormous thickness of the repeated layers of
shale aud sandstone this series is of great interest. Added im-
portance attaches to their occurrence in a long belt from the
eastern edge of the Bolivian highlands northward through Peru
and possibly farther. From the fact that their disturbance has
been on broad lines over wide areas with extreme metamorphism,
they are to be separated IVoiii llie oldei- mica-schists and the
cninipled clilorile schists of Puquiura and Pasaje. I*'iii-llier rea-
sons for this distinction lie in their lithologic difference; and, to
a more important degree, in tlie strong unconformity between the
Carboniferous and th<' schists in contrast to tlie disconformable
relations shown hetwceii the Carboniferous and Silurian fifty

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 239

miles away at Pongo de Mainique. The mashing and crumpling
that the schists have experienced at Puquiura is so intense, that
were they a part of the Silurian series the latter should exhibit
at least a slight unconformity in relation to the Carboniferous
limestones deposited upon them.

If our interpretation of the relation of the schists to the slates
and shales be correct, we should have a mountain-making period
introduced in pre-Silurian time, affecting the accumulated sedi-
ments and bringing about their metamorphism and crumpling on
a large scale. From the mountains and uplands thus created on
the schists, sediments were washed into adjacent waters and ac-
cumulated as even-bedded and extensive sheets of sands and muds
(the present slates, shales, quartzites, etc.). Nowhere do the sedi-
ments of the slate series show a conglomeratic phase; they are
remarkably well-sorted and consist of material disposed with
great regularity. Though they are coarsest at the bottom the
lower beds do not show cross-bedding, ripple marking, or other
signs of shallow-water conditions. Toward the upper part of the
series these features, especially the ripple-marking, make their
appearance. During the deposition of the last third of the series,
and again just before the deposition of the limestone, the beds
took on a predominantly arenaceous character associated with
ripple marks and cross-bedding characteristic of shallow-water
deposits.

In the persistence of arenaceous sediments throughout the
series and the distribution of the ripple marks through the upper
third of the beds, we have a clear indication that the degree of
shallowness was sufficient to bring the bottom on which the sedi-
ments accumulated into the zone of current action and possibly
wave action. It is also w^orth considering whether the currents
involved were not of similar origin to those now a part of the
great counter-clockwise movements in the southern seas. If so,
their action would be peculiarly effective in the wide distribution
of the sediment derived from a land mass on the eastern edge of
a continental coast, since they would spread out the material to
a greater and greater degree as they flowed into more southerly

240 THE ANDES OF SOUTHERN PERU

latitudes. Among geologic agents a broad ocean current of
relatively uniform flow would produce the most uniform effects
throughout a geologic period, in which many thousand feet of
clastic sediments were being accumulated. A powerful ocean cur-
rent would also work on flats (in contrast to the gradient re-
quired by near-shore processes), and at the same time be of such
deep and steady flow as to result in neither ripple marks nor cross-
bedding.

The increasing volume of shallow- water sediments of uniform
character near the end of the Silurian, indicates great crustal
stability at a level which brought about neither a marked gain
nor loss of material to the region. At any rate we have here no
Devonian sediments, a characteristic shared by almost all the
great sedimentary formations of Peru. At the beginning of the
Carboniferous the water deepened, and great heavy-bedded lime-
stones appear with only thin shale partings through a vertical dis-
tance of several hundreds of feet. The enormous volume of
Silurian sediments indicates the deep and prolonged erosion of
the land masses then existing, a conclusion further supported (1)
by the extensive development of the Silurian throughout Bolivia
as well as Peru, (2) by the entire absence of coarse material
whether at the top or bottom of the section, and (3) by the very
limited extent of older rock now exposed even after repeated and
irregular uplift and deep dissection. Indeed, from the latter very
striking fact, it may be reasonably argued that in a general way
the relief of the country was reduced to sea level at the close of
the Silurian. Over the perfected grades of that time there would
then be afforded an opportunity for the effective transportation
of waste to the extreme limits of the land.

Further evidence of the great reduction of surface during the
Silurian niid Devonian is supplied by the extensive development
of tlic Carboniferous strata. Their outcrops are now scattered
across the higlier portions of the Andean Cordillera and are pre-
vailingly calcareous in their upper portions. Upon the eastern
border of the Silurian they indicate marine conditions from the
opening of the period, but at Pasajc in the Apurimac Valley they

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 24.1

are marked by heavy beds of basal conglomerate and sandstone,
and an abundance of ripple marking and other features associated
with shallow-water and possibly near-shore conditions.

CAKBONIFEROUS

Carboniferous strata are distributed along the seventy-third
meridian and rival in extent the volcanic material that forms the
^vestern border of the Andes. They range in character from
basal conglomerates, sandstones, and shales of limited develop-
ment, to enormous beds of extremely resistant blue limestone, in
general well supplied with fossils. On the eastern border of the

FRONT RANGE

Fig. 159 — Topographic and structural section at the northeastern border of the
Peruvian Andes. The slates are probably Silurian, the fossiliferous limestones are
known Carboniferous, and the sandstones are Tertiary grading up to Pleistocene.

Andes they are abruptly terminated by a great fault, the continua-
tion northward of the marginal fault recognized in eastern
Bolivia by Minchin^ and farther north by the writer.^ Coarse
red sandstones with conglomeratic phase abut sharply and with
moderate inclination against almost vertical sandstones and lime-
stones of Carboniferous age. The break between the vertical lime-
stones and the gently inclined sandstones is marked by a promi-
nent scarp nearly four thousand feet high (Fig. 159), and the
limestone itself forms a high ridge through which the Urubamba
has cut a narrow gateway, the celebrated Pongo de Mainique.

At Pasaje, on the western side of the Apurimac, the Carbonifer-
ous again appears resting upon the old schists described on p. 236.
It is steeply upturned, in places vertical, is highly conglomeratic,
and in a belt a half-mile wide it forms true badlands topography.

* Eastern Bolivia and the Gran Chaco, Proc. Royal Geogr. Soc, Vol. 3, 1881, pp.
401-420.

• The Physiography of the Central Andes, Am. Journ. Sci., Vol. 28, 1909, p. 395.

242

THE ANDES OF SOUTHERN PERU

g^e^

LIMESTONE \

^ ><imestohe/

It is succeeded by evenly bedded sandstones of fine and coarse
composition in alternate beds, then follow shales and sandstones
and finally the enormous beds of limestone that characterize the
series. The structure is on the whole relatively simple in this
region, the character and attitude of the beds indicating their ac-
cumulation in a nearly horizontal position. Since the basal con-
glomerate contains only pebbles and stones derived from the sub-
jacent schists and does not contain granites like those in the Cor-
dillera Vilcapampa batholith on the east it is concluded that the

batholithic invasion was ac-
companied by the compression
and tilting of the Carbonifer-
ous beds and that the batholith
itself is post-Carboniferous.
From the ridge summits above
Huascatay and in the deep
valleys thereabouts the Car-
boniferous strata may be seen
to extend far toward the west,
and also to have great extent
north and south. Because of
their dissected, bare, and, therefore, well-exposed condition they
present exceptional opportunities for the study of Carboniferous
geology in central Peru.

Carboniferous strata again appear at Puquiura, Vilcapampa,
and Pampaconas. They are sharply upturned against the Vilca-
pampa batliolith and associated volcanic material, chiefly basalt,
porphyry, and various tuffs and related breccias. The Carbonifer-
ous beds are here more arenaceous, consisting cliiofly of alternat-
ing beds of sandstone and shale. The lowermost ])eds, as at
Pongo de IMainique, are dominantly marine, fossiliferous lime-
stone beds having a tliickness estimated to be over two miles.

From TTiiMScntay westward and southward the Carboniferous
is in part displaced by secondary balholiths of grani<(\ in part
cut off or crowded aside by igneous intrusions of later date, and
in still larger part Ijuricd undor great masses of Tertiary volcanic

M s

Fig. IGO — The deformative eflfeets of
the granite intrusion of the Cordillera
Vilcapampa are here shoAvn as trans-
mitted through ancient schists to the
overlying conglomerates, sandstones, and
limestones of Carboniferous agi>, in the
Apurimac Valley at Pasaje.

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 243

Fig. IGl — Types of deformation north
of Lambrama near Sotospampa. A
dark basaltic rock has invaded both
granite-gneiss and slate. Sills and dikes
occur in great numbers. The topographic
depression in the profile is the Lambrama
Valley. See the Lambrama Quadrangle.

materiaL Nevertheless, it remains the dominating rock type over
the whole stretch of country from Huascatay to Huancarama. In
the northwestern part of the Abancay sheet its effect on the land-
scape may be observed in the
knife-like ridge extending from
west to east just above Hu-
ambo. Above Chuquibambilla
it again outcrops, resting upon
a thick resistant quartzite of
unknown age. Fig. 162. It is
strongly developed about
Huadquirca and Antabamba
and, still associated with a
quartzite floor, it finally disap-
pears under the lavas of the

great volcanic field on the western border of the Andes. Figs. 141
and 142 show its relation to the invading granite batholiths and
Fig. 162 shows further structural features as developed about
Antabamba where the great volcanic field of the Maritime Cordil-
lera begins.

Both the enormous thickness of the Carboniferous limestone
series and the absence of clastic members over great areas in the

upper portion of the series
prove the widespread extent of
the Carboniferous seas and their
former occurrence in large in-
terlimestone tracts from which
they have since been eroded.
At Puquiura they extend far
over the schist, in fact almost
completely conceal it ; at Pasaje
they formerly covered the mica-
schists extensively, their ero-
sion in both cases being conditioned by the pronounced uplift and
marginal deformation which accompanied the development of the
Vilcapampa batholith.

Fig. 162 — Sketch sections at Anta-
bamba to show (a) deformed limestones
on the upper edge of the geologic map,
Fig. 163 A; and (b) the structural rela-
tions of limestone and quartzite. See
also Fig. 163.

244

THE ANDES OF SOUTHERN PERU

C D

Fig. 163 — Geologic sketch section to
show the relation of the volcanic flows
of Fig. 1G4 to the sandstones and quart-
zites beneath.

The degree of deformation of the Carboniferous sediments
varies between simple uplift through moderate folding and com-
plex disturbances resulting in nearly vertical attitudes. The sim-
plest structures are represented at Pasaje, where the uplift of the

intruded schists, marginal to
the Vilcapampa batholith, has
produced an enormous mono-
clinal fold exposing the entire
section from basal conglomer-
ates and sandstones to the
thickest limestone. Above Chu-
quibambilla the limestones have
been uplifted and very gently folded by the invasion of granite as-
sociated with the main batholith and several satellitic batholiths of
limited extent. A higher degree of complexity is shoAvn at Pampa-
conas (Fig. 141), where the main monoclinal fold is traversed al-
most at right angles by secondary folds of great amplitude. The
limestones are there carried to the limit of the winter snows almost
at the summit of the Cordillera. The crest of each secondary anti-
cline rises to form a group of conspicuous peaks and tabular
ridges. Higher in the section, as at Puquiura, the sandstones are
thrown into a series of huge anticlines and synclines, apparently
by the marginal compression brought about at the time of the in-
trusion of the granite core of the range. At Pongo de Mainique
the whole of the visible Carboniferous is practically vertical, and
is cut off by a great fault marking the abrupt eastern border of
the Cordillera.

It is noteworthy that the farther east the Carboniferous ex-
tends the more dominantly marine it becomes, though marine beds
of great thickness constitute a large part of tlio series in what-
ever location. From Huascatay westward the limestones become
more and more argillaceous, and finally give way altogothor to an
enormous thickness of shales, sandstones, and thin conglomerates.
These were observed to extend with strong inclination westward
out of the region studied and into and under the volcanoes crown-
ing the western bord<'r of the Cordillera. Along the line of

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 245

traverse opportunity was not afforded for further study of this
aspect of the series, since our route led generally along the strike
rather than along the dip of the beds. It is interesting to note,
however, that these observations as to the increasing amounts of
clastic material in a westward direction were afterwards con-
firmed by Senor Jose Bravo, the Director of the Bureau of Mines
at Lima, who had found Carboniferous land plants in shales at
Pacasmayo, the only fossils of
their kind found in Peru. For-
merly it had been supposed that
non-marine Carboniferous was
not represented in Peru. From
the varied nature of the flora,
the great thickness of the shales
in which the specimens were col-
lected, and the fact that the
dominantly marine Carbonifer-
ous elsewhere in Peru is of
great extent, it is concluded that
the land upon which the plants
grew had a considerable area
and probably extended far west
of the present coast line. Since
its emergence it has passed
through several orogenic move-
ments. These have resulted in
the uplift of the marine portion
of the Carboniferous, while the
terrestrial deposits seem to have
all but disappeared in the down-sunken blocks of the ocean floor,
west of the great fault developed along the margin of the Cordil-
lera. The following figures are graphic representations of this
hypothesis.

The wide distribution of the Carboniferous sediments and
especially the limestones, together with the uniformity of the fos-
sil faunas, makes it certain that the sea extended entirely across

A B

Fig. 164 — Geologic sketch map and
section, Antabamba region. The Anta-
bamba River has cut through almost the
entire series of bedded strata.

246

THE ANDES OF SOUTHERN PERU

c a.
8 ^

to 01

bo g

5 -^ ^ c

03 rG

i3 ■-= c

C3 t) -; t-i

+3 c .s "^

JS ^ DD 'O

P-O

> ^^

-tJ

;z!

'7-;

B
Of

S
in

-€

' — '

-iJ

""^

►•

• "

•«->

'-5

-»j

-2

■5

_eo

0)
^3
1-

- ^ "S i g

•«o

"rt

f>H

C
01

-u

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 247

the region now occupied by the Andes. However, from the rela-
tion of the Carboniferous to the basal schists, and the most con-
servative extension of the known Carboniferous, it may be in-
ferred that the Carboniferous sea did not completely cover the
entire area but was broken here and there by island masses in the
form of an elongated archipelago. The presence of land plants
in the Carboniferous of Pisco warrants the conclusion that a sec-
ond island mass, possibly an island chain parallel to the first, ex-
tended along and west of the present shore.

(S3 Alluvium ^limestDneHHSandsfone s Shale ^Volcanic

CRETACEOUS

The Cretaceous formations are of very limited extent in the
belt of country under consideration, in spite of their generally
wide distribution in Peru. They
are exposed distinctly only on
the western border of the Cor-
dillera and in special relations.
In the gorge of Cotahuasi, over
seven thousand feet deep, about
two thousand feet of Cretaceous
limestones are exposed. The
series includes only a very re-
sistant blue limestone and ter-
minates abruptly along a well-
marked and highly irregular
erosion surface covered by al-
most a mile of volcanic ma-
terial, chiefly lava flows. The
character of the bottom of the
section is likewise unknown,
since it lies apparently far be-
low the present level of ero-
sion.

The Cretaceous limestones of the Cotahuasi Canyon are every-
where greatly and irre.gularly disturbed. Typical conditions are
represented in the maps and sections. Figs. 166 and 167. They are

Fig. 16G — Geologic sketch map and
cross-section in the Cotahuasi Canyon at
Cotahuasi. With a slight gap this figure
continues Fig. 167 to the left. The sec-
tion represents a spur of the irain plateau
about 1,500 feet high in the center of the
map.

248

THE ANDES OF SOUTHERN PERU

f::-- vl l^llu'lui'' II I III IhickConqlandSandstiine p^^ UniKtone g§^ Volcanic .

penetrated and tilted by igneous masses, apparently the feeders
of the great lava sheets that form the western summit of the
Cordillera. From the restricted development of the limestones
along a western border zone it might be inferred that they rep-
resent a very limited marine in-
vasion. It is certainly clear that
great deformative movements
were in progress from at least
late Palaeozoic time since all the
Palaeozoic deposits are broken
abruptly down in this direction,
and, except for such isolated oc-
currences as the land Carbonif-
erous at Pacasmayo, are not
found anywhere in the coastal
region today. The Cretaceous
is not only limited within a
relatively narrow shore zone,
but also, like the Palaeozoic, it
is broken down toward the west,
not reappearing from beneath
the Tertiary cover of the desert
region or upon the granite-gneisses that form the foundation for
all the known sedimentary strata of the immediate coast.

From these considerations I tliink we have a strong suggestion
of the geologic date assignable to the development of the great
fault that is the most strongly marked structural and physio-
graphic feature of the west coast of South America. Since the
development of this fault is so intimately related to the origin of
the Pacific Ocean basin its study is of special importance. The
points of chief interest may be summarized as follows :

(1) The character of the land Carboniferous implies a much
greater extent of the land than is now viRil)lo.

(2) The progressive coarsening of the Carboniferous deposits
westward and their land derivation, together with the great thick-
ness of the series, point to an elevated land mass in process of

Fig. 167 — Geologic sketch map and
cro3--8ection in the Cotahuasi Canyon at
Taurisma, above Cotaliuasi. The relati ns
of limestone and lava flows in the center
of the map and on a spur top near the
canyon floor. Thousands of feet of "ava
extend upward from the flows that cap
the limestone.

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 249

erosion west of the series as a whole, that is west of the present
coast.

(3) The restricted development of the Cretaceous seas upon
the western border of the Carboniferous, and the still more re-
stricted development of the Tertiary deposits between the moun-
tains and the present coast, point to increasing definition of the
submarine scarp through the Mesozoic and the Tertiary.

(4) The Tertiary deposits are all clearly derived from the
present mountains and have been washed seaward do^\^l slopes
with geographic relations approximately like those of the present.

(5) From the great width, deep dissection, and subsequent

Clays and sands.

Red sandstone and shale.

Gray and yellow sandstone and shale.

Basal sandstone.
Volcanic agglomerate.
Volcanic flows.

Slaty schist.
Granite.

Fig. 168 — Composite structure section representing the succession of rocks in the
Urubamba Valley from Urubamba to Torontoy.

burial of the Tertiary terraces of the coast, it is clear that the
greater part of the adjustment of the crust to which the bordering
ocean basin is due was accomplished at least by mid-Tertiary
time.

Aside from the fossiliferous limestones of kno^vn Cretaceous
age there have been referred to the Cretaceous certain red sand-
stones and shales marked, especially in the central portions of the
Cordillera, by the presence of large amounts of salt and gypsum.
These beds were at first considered Permian, but Steinmann has
since found at Potosi related and similar formations with Creta-
ceous fossils. In this connection it is also necessary to add that
the great red sandstone series forming the eastern border of the
Andes in Bolivia is of uncertain age and has likewise been re-

250 THE ANDES OF SOUTHERN PERU

ferred to the Cretaceous, though the matter of its age has not yet
been definitely determined. In 1913 I found it appearing in north-
western Argentina in the Calchaqui Valley in a relation to the
main Andean mass, similar to that displayed farther north. It
contains fossils and its age was, therefore, readily determinable
there.*

In the Peruvian field the red beds of questionable age were not
examined in sufficient detail to make possible a definite age de-
termination. They occur in a great and only moderately disturbed
series in the Anta basin north of Cuzco, but are there not fos-
siliferous. The northeastern side of the hill back of Puqura (of
the Anta basin: to be distinguished from Puquiura in the Vilca-
bamba Valley) is composed largely of rocks of this class. In a
few places their calcareous members have been weathered out in
such a manner as to show karst topography. Where they occur
on the well-drained brow of a bluff the caves are used in place
of houses by Indian farmers. The large and strikingly beautiful
Lake Huaipo, ten miles north of Anta, and several smaller, neigh-
boring lakes, appear to have originated in solution depressions
formed in these beds.

The structural relation of the red sandstone series to the older
rocks is well displayed about half-way between Urubamba and
Ollantaytambo in the deep Urubamba Valley. The basal rocks are
slaty schist and granite succeeded by agglomerates and basalt por-
phyries upon whose eroded surfaces (Fig. 169) are gray to yel-
low cross-bedded sandstones. Within a few hundred feet of the
unconformity gypsum deposits begin to appear and increase in
number to such an extent that the resulting soil is in places rcn-
dorcd worthless. Copper-stained bands are also common near the
bottom of the series, but these are confined to the lower beds.
Higher up in the section, for example, just above the gorge between
Urubamba and Ollantaytambo, even-bedded sandstones occur
whose most prominent characteristic is the regular succession of

* Reo pnpor by IT. S. Pnlmor, my nHHiHtant on tlin Expedition to the rontrnl Anrloa,
1913, entitle*!: OcoloRicnl Notes on the Ancha of Northwestern Argentina, Ani. .foiirn.
Sci., Vol. 38, ini4, pp. 300 330.

xJf'^J!:

J -,'3* •»!».«*«1»» «

X.-

•\-M

Fig. 169.

Fig. 170.

Fig. 169 — The line of unconformity between the igneous basement rocks (agglom-
erates at this point) and the quartzites and sandstones of the Urubamba Valley,
between the town of Urubamba and OUantaytambo.

Fig. 170 — The inclined lower and horizontal upper sandstone on the southeastern
wall of the Majes Valley at Hacienda Cantas. The section is a half-mile high.

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 251

coarse and fine sandstone beds. Such alternations of character in
sedimentary rocks are commonly marked by alternating shales
and sandstones, but in this locality shales are practically absent.
Toward the top of the section gypsum deposits again appear first
as beds and later, as in the case of the hill-slope on the southern
shore of Lake Huaipo, as veins and irregular masses of gypsum.
The top of the deformed Cretaceous (?) is eroded and again cov-
ered unconformably by practically flat-lying Tertiary deposits.

TERTIARY

The Tertiary deposits of the region under discussion are
limited to three regions: (1) the extreme eastern border of the
main Cordillera, (2) intermontane basins, the largest and most
important of which are (a) the Cuzco basin and (b) the Titicaca-
Poopo basin on the Peruvian-Bolivian frontier, and (3) in the
west-coast desert and in places upon the huge terraces that form
a striking feature of the topography of the coast of Peru.

It has already been pointed out that the eastern border of the
Cordillera is marked by a fault of great but undetermined throw,
whose topographic importance may be estimated from the fact
that even after prolonged erosion it stands nearly four thousand
feet high. Cross-bedded and ripple-marked features and small
lenses of conglomerate are common. The beds now dip at an
angle approximately 20° to 50° northward at the base of the scarp,
but have decreasing dip as they extend farther north and east.
It is noteworthy that the deposits become distinctly conglomeratic
as flatter dips are attained, and that there seems to have been a
steady accumulation of detrital material from the mountains for
a long period, since the deposits pass in unbroken succession from
the highly indurated and massive beds of the mountain base to
loose conglomerates that now weather down much like an ordi-
nary gravel bank. In a few places just below the mouth of the
Ticumpinea, logs about six inches in diameter were observed
embeded in the deposits, but these belong distinctly to the upper
horizons.

The border deposits, though they vary in dip from nearly flat

252 THE ANDES OF SOUTHERN PERU

to 50°, are everj^vvhere somewhat inclined and now lie up to sev-
eral hundred feet above the level of the Urubamba River. Their
upper surface is moderately dissected, the degree of dissection be-
ing most pronounced where the dips are steepest and the height
greatest. In fact, the attitude of the deposits and their progres-
sive change in character point toward, if they do not actually
prove, the steady and progressive character of the beds first de-
posited and their erosion and redeposition in beds now higher in
the series.

Upon the eroded upper surfaces of the inclined border de-
posits, gravel beds have been laid which, from evidence discussed
in a later paragraph, are without doubt referable to the Pleis-
tocene. These in turn are now dissected. They do not extend to
the highest summits of the deformed beds but are confined, so
far as observations have gone, to elevations about one hundred
feet above the river. From the evidence that the overlying hori-
zontal beds are Pleistocene, the thick, inclined beds are referred
to Tertiary age, though they are nowhere fossiliferous.

Observations along the Urubamba River were extended as far
northward as the mouth of the Timpia, one of the larger tribu-
taries. Upon returning from this point by land a wide view of
the country was gained from the four-thousand-foot ridge of
vertical Carboniferous limestone, in which it appeared that low
and irregular strike ridges continue the features of the Tertiary
displayed along the mountain front far northward as well as east-
ward, to a point wliere the higher ridges and low mountains of
older rock again appear — the last outliers of the Andean system
in Peru. Unfortunately time enough was not available for an ex-
tension of the trip to these localities whose geologic characters
still remain entirely unknown. From the topographic aspects of
the country, it is, however, reasonably certain that the whole in-
tervening depression between these outlying ranges and the
border of the main Cordillera, is filled with inclined and now dis-
sected and partly covered Tertiary strata. The elevation of the
upper surface does not, however, remain the same; it appears to
decrease steadily and the youngest Tertiary strata disappear

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 253

from view below the sediments of either the Pleistocene or the
present river gravels. In the more central parts of the depres-
sion occupied by the Urubamba Valley, only knobs or ridges pro-
ject here and there above the general level.

The Coastal Tertiary

The Tertiary deposits of the Peruvian desert region southwest
of the Andes have many special features related to coastal de-
formation, changes of climate, and great Andean uplifts. They
lie between the west coast of Peru at Camana and the high, lava-
covered country that forms the western border of the Andes and
in places are over a mile thick. They are non-fossiliferous, cross-
bedded, ripple-marked, and have abundant lenses of conglomerate
of all sizes. The beds rest upon an irregular floor developed upon
a varied mass of rocks. In some places the basement consists of
old strata, strongly deformed and eroded. In other places it con-
sists of a granite allied in character and probably in origin with
the old granite-gneiss of the Coast Range toward the west. Else-
where the rock is lava, evidently the earliest in the great series
of volcanic flows that form this portion of the Andes.

The deposits on the western border of the Andes are excel-
lently exposed in the Majes Valley, one of the most famous in
Peru, though its fame rests rather upon the excellence and abun-
dance of its vineyards and wines than its splendid geologic sec-
tions. Its head lies near the base of the snow-capped peaks of
Coropuna; its mouth is at Camana on the Pacific, a hundred miles
north of Mollendo. It is both narrow and deep; one may ride
across its floor anywhere in a half hour. In places it is a narrow
canyon. Above Cantas it is sunk nearly a mile below the level of
the desert upland through which it flows. Along its borders are
exposed basal granites, old sedimentaries, and lavas ; inter-bedded
with it are other lavas that lie near the base of the great volcanic
series; through it still project the old granites of the Coast
Range; and upon it have been accumulated additional volcanic
rocks, wind-blo^\Ti deposits, and, finally, coarse wash formed dur-
ing the glacial period. From both the variety of the formations,

254

THE ANDES OF SOUTHERN PERU

the small amount of marginal dissection, and the excellent expo-
sures made possible by the deep erosion and desert climate, the
Majes Valley is one of the most profitable places in Peru for
physiographic and geologic study.

The most complete succession of strata (Tertiary) occurs just
below Cantas on the trail to Jaguey (Fig. 171). Upon a floor of
granite-gneiss, and alternating beds of quartzite and shale belong-

COASTAL DESERT

MARITIME CORDILLERA

Fig. 171 — Generalized sketch section to show the structural relations of the Mari-
time Cordillera, the desert pampas, and the Coast Eange.

ing to an older series, are deposited heavy beds of red sandstone
with many conglomerate lenses. The sandstone strata are meas-
urably deformed and their upper surfaces moderately dissected.
Upon them have been deposited unconformably a thicker series
of deposits, conglomerates, sandstones, and finer wind-blown ma-
terial. The basal conglomerate is very coarse— much like beach
material in both structure and composition, and similar to that
along and south of the present coast at Camana. Higher in the
section the material is prevailingly sandy and is deposited in
regular beds from a few inches to a few feet in thickness. Near
the top of the section are a few hundred feet of strata chiefly wind
deposited. Unconformably overlying the whole series and in
sliarp contrast to the fine wind-blown stuff below it, is a third
series of coarse deposits about five hundred feet thick. The top-
most material, that forming the surface of llie desert upland, con-
sists of wind-blown sand now shifted by the wind and gathered
into sand dunes or irregular drifts, banks of white earth, **tierra
])lanf;a," and a pebble pavomoTit a few inches thick.

If the main facts of the above section are now summarized
they will facilitate an understanding of other sections about to be
described, inasmuch as the summary will in a measure anticipate

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 255

our conclusions concerning the origin of the deposits and their
subsequent history. The sediments in the Majes Valley between
Cantas and Jaguey consist of three series separated by two un-
conformities. The lowermost series is evenly bedded and rather
uniform in composition and topographic expression, standing
forth in huge cliffs several hundred feet high on the eastern side

ILO

COftST RANOe
LAS LOMHS

LA RINCONAOA

LAS PAMPAS

MOQUEGUA

SIERR.A

yrrt:

. -''

=c:i

■'-'^

!<2^

■^ STRUCTURE

UNKNOWN

Fig. 172 — Geologic relations of Coast Range, desert deposits, and Maritime
Cordillera at Moquegua, Peru. After G. I. Adams; Bol. de Minas del PerG, Vol. 2,
Ko. 4, 1906, p. 20.

of the valley. This lower series is overlain by a second series,
which consists of coarse conglomerate grading into sand and ulti-
mately into very fine fluffy wind-deposited sands and silts. The
lower series is much more deformed than the upper, showing that
the deforming movements of later geologic times have been much
less intense than the earlier, as if there had been a fading out or
weakening of the deforming agents. Finally there is a third
series several hundred feet thick which forms the top of the
section.

Three other sections may now be examined, one immediately
below Cantas, one just above, and one opposite Aplao. The sec-
tion below Cantas is sho\Mi
in Fig. 173, and indicates
a lower series of red sand-
stones crossed by vertical
faults and unconformably
overlain by nearly hori-
zontal conglomerates, sandstones, etc., and the whole faulted again
with an inclined fault having a throw of nearly 25°. A white to
gray sandstone unconformably overlying the red sandstone is
shoAvn interpolated between the lowermost and uppermost series,
the only example of its kind, however. No important differences

Fig. 173 — Sketch section to show structural
details on the walls of the Majes Valley near
Aplao, looking south.

256

THE ANDES OF SOUTHERN PERU

in lithograpliical character may be noted between these and the
beds of the preceding section.

Again just above Cantas on the east side of the valley is a
clean section exposing about two thousand feet of strata in a half
mile of distance. The foundation rocks are old quartzites and
shales in regularly alternating beds. Upon their uneven upper
surfaces are several thousand feet of red sandstones and conglom-
erates, which are both folded and faulted with the underlying
quartzites. Above the red sandstones is a thick series of gray
sandstones and silts w^hich makes the top of the section and uncon-
formably overlies the earlier series.

A similar succession of strata was observed at Aplao, still
farther up the Majes Valley, Fig. 174. A greatly deformed and
metamorphosed older series is unconformably overlaid by a great

Fig. 174 — The structural relations of the strata on the border of the Majes Valley
at Aplao, looking west. Field sketch from opposite side of valley. Height of section
about 3,000 feet; length about ten miles.

thickness of younger strata. The younger strata may be again
divided into two series, a lower series consisting chiefly of red
sandstones and an upper consisting of gray to yellow, and only
locally red sands of finer texture and more uniform composition.
The two are separated by an erosion surface and only the upper
series is tilted regionally seaward with faint local deformation;
the lower series is both folded and faulted with overthrusts ag-
gregating several thousand feet of vertical and a half mile of
horizontal displacement.

The above sections all lie on the eastern side of the Majes Val-
ley. From the upper edge of the valley extensive views were
gained of the strata on the opposite side, and two sections, though
they were not examined at close range, are at least worth com-
paring with those already given. From the narrows below Can-
tas the structure appears as in Figs. 175-17(1, and shows a deform-
ing movement succeeded by erosion in ;i lower series. The upper

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 257

series of sedimentary rock has suffered but slight deformation.
A still more highly deformed basal series occurs on the right of
the section, presumably the older quartzites. At Huancarqui, op-
posite Aplao, an extensive view was gained of the western side

Fig. 175 — Sketch section to show the structural details of the strata on the south
wall of the Majes Valley near Cantas. The section is two miles long.

of the valley, but the lower Tertiary seems not to be represented
here, as the upper undeformed series rests unconformably upon
a tilted series of quartzites and slates. Farther up the Cantas
valley (an hour's ride above Aplao) the Tertiary rests upon vol-
canic flows or older quartzites or the granite-gneiss exposed here
and there along the valley floor.

In no part of the sedimentaries in the Majes Valley were fos-
sils found, save in the now uplifted and dissected sands that over-
lie the upraised terraces along the coast immediately south of

Fig. 176 — Composite geologic section to show the structural relations of the
rocks on the western border of the Maritime Cordillera. The inclined strata at the
right bottom represent older rocks; in places igneous, in other places sedimentary.

Camana and also back of Mollendo. Like similar coastal deposits
elsewhere along the Peruvian littoral, the terrace sands are of
Pliocene or early Pleistocene age. The age of the deposits back
of the Coast Range is clearly greater than that of the coastal de-
posits, (1) since they involve two unconformities, a mile or more
of sediments, and now stand at least a thousand feet above the
highest Pliocene (or Pleistocene) in the Camana Valley, and (2)
because the erosion history of the interior sediments may be cor-
related with the physiographic history of the coastal terraces and
the correlation shows that uplift and dissection of the terraces
and of the interior deposits went hand in hand, and that the de-

258 THE ANDES OF SOUTHERN PERU

posits on the terraces may similarly be correlated with alluvial
deposits in the valley.

We shall now see what further ground there is for the de-
termination of the age of these sediments. Just below Chuqui-
bamba, where they first appear, the sediments rest upon a floor of
volcanic and older rock belonging to the great field now known
from e^ddence in many localities to have been formed in the early
Tertiary, and here known to be post-Cretaceous from the rela-
tions between Cretaceous limestones and volcanics in the Cota-
huasi Valley (see p. 247). Although volcanic flows were noted
interbedded with the desert deposits, these are few in number, in-
significant in volume, and belong to the top of the volcanic series.
The same may be said of the volcanic flows that locally overlie
the desert deposits. We have then definite proof that the sand-
stones, conglomerates, and related formations of the Majes Val-
ley and bordering uplands are older than the Pliocene or early
Pleistocene and younger than the Cretaceous and the older Ter-
tiary lavas. Hence it can scarcely be doubted that they represent
a considerable part of the Tertiary period, especially in view of
the long periods of accumulation which the thick sediments rep-
resent, and the additional long periods represented by the two
well-marked unconformities between the three principal groups of
strata.

If w^e now trace the physical history of the region we have
first of all a deep depression between the granite range along the
coast and the western flank of the Andes. Here and there, as in
the Vitor, the Majes, and other valleys, there were gaps through
the Coast Range. Nowhere did tlio relief of the coastal chain ex-
ceed 5,000 feet. The depression liad been partly filled in early
geologic (probably early Paleozoic) time by sediments later de-
formed and metamorplioscd so lluit tlicy are now quartzites and
shales. The greater resistance of the granite of the Coast Range
resulted in superior relief, while the older deformed sedimentaries
were deeply eroded, with the result that by the beginning of the
Tertiary the basin (luality of the depression was again empha-
sized. All these facts are expressed graphically in Fig. 171. On

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 259

the western flanks of the granite range no corresponding sedi-
mentary deposits are found in this latitude. The sea thus appears
to have stood farther west of the Coast Range in Paleozoic times
than at present.

For the later history it is necessary to assemble the various
Tertiary sections described on the preceding pages. First of all
we recognize three quite distinct types of accumulations, for which

Coarse alluvium alternating with fine wind-
blown desert deposits.
Upper sandstone series.

Lower sandstone series.
Quartzites.

Volcanic flows.

Granite-gneiss.

Fig. 177 — Composite structure section at Aplao.

we shall have to postulate three sets of conditions and possibly
three separate agents. The first or lowermost consists of even-
bedded deposits of red and gray sandstones, the former color pre-
dominating. The material is in general well-sorted save locally,
where lenses and even thin beds of conglomerate have been devel-
oped. There is, however, about the whole series a uniformity and
an orderliness in striking contrast to the coarse, cross-bedded, and
irregular material above the unconformity. On their northeast-
ern or inner margin the sandstones are notably coarser and
thicker, a natural result of proximity to the mountains, the source
of the material. The general absence of wind-blown deposits is
marked; these occur entirely along the eastern and northern por-
tions of the deposits and are recognized (1) by their peculiar
cross-bedding, and (2) by the fact that the cross-bedding is di-
rected northeastward in a direction contrary to the regional dip
of the series, a condition attributable to the strong sea breezes
that prevail every afternoon in this latitude.

The main body of the material is such as might be deposited
on the wide flood plains of piedmont streams during a period of

260 THE ANDES OF SOUTHERN PERU

prolonged erosion on surrounding highlands that served as the
feeding grounds of the streams. The alternations in the charac-
ter of the deposits, alternations which, in a general view, give a
banded appearance to the rock, are produced by successions of
beds of fine and coarse material, though all of it is sandstone.
Such successions are probably to be correlated with seasonal
changes in the volume and load of the depositing streams.

To gain an idea of the conditions of deposition we may take
the character of the sediments as described above, and from them
draw deductions as to the agents concerned and the manner of
their action.

We may also apply to the area the conclusions drawn from
the study of similar deposits now in process of formation. We
have between the coast ranges of northern Chile and the western
flanks of the Cordillera Sillilica, probably the best example of
piedmont accumulation in a dry climate that the west coast of
South America affords.

Along the inner edge of the Desert of Tarapaca, roughly be-
tween the towns of Tarapaca and Quillagua, Chile, the piedmont
gravels, sands, silts, and muds extend for over a hundred miles,
flanking the western Andes and forming a transition belt between
these mountains and the interior basins of the coast desert. The
silts and muds constitute the outer fringe of the piedmont and
are interrupted here and there where sands are blown upon them
from the higher portions of the piedmont, or from the desert
mountains and plains on the seaward side. Practically no rain
falls upon the greater part of the desert and the only water it re-
ceives is that borne to it by the piedmont streams in the early
summer, from the rains and melted snows of the high plateau and
mountains to tlic eastward. These temporary streams spread
iif)on the outer edge of tlie piedmont a wide sheet of mud and silt
which then dries and becomes cracked, the curled and warped
plates retaining their cliaracter until th(? next wet season or until
covered witli wind-blown sand. The wind-driven sand fills the
cracks in the muds and is even drifted under the edges of the up-
curled plates, filling the spaces completely. Over this combined

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 261

fluvial and seolian deposit is spread the next layer of mud, which
frequently is less extensive than the earlier deposits, thus giving
abundant opportunity for the observation of the exact manner of
burial of the older sand-covered stratum.

Now while the alternations are as marked in Peru as in Chile,
it is noteworthy that the Tertiary material in Peru is not only
coarse throughout, even to the farthest limits of the piedmont,
but also that the alternating beds are thick. Moreover, there are
only the most feeble evidences of wind action in the lowermost.
Tertiary series. I was prepared to find curled plates, wind-blown,
sands, and muds and silts, but they are almost wholly absent. It
is, therefore, concluded that the dryness was far less extreme thai^
it is today and that full streams of great competency flowed vigor-
ously down from the mountains and carried their loads to the in-
ner border of the Coast Range and in places to the sea. ^

The fact that the finer material is sandy, not clayey or silty,
that it almost equals in thickness the coarser layers, and that its
distribution appears to be co-extensive with the coarser, warrants
the conclusion that it too was deposited by competent streams of
a type far different from the withering streams associated mth
piedmont deposits in a thoroughly arid climate like that of today.
Both in the second Tertiary series and on the present surface are
such clear examples of deposits made in a drier climate as to leave
little doubt that the earliest of the Tertiary strata of the Majes
Valley were deposited in a time of far greater rainfall than the
present. It is further concluded that there was increasing dry-
ness, as shown by hundreds of feet of wind-blown sand near the
top of the section. But the growing dryness was interrupted by
at least one period of greater precipitation. Since that time there
has been a return to the dry climate of a former epoch.

Uplift and erosion of the earliest of the Tertiary deposits of
the Majes Valley is indicated in two w^ays: (1) by the deformed
character of the beds, and (2) by the ensuing coarse deposits
which were derived from the invigorated streams. Without
strong deformations it would not be possible to assign the in-
creased erosion so confidently to uplift; with the coarse deposits

262 THE ANDES OF SOUTHERN PERU

that succeed the unconformity we have evidence of accumulation
under conditions of renewed uplift in the mountains and of full
streams competent to remove the increasing load.

It is in the character of the sediments toward the top of the
Tertiary that we have the clearest evidence of progressive desic-
cation of the climate of the region. The amount of wind-blown
material steadily increases and the uppermost five hundred feet is
composed predominantly, and in places exclusively, of this ma-
terial. The evidences of wind action lie chiefly in the fine (in
places fluffy) nature of the deposits, their uniform character, and
in the tangency of the layers with respect to the surface on which
they w^ere deposited. There are three diagnostic structural fea-
tures of great importance : the very steep dip of the fine laminae ;
the peculiar and harmonious blending of their contacts; the man-
ner in which the highly inclined laminae cut off and succeed each
other, whereby quite bewildering changes in the direction of dip
of the inclined beds are brought about on any exposed plane.
Some of these features require further discussion.

It is well known that the front of a sand dune generally con-
sists of sand deposited on a slope inclined at the angle of repose,
say between 30° and 35°, and rolled into place up the long back
slope of the dune by the wind. It has not, however, been gener-
ally recognized that the angle of repose may be exceeded (a) when
there exists a strong back eddy or (b) when the wind blows vio-
lently and for a short time in the opposite direction. In either case
sand is carried up the short steep slope of the dune front and
accumulated at an angle not infrequently running up to 43° and
48°- and locally, and under the most favorable circumstances, in
excess of 50°. The conditions under which tlioso steep angles are
attained are undoubtedly not universal, but Ihey can be found in
some parts of almost any desert in the world. They appear not
to bo present whore the sand grains are of uniform size tlirough-
out, since that loads to rolling. They are found rather where there
is a certain limited variation in size that promotes packing.
Packing and tlif (IfNcldiiiiicnf of sloo]) slopes are also facilitated
ill parts of the coastal desert of Peru by a cloud canopy that hangs

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 263

over the desert in the early morning, that in the most favorable
places moistens even the dune surfaces and that has least penetra-
tion on the steep semi-protected dune fronts. Sand later blown
up the dune front or rolled down from the dune crest is en-
couraged to remain near the cornice on an abnormally steep slope
by the attraction which the slightly moister sand has for the dry
grains blown against it. Since dunes travel and since their front
layers, formed on steep slopes, are cut off to the level of the sur-
face in the rear of the dune, it follows that the steepest dips in
exposed sections are almost always less than those in existing
dunes. Exceptions to the rule will be noted in filled hollows not
re-excavated until deeply covered by wind-blown material. These,
re-exposed at the end of a long period of wind accumulation, may
exhibit even the maximum dips of the dune cornices. Such will
be conspicuously the case in sections in aggraded desert deposits.
On the border of the Majes Valley, from 400 to 500 feet of wind-
accumulated deposits may be observed, representing a long period
of successive dune burials.

The peculiar blending of the contact lines of dune laminae, re-
lated to the tangency commonly noted in dune accumulations, is
apparently due to the fact that the wind does not require a graded
surface to work on, but blows uphill as well as down. It is pres-
ent on both the back-slope and the front-slope deposits. Its finest
expression appears to be in districts where the dune material was
accumulated by a violent wind whose effects the less powerful
winds could not destroy.

It is to the ability of the wind to transport material against,
as well as with, gravity, that we owe the third distinct quality of
dune material, the succession of flowing lines, in contrast to the
succession of now flat-lying now steeply inclined beds character-
istic of cross-bedded material deposited by water. One dune trav-
els across the face of the country only to be succeeded by another. '^
Even if wind aggradation is in progress, the plain-like surface in
the rear of a dune may be excavated to the level of steeply inclined

° The best photograph of this condition which I have yet seen is in W. Sievers, Siid-
und Mittelamerika, second ed., 1914, Plate 15, p. 358.

264i THE ANDES OF SOUTHERN PERU

beds upon whose truncated outcrop other inclined beds are laid,
Fig. 178. The contrast to these conditions in the case of aggrada-
tion by water is so clearly and easily inferred that space vdW not
be taken to point them out. It is also true as a corollary to the
above that the greater part of a body of wind-drifted material
will consist of cross-bedded layers, and not a series of evenly
divided and alternating flat-lying and cross-bedded layers which
result from deposition in active and variable currents of water.

The caution must of course be observed that wind action and
water action may alternate it^ a desert region, as already de-
scribed in Tarapaca in north^ri Chile, so that the whole of a de-
posit may exhibit an alternate, > of cross-bedded and flat-lying lay-
ers ; but the former only are drie to wind action, the latter to water
action. >k

Finally it may be noted T at the sudden, frequent, and diversi-
fied dips in the cross-beddin- are peculiarly characteristic of wind
action. Although one sees ii/ a given cross-section dips apparently
directed only toward the lerL or the right, excavation will supply
a third dimension from which the true dips may be either ob-
served or calculated. These show an almost infinite variety of
directions of dip, even in f stricted areas, a condition due to the
following causes :

(1) the curved fronts of sand dunes, which produce dips con-
centric with respect to a point and ranging through 180° of arc;
(2) the irregular character of sand dunes in many places, a con-
dition due in turn to (a) tlie changeful character of the strong
wind (often not the prevailing wind) to wliicli the formation of
the dunes is due, and (b) the influence of the local topography
upon wind directions within short distances or upon winds of
different directions in which a slight change in wind direction
is followed by a large cliange in the local currents; (3) the fact
tliat all combinations ;iro possible between the erosion levels of
the wind in successive generations of dunes blown across a given
area, hence any condition at a given level in a dune may be com-
bined with amj other condition of a succeeding dune; (4) varia-
tions in the sizes of successive dunes will lead to further contrasts

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 2G5

Fig. 178 — Plan and cross-sections of superimposed sand dunes of conventional
outline. In the sections, dune A is supposed to have left only a small
basal portion to be covered by dune B. In the same way dune C has advanced to cover
both A and B. The basal portions that have remained are exaggerated vertically in
order to display the stratification. It is obviously not necessary that the dunes should
all be of the same size and shape and advancing in the same direction in order to
have the tangential relations here displaj'ed. Nor need the aggrading material be
derived from true dunes. The results would be the same in the case of sand drifts with
their associated wind eddies. All bedded wind-blown deposits would have the same
general relations. No two successive deposits, no matter from what direction the
successive drifts or dunes travel, would exactly correspond in direction and amount
of dip.

266 THE ANDES OF SOUTHERN PERU

not only in the scale of the features but also in the direction and
amount of the dips.

Finally, we may note that a section of dune deposits has a dis-
tinctive feature not exhibited by water deposits. If the foreset
beds of a cross-bedded water deposit be exjDosed in a plane
parallel to the strike of the beds, the beds will appear to be hori-
zontal. They could not then be distinguished from the truly
horizontal beds above and below them. But the conditions of mnd
deposition we have just noted, and chiefly the facts expressed by
Fig. 178, make it impossible to select a position in which both
tangency and irregular dips are not well developed in a wind de-
posit. I believe that wo have in the foregoing facts and inferences
a means for the definite separation of these two classes of de-
posits. Difficulties will arise only when there is a quick succession
of wind and water action in time, or where the wind produces
powerful and persistent effects without the actual formation of
dunes.

The latest known deposits in the coastal region are found sur-
mounting the terrace tops along the coast between Camana and
Quilca, where they form deposits several hundred feet thick in
places. The age of these deposits is determined by fossil evidence,
and is of extraordinary interest in the determination of the age of
the great terraces upon which they lie. They consist of alternating
beds of coarse and fine material, the coarser increasing in thick-
ness and frequency toward the bottom of the section. It is also
near the bottom of the section that fossils are now found; the
higher members are locally saline and throughout there is a
marked inclination of the beds toward the present shore. The de-
posits appear not to have been deriv<Ml from the underlying gran-
ite-gneiss. They arc distributed most abundantly near the mouths
of llic larger streams, as near llic \'i<or at (j)iiilca, and <lie Majes
at (aiiiaiia. Flscwlici-c llic Icnace summit is swept clean of
waste, except where local clay de])osits lie in the ravines, as back
of ^follendo and wlior(> 'Micrras blancas" lia\'o been accumulated
by the wind.

These coastal deposits were laid down upon a dissected ter-

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 267

race up to five miles in width. The degree of dissection is varia-
ble, and depends upon the relation of the through-flowing streams
to the Coast Range. The Vitor and the Majes have cut down
through the Coast Range, and locally removed the terrace ; smaller
streams rising on the flanks of the Coast Range either die out
near the foot of the range or cross it in deep and narrow valleys.
The present drainage on the seaward slopes of the Coast Range
is entirely ineffective in reaching the sea, as was seen in 1911, the
wettest season known on the coast in years and one of the wettest
probably ever observed on this coast by man.

In consequence of their deposition on a terrace that ranges in
elevation from zero to 1,500 feet above sea level, the deposits of
the coast are very irregularly disposed. But in consequence of
their great bulk they have a rather smooth upper surface, grada-
tion having been carried to the point where the irregularities of
the dissected terrace were smoothed out. Their general uniform-
ity is broken where streams cross them, or where streams crossed
them during the wetter Pleistocene. Their elevation, several hun-
dred feet above sea level, is responsible for the deep dissection
of their coastal margin, where great cliffs have been cut.

PLEISTOCENE

The broad regional uplift of the Permdan Andes in late Ter-
tiary and in Pleistocene times carried their summits above the
level of perpetual snow. It is still an open question whether or not
uplift was sufficiently great in the early Pleistocene to be in-j
fluenced by the first glaciations of that period. As yet, there arel
evidences of only two glacial invasions, and both are considered
late events on account of the freshness of their deposits and th^
related topographic forms. The coarse deposits — nearly 500 feet
thick — that form the top of the desert section described above
clearly indicate a wetter climate than prevailed during the)
deposition of the several hundred feet of wdnd-blown deposits be-
neath them. But if our interpretation be correct these deposits
are of late Tertiary age, and their character and position arey
taken to indicate climatic changes in the Tertiary, They may

268 THE ANDES OF SOUTHERN PERU

have been the mild precursors of the greater climatic changes of
glacial times. Certain it is that they are quite unlike the mass
of the Tertiary deposits. On the other hand they are separated
from the deposits of known glacial age by a time interval of great
length — an epoch in which was cut a benched canyon nearly a mile
deep and three miles wide. They must, therefore, have been
formed when the Andes were thousands of feet lower and unable
to nourish glaciers. It was only after the succeeding uplifts had
raised the mountain crests well above the frost line that the rec-
ords of oscillating climates were left in erratic deposits, troughed
valleys, cliffed cirques and pinnacled divides.

The glacial forms are chiefly at the top of the country; the
glacial deposits are chiefly in the deep valleys that were carved
before the colder climate set in. The rock waste ground up by
the ice was only a small part of that delivered to the streams in
glacial times. EveryAvhere the wetter climate resulted in the
partial stripping of the residual soil gathered upon the smooth
mature slopes formed during the long Tertiary cycle of erosion.
This moving sheet of waste as well as the rock fragments carried
away from the glacier ends were strewn along the valley floors,
forming a deep alluvial fill. Thereby the canyon floors were ren-
dered habitable.

In the chapters on human geography we have already called
attention to the importance of the U-shaped valleys carved by the
glaciers. Their floors are broad and relatively smooth. Their
walls restrain the live stock. They are sheltered though lofty.
But all the human benefits conferred by ice action are insig-
nificant beside those due to the general shedding of waste from
the cold upper surfaces to the warm levels of the valley floors.
The alluvium-filled valleys are the seats of dense populations. In
the lowest of them tropical and sub-tropical products are raised,
like sugar-cane and cotton, in a soil lliat once lay on the smooth
upper slopes of mountain Sfjurs or \h:\\ was ground fine on the bed
of an Alpine glacier.

The Pleistocene deposits fall into three well-defined groups:
(1) glacial accumulations at the valley heads, (2) alluvial deposits

•"ji:i.-u,V^ji;j!l«i.~,ur>X< >>.

Fig. 179 — Snow fields on the summit of the Cordillera Vilcapanipa near OUantay-
tambo. A huge glacier once lay in the steep canyon in the background and descended
to the notched terminal moraine at the canyon mouth. In places the glacier was
over a thousand feet thick. From the terminal moraine an enormous alluvial fan extends
forward to the camera and to the opposite wall of the Urubamba Valley. It is'
confluent with other fans of the same origin. See Fig. 180. In the foreground are
flowers, shrubs, and cacti. A few miles below Urubamba at 11,500 feet.

Fig. 180.

Fi<; isl.

Fro ISO — rriil);iiiilj;i N'allcy licLwciii Olliiiitiiytaiiiljo ;iiiil 'l'i)iiiii((iy, sliowiiij; (1)
more inodcrato upper hlopoH and Htccpor lower HlopCH of tin- Iwn cvdc inouiitain spurw;
(2) the exteiiHivc alluvial dcpoHits of tluj valley, conHistiiij^ diiilly nf <()nllmiif .illuvial
fanH heading in the glaeiated mounlaiiiH on the left. >Seo Fig. \1'.K

Flo IHl — (;i(Kiii! features of the Centnil KangeH (see Fig. '204). iiiigc Inieral
mor.'iines Iniilt liy ier streams trilmtary to the main valley nortli of ('h\i(|uil)aml)illa.
Ihat thf tributaries persisted long afU-r the main valley heeame free of ice is Hhown
by the descent of tlie lateral moraines over the steep border of the main valley and
down to the Moor of it.

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 269

in the valleys, and (3) lacustrine deposits formed on the floors of
temporary lakes in inclosed basins. Among these the most varia-
ble in form and composition are the true glacier-laid deposits at
the valley heads. The most extensive are the fluvial deposits ac-
cumulated as valley fill throughout the entire Andean realm.
Though important enough in some respects the lacustrine deposits
are of small extent and of rather local significance. Practically
none of them fall within the field of the present expedition ; hence
we shall describe only the first two classes.

The most important glacial deposits were accumulated in the
eastern part of the Andes as a result of greater precipitation, a
lower snowline, and catchment basins of larger area. In the
Cordillera Vilcapampa glaciers once existed up to twelve and fif-
teen miles in length, and those several miles long were numerous
both here and throughout the higher portions of the entire Cordil-
lera, save in the belt of most intense volcanic action, which coin-
cides with the driest part of the Andes, where the glaciers were
either very short or wanting altogether.

Since vigorous glacial action results in general in the cleaning
out of the valley heads, no deposits of consequence occur in these
locations. Down valley, however, glacial deposits occur in the
form of terminal moraines of recession and ground moraines.
The general nature of these deposits is now so well known that
detailed description seems quite unnecessary except in the case
of unusual features.

It is noteworthy that the moraines decrease in size up valley
since each valley had been largely cleaned out by ice action before
the retreat of the glacier began. Each lowermost terminal
moraine is fronted by a great mass of unsorted coarse bowldery
material forming a fill in places several hundred feet thick, as be-
low Choquetira and in the Vilcapampa Valley between Vilca-
bamba and Puquiura. This bowldery fill is quite distinct from the
long, gently inclined, and stratified valley train below it, or the
marked ridge-like moraine above it. It is in places a good half
mile in length. Its origin is believed to be due to an overriding
action beyond the last terminal moraine at a time when the ice

270 THE ANDES OF SOUTHERN PERU

was well charged with debris, an overriding not marked by
morainal accumulations, chiefly because the ice did not maintain
an extreme position for a long period.

In the vicinity of the terminal moraines the alluvial valley fill
is often so coarse and so unorganized as to look like till in the cut
banks along the streams, though its alluvial origin is always
shown by the topographic form. This characteristic is of special
geologic interest since the form may be concealed through deposi-
tion or destroyed by erosion, and no condition but the structure
remain to indicate the manner of origin of the deposit. In such
an event it would not be possible to distinguish between alluvium
and till. The gravity of the distinction appears when it is kno^m
that such apparently unsorted alluvium may extend for several
miles forward of a terminal moraine, in the shape of a wide-
spreading alluvial fan apparently formed under conditions of ex-
tremely rapid aggradation. I suppose it would not be doubted in
general that a section of such stony, bowldery, unsorted material
two miles long would have other than a glacial origin, yet such
may be the case. Indeed, if, as in the Urubamba Valley, a future
section should run parallel to the valley across the heads of a
great series of fans of similar composition, topographic form, and
origin, it would be possible to see many miles of such material.

The depth of the alluvial valley fill due to tributary fan ac-
cumulation depends upon both the amount of the material and the
form of the valley. Below Urubamba in the Urubamba Valley a
fine series is displayed, as shown in Fig. 180. The fans head in
valleys extending up to snow-covered summits upon whose flanks
living glaciers are at work today. Their heads are now crowned
by terminal moraines and both moraines and alluvial fans are in
process of dissection. The height and extent of the moraines and
the alluvial fans are in rough proportion and in turn reflect the
lieight, elevation, and extent of the valley heads which served as
fields of nourishment for the Pleistocene glaciers. Whore the fans
were deposited in narrow valleys the effect was to increase the
thickness of the deposits at the expense of their area, to dam the
drainage lines or displace them, and to so load the streams that

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 271

they have not yet cleared their beds after thousands of years of
work under torrential conditions.

Below Urubamba the alluvial fans entering the main valley
from the east have pushed the river against its western valley
wall, so that the river flows on one side against rock and on the
other against a hundred feet of stratified material. In places, as
at the head of the narrows on the valley trail to Ollantaytambo,
a flood plain has been formed in front of the scarp cut into the
alluvium, while the edge of the dissected alluvial fans has been
sculptured into erosion forms resembling bad-lands topography.
On the western side of the valley the alluvial fans are very small,
since they are due to purely local accumulations of waste from
the edge of the plateau. Glaciation has here displaced the river.
Its effects will long be felt in the disproportionate erosion of the
western wall of the valley.

By far the most interesting of the deposits of glacial time are \
those laid down on the valley floors in the form of an alluvial fill.
Though such deposits have
greater thickness as a rule
near the nourishing mo-
raines or bordering allu-
vial fans at the lower ends
of the valleys, they are
everywhere important in
amount, distinctive in topo-
graphic form, and of amaz-
ingly wide extent. They
reach far into and possibly
across the Amazon basin,
they form a distinct though
small piedmont fringe along the eastern base of the Andes, and
they are universal throughout the Andean valleys. That a deposit
of such volume — many times greater than all the material accumu-
lated in the form of high-level alluvial fans or terminal moraines
— should originate in a tropical land in a region that suffered but
limited Alpine glaciation vastly increases its importance.

Fig. 182 — Dissected alluvial fans on the
border of the Urubamba Valley near Hacienda
Chinche. A characteristic feature of the
valleys of the Peruvian Andes below the zone
of glaciation but within the limits of its ag-
graditional effects. Through alluviation the
valleys and basins of the Andean Cordillera,
and vast areas of the great Amazon plains east
of it, felt the effects of the glacial conditions
of a past age.

272

THE ANDES OF SOUTHERN PERU

The fill is composed of both fine aud coarse material laid dovni
by water in steep valley floors to a depth of many feet. It breaks
the steep slope of each valley, forming terraces with pronounced
frontal scarps facing the river. On the raw bluffs at the scarps
made by the encroaching stream good exposures are afforded.
At Chinche in the Urubamba Valley above Santa Ana, the material
is both sand and clay with an important amount of gravel laid
down with steep valleyward inclination and under torrential con-
ditions; so that within a
given bed there may be an
apparent absence of lamina-
tion. Almost identical con-
ditions are exhibited fre-
, quently along the railway to
Cuzco in the Vilcanota Val-
ley. The material is mixed
sand and gravel, here and
there running to a bowldery
or stony mass where acces-
sions have been received

4J72J1L

4,l45nL
33S2K

•■"-"--";;■ VALUEV nil

Fig. 183 — Two-cycle slopes and alluvial fill
between Huicliihua and Cliuquibambiila. The
steep slopes on the inner valley border are in
many places vertical and rock cliffs are every-
where abundant. Mature slopes have their
greatest development here between 13,500 and
15,000 feet (4,110 to 4,570 m.). Steepest ma-
ture slopes run from 15° to 21°. Least steep
are the almost level spur summits. The depths
of the valley fill must be at least 300, and may fi'om SOmC SOUrCC nearby
possibly be 500 feet. The break between valley
fill and steep slopes is most pronounced where
the river runs along the valley wall or under-
cuts it; least pronounced where alluvial fans
spread out from the head of some ravine. It
is a bowldery, stony fill almost everywhere
terraced and cultivated.

It is modified along its mar-
gin not only in topographic
form but also in composition
by small tributary alluvial
fans, though these in general
constitute but a small part of the total mass. At Cotahuasi, Fig.
29, there is a remarkable fill at least four hundred feet deep in
many places where the river has exposed fine sections. The
(Icjdli of the (ill is, Ik.wcnci-, not determined by the height of the
erosion bluffs cut into it, since the bed of the river is made of the
same material. The rock floor of the valley is probably at least
an additional Imndred feet below the present level of tlio river.

Similar conditions are well displayed at TTuadquina, where a
fine series of terraces at llie lower ond of llic I'orontoy Canyon
break the descent of tlio environing slopes; also in the Urubamba

PHYSIOGRAPHIC AND GEOLOGIC DEVELOPMENT 273

Valley below Rosalina, and again at the edge of the mountains at
the Pongo de Mainique. It is exhibited most impressively in the
Majes Valley, where the bordering slopes appear to be buried
knee-deep in waste, and where from any reasonable downward ex-
tension of rock walls of the valley there would appear to be at;
least a half mile of it. It is doubtful and indeed improbable that/
the entire fill of the Majes Valley is glacial, for during the Pliocent
or early Pleistocene there was a submergence which gave op-
portunity for the partial filling of the valley with non-glacial al-
luvium, upon which the glacial deposits were laid as upon a flat
and extensive floor that gives an exaggerated impression of their
depth. However, the head of the Majes Valley contains at least
six hundred feet and probably as much as eight hundred feet of
alluvium now in process of dissection, whose coarse texture
and position indicates an origin under glacial conditions. The
fact argues for the great thickness of the alluvial material of the
lower valley, even granting a floor of Pliocene or early Pleistocene
sediments. The best sections are to be found just below Chu-
quibamba and again about halfway between that city and Aplao,
whereas the best display of the still even-floored parts of the
valley are between Aplao and Cantas, where the braided river
still deposits coarse gravels upon its wade flood plain.

CHAPTEE XVI
GLACIAL FEATURES

THE SNOWLINE

South America is classical ground in the study of tropical
snowlines. The African mountains that reach above the snowline
in the equatorial belt — Euwenzori, Kibo, and Kenia — have only-
been studied recently because they are remote from the sea and
surrounded by bamboo jungle and heavy tropical forest. On the
other hand, many of the tropical mountains of South America lie
so near the west coast as to be visible from it and have been
studied for over a hundred years. From the days of Humboldt
(1800) and Boussingault (1825) down to the present, observations
in the Andes have been made by an increasing number of scientific
travelers. The result is a large body of data upon which compara-
tive studies may now be profitably undertaken.

Like scattered geographic observations of many other kinds,
the earlier studies on the snowline have increased in value with
time, because the snowline is a function of climatic elements that
are subject to periodic changes in intensity and cannot be under-
stood by reference to a single observation. Sitice the discovery
of physical proofs of climatic changes in short cycles, studies
have been made to determine the direction and rate of change of
the snowline the world over, with some very striking results.

It has been found ^ that the changes run in cycles of from
thirty to thirty- five years in length and that the northern and
southern hemispheres appear to bo in opposite phase. For ex-
ample, since 1885 the snowline in the southern hemisphere has
been decreasing in elevation in nine out of twelve cases by the
average amount of nine hundred feet. With but a single excep-

• Pnschin^frr, Die Rolinorprrnzf in vcrschicdonon Klimaten. Pctor. Mitt.
Erganz'licft, Nr. 173. 1912, pp. 92-0.1.

274

GLACIAL FEATURES 275

tion, the snowline in the northern hemisphere has been rising
since 1890 with an average increase of five hundred feet in sixteen
cases. To be sure, we must recognize that the observations upon
which these conclusions rest have unequal value, due both to per-
sonal factors and to differences in instrumental methods, but that
in spite of these tendencies toward inequality they should agree
in establishing a general rise of the snowline in the northern
hemisphere and an opposite effect in the southern is of the high-
est significance.

It must also be realized that snowline observations are alto-
gether too meager and scattered in view of the abundant op-
portunities for making them, that they should be standardized,
and that they must extend over a much longer period before they
attain their full value in problems in climatic variations. Once
the possible significance of snowline changes is appreciated the
number and accuracy of observations on the elevation and local
climatic relations of the snowline should rapidly increase.

In 1907 I made a number of observations on the height of the
snow^line in the Bolivian and Chilean Andes betw^een latitudes 17°
and 20° south, and in 1911 extended the w^ork northward into the
Peruvian Andes along the seventy-third meridian. It is proposed
here to assemble these observations and, upon comparison with
published data, to make a few interpretations.

From Central Lagunas, Chile, I went northeastward via Pica
and the Huasco Basin to Llica, Bolivia, crossing the Sillilica Pass
in May, 1907, at 15,750 feet (4,800 m.). Perpetual snow lay at an
estimated height of 2,000-2,500 feet above the pass or 18,000 feet
(5,490 m.) above the sea. Two weeks later the Huasco Basin,
14,050 feet (4,280 m.), was covered a half -foot deep with snow and
a continuous snow^ mantle extended dovna. to 13,000 feet. Light
snows are reported from 12,000 feet, but they remain a few hours
only and are restricted to the height of exceptionally severe w^in-
ter seasons (June and early July). Three or four distant snow-
capped peaks were observed and estimates made of the elevation
of the snowline between the Cordillera Sillilica and Llica on the
eastern border of the Maritime Cordillera. All observations

276 THE ANDES OF SOUTHERN PERU

agreed in gning an elevation mucli in excess of 17,000 feet. In
general the values run from 18,000 to 19,000 feet (5,490 to 5,790
m.). Though the bases of these figures are estimates, it should
be noted that a large part of the trail lies between 14,000 and
16,000 feet, passing mountains snow-free at least 2,000 to 3,000
feet higher, and that for general comparisons they have a distinct
value.

In the Eastern Cordillera of Boli^da, snow was observed on
the summit of the Tunari group of peaks northwest of Cocha-
bamba. Steinmann, who visited the region in 1904, but did not
reach the summit of the Tunari group of peaks, concludes that
the limit of perpetual snow should be placed above the highest
point, 17,300 (5,270 m.) ; but in July and August, 1907, I saw a
rather extensive snow cover over at least the upper 1,000 feet, and
what appeared to be a very small glacier. Certain it is that the
Cochabamba Indians bring clear blue ice from the Tunari to the
principal hotels, just as ice is brought to Cliza from the peaks
above Arani. On these grounds I am inclined to place the snow-
line at 17,000 feet (5,180 m.) near the eastern border of the
Eastern Cordillera, latitude 17° S. At 13,000 feet, in July, 1907,
snow occurred in patches only on the pass called Abre de Malaga,
northeast of Colomi, 13,000 feet, and fell thickly while we were
descending the northern slopes toward Corral, so that in the early
morning it extended to the cold timber line at 10,000 feet. In a
few hours, however, it had vanished from all but the higher and
the shadier situations.

In the Vilcanota knot above the divide between the Titicaca
and Vilcanota hydrographic systems, the elevation of the snow-
lino was 16,300+ feet (4,970 m.) in September, 1907. On the
Cordillera Real of Bolivia it is 17,000 to 17,500 feet on the north-
east, but falls to 16,000 feet on the southwest above La Paz. In
the first week of July, ]911, snow fell on the streets of Cuzco
(11,000 feet) and remained for over an liour. The heights north
of San Geronimo (16,000 feet) miss the limit of perpetual snow
and arc snow-covered only a f(!W months each year.

In taking observations on the snowline along the seventy-third

GLACIAL FEATURES 277

meridian I was fortunate enough to have a topographer the
heights of whose stations enabled me to correct the readings of
my aneroid barometer whenever these were taken off the line of
traverse. Furthermore, the greater height of the passes — 15,000
to 17,600 feet — brought me more frequently above the snowline
than had been the case in Bolivia and Chile. More detailed ob-
servations were made, therefore, not only upon the elevation of
the snowline from range to range, but also upon the degree of
canting of the snowline on a given range. Studies were also made
on the effect of the outline of the valleys upon the extent of the
glaciers, the influence on the position of the snowline of mass ele-
vation, precipitation, and cloudiness.

Snow first appears at 14,500 feet (4,320 m.) on the eastern
flanlvs of the Cordillera Vilcapampa, in 13° south latitude. East
of this group of ridges and peaks as far as the extreme eastern
border of the mountain belt, fifty miles distant, the elevations
decrease rapidly to 10,000 feet and lower, with snow remaining
on exceptionally high peaks from a few hours to a few months.
In the winter season snow falls now and then as low as 11,500 feet,
as in the valley below Vilcabamba pueblo in early September,
1911, though it vanishes like mist with the appearance of the sun
or the warm up-valley winds from the forest. Storms gather
daily about the mountain summits and replenish the perpetual
snow above 15,000 feet. In the first pass above Puquiura we en-
countered heavy snow banks on the northeastern side a hundred
feet below the pass (14,500 feet), but on the southwestern or lee-
ward side it is five hundred feet lower. This distribution is ex
plained by the lesser insolation on the southwestern side, the im
mediate drifting of the clouds from the windward to the leeward
slopes, and to the mutual intensification of cause and effect bjr
topographic changes such as the extension of collecting basins and]
the steeping of the slopes overlooking them vdth. a correspond-
ing increase in the duration of shade.

It is well known that with increase of elevation and there-
fore of the rarity of the air there is less absorption of the sun's
radiant energy, and a corresponding increase in the degree of in-

278 THE ANDES OF SOUTHERN PERU

solation. It follows, therefore, that at high altitudes the contrasts
between sun and shade temperatures will increase. Frankland -
has sho^\Ti that the increase may run as high as 500 per cent be-
tween 100 to 10,000 feet above the sea. I have noted a fall of tem-
perature of 15° F. in six minutes, due to the obscuring of the sun
by cloud at an elevation of 10,000 feet above Huichihua in the
Central Ranges of Peru. Since the sun shines approximately
half the time in the snow-covered portions of the mountains and
since the tropical Andes are of necessity snow^-covered only at
lofty elevations, this contrast between shade and sun tempera-
tures is by far the most powerful factor influencing differences in
elevation of the snowline in Peru.

To the drifting of the fallen snow is commonly ascribed a
large portion of this contrast. I have yet to see any evidence of
its action near the snowline, though I have often observed it,
especially under a high wind in the early morning hours at con-
siderable elevations above the snowline, as at the summits of lofty
peaks. It appears that the lower ranges bearing but a limited
amount of snow are not subject to drifting because of the wetness
of the snow, and the fact that it is compacted by occasional rains
and hail storms. Only the drier snow at higher elevations and
under stronger winds can be effectively dislodged.

The effect of unequal distribution of precipitation on the Avind-
ward and leeward slopes of a mountain range is in general to de-
press the snowline on the windward slopes where the greater
amount falls, but this may be offset in high altitudes by tempera-
ture contrasts as in the westward trending Cordillera Vilcapampa,
where north and south slopes are in opposition. If the Cordillera
Vilcapampa ran north and south we should have the windward
and leeward slopes equally exposed to the sun and the snowline
would lie at a lower elevation on the eastern side. Among all the
Iranges the slopes have decreasing precipitation to the leeward,
that is, westerly. The second and third passes, between Arma and
Choquetira, are snow-free (though their elevations equal those of

' Ilann, IFandl.ook of Climatology, Tart 1, traim. by Ward, 190:5, p. 232.

GLACIAL FEATURES 279

the first pass) because they are to leeward of the border range,
hence receive less precipitation. The depressive effect of increased
precipitation on the snowline is represented by A-B, Fig. 184; in
an individual range the effect of heavier precipitation may be off-
set by temperature contrasts between shady and sunny slopes, as
shown by the line a-b in the same figure.

The degree of canting of the snowline on opposite slopes of
the Cordillera Vilcapampa varies between 5° and 12°, the higher
value being represented four hours southwest of Arma on the
Choquetira trail, looking
northeast. A general view
of the Cordillera looking
east at this point (Fig. 186),

, ,, „ ,, Fig. 184 — To illustrate the canting of the

shows the appearance of the g^^wline. a-b is the snowline depressed

snowline as one looks along toward the north (right) in response to heavier

l^r^■,r>,^, -r precipitation. The line a-h represents a de-

the flanks of the range. In ^^^^^.^^ -^ ^^^ ^pp^^.^ ^.^^^^.^^ ^^^ ^^ ^^^

detail the snowline is fur- different degree of insolation on the northern
■ 1 T J T 1 J (sunny) and southern (shady) slopes.

ther complicated by topog-
raphy and varying insolation, each spur having a snow- clad and
snow-free aspect as sho^\^l in the last figure. The degree of dif-
ference on these minor slopes may even exceed the difference
between opposite aspects of the range in which they occur.

To these diversifying influences must be added the effect of
warm up-valley winds that precede the regular afternoon snow
squalls and that nielt the latest fall of snow to exceptionally high
elevations on both the valley floor and the spurs against which
they impinge. The influence of the warmer air current is notably
confined to the heads of those master valleys that run do^vn the
wind, as in the valley heading at the first pass, Cordillera Vilca-
pampa, and at the heads of the many valleys terminating at the
passes of the Maritime Cordillera. Elsewhere the winds are dis-
sipated in complex systems of minor valleys and their effect is
too well distributed to be recognized.

It is clear from the conditions of the problem as outlined on
preceding pages that the amount of canting may be expressed in
feet of difference of the snowline on opposite sides of a range or

280

THE ANDES OF SOUTHERN PERU

in degrees. The former method has, heretofore, been employed.
It is proposed that this method should be abolished and degrees
substituted, on the following grounds : Let A and B, Fig. 190, rep-
resent two mountain masses of unequal area and unequal eleva-
tion. Let the opposite ends of the snowlines of both figures lie
1,000 feet apart as between the windward and leeward sides of a

broad cordillera (A), or as

between the relatively sun-
nier and relatively shadier
slopes of individual moun-
tains or narrow ranges in
high latitudes or high alti-
tudes (B). With increasing
elevation there is increasing
contrast between tempera-
tures in sunshine and in
shade, hence a greater de-
gree of canting (B). Tend-
ing toward a still greater
degree of contrast is the ef-
fect of the differences in the
amounts of snowy precipita-
tion, whicli are always more
marked on an isolated and
lofty mountain summit than
upon a broad mountain
mass (1) because in the
former there is a very re-
stricted area where snow

Fig. 185 — Glacial features in the Peru-
vian Andes near Arcquipa. Sketched from a
railway train, July, 1911. The horizontal
broken lines represent the lower limit of light
snow during late June, 1011. There is a fine
succession of moraines in U-shaped valleys in
all the mountains of the Aroquipa region. A
represents a part of Chacchani northwest of
Arequi|)a; li is looking south by east at Hie
northwest end of Chachani near Pampa tic
Arrieros; C also shows the northwest end of
Oiacehani from a more distant point.

may accumulate, and (2)
because witli increase of elevation there is a rapid and differential
decrease in botli llic rate of adia])atic cooling and the amount of
water vapor; liciicc llio snow producing forces are more quickly
dissipated.

Furthermore, Ilic Icc'wnrd side of a hifty monnlain not only
receives much less snow pidpoilion.illy ili;m ilic leeward side of

is^f^^.

Fig. 186.

-.-jj^.^ ♦

Fig. 1S7.

Fig. 186 — Canted snowline in the Cordillira Vilcapampa between Arma and
Choquetird. Looking east from 13,500 feet.

Fig. 187 — Glacial topograpliy between Lambrama and Antabamba in the Central
Ranges. A recent fall of snow covers tlie foreground. The glaciers are now almost
extinct and their action is confined to the deepening and steepening of the cirques at
the valley heads.

Fici. 188.

Ik; ISO.

I'm;. 1;sH- — .\s\ iiiniit ri<;il pciiks in (lie (Viitnil l{;iii;;rs hctwcrii A ii( :ili:iiiili:i ;m<l
t,iiiiil)niiiiii. 'I'lic >'ii(isv-lillc(l liollows in llic plKitn^iapli, fucc ;i\v;iy troni I lie sun — tliiit
i-. soiilli — iiiid linvc i-ftainrd simw siiici- (lie ;,'liH'i:il rpmli; wliilr llir iinitlicrn slopes
jin- snow-free. 'I'liere is no line ^'liuial ice jind tin- ciinl inind <ir(|iic recession is dne
to niviition

I'M. )H!» Claeial lopo^rnipliy north nf the divide on (lie seventy tiiird meridian,
M.iniiiiK < ordilleru. Loukin^j downstream at an ili\ation <if Kij.JUO feet (.l.O:}!) m.).

GLACIAL FEATURES 281

a lower mountain, but also loses it faster on account of the
smaller extent of surface upon which it is disposed and the pro-
portionally larger extent of counteractive, snow-free surface
about it. Among the volcanoes of Ecuador are many that show
differences of 500 feet in snowline elevation on windward and lee-
ward (east) slopes and some, as for example Chimborazo, that
exhibit differences of 1,000 feet. The latter figure also expresses

looo'.^'r.rx cobradient

Fig. 190 — To illustrate the difference in the degree of canting of the snowline on
large and on small mountain masses.

the differences in the broad Cordillera Vilcapampa and in the
Maritime Cordillera, though the rate of canting as expressed in
degrees is much greater in the case of the western mountains.

The advantages of the proposed method of indicating the de-
gree of canting of the snowline lie in the possibility thus afforded
of ultimately separating and expressing quantitatively the vari-
ous factors that affect the position of the line. In the Cordillera
Vilcapampa, for example, the dominant canting force is the dif-
ference between sun and shade temperatures, while in the vol-
canoes of Ecuador, where symmetrical volcanoes, almost on the
equator, have equal insolation on all aspects and the temperature
contrasts are reduced to a minimum — the differences are owing
chiefly to varying exposure to the winds. The elusive factors in
the comparison are related to the differences in area and in ele-
vation.

The value of arriving finally at close snowline analyses grows
out of (1) the possibility of snowline changes in short cycles and
(2) uncertainty of arriving by existing methods at the snowline
of the glacial period, whose importance is fundamental in refined
physiographic studies in glaciated regions with a complex topog-
raphy. To show the application of the latter point we shall now

282 THE ANDES OF SOUTHERN PERU

attempt to determine the snowline of the glacial period in the belt
of country along the route of the Expedition.

In the group of peaks sho\\Ti in Fig. 188 between Lambrama
and Antabamba, the elevation of the snowline varies from 16,000
to 17,000 feet (4,880-5,180 m.), depending on the topography and
the exposure. The determination of the limit of perpetual snow
was here, as elsewhere along the seventy-third meridian, based
upon evidences of nivation. It will be observed in Fig. 191 that
just under the snow banks to the left of the center are streams of
rock waste which head in the snow. Their size is roughly propor-
tional to the size of the snow banks, and, furthermore, they are not
found on snow-free slopes. From these facts it is concluded that
they represent the waste products of snow erosion or nivation,
just as the hollows in which the snow lies represent tlje topo-
graphic products of nivation. On account of the seasonal and an-
nual variation in precipitation and temperature — hence in the ele-
vation of the snowline — it is often difficult to make a correct snow-
line observation based upon depth and apparent permanence.
Different observers report great changes in the snowline in short
intervals, changes not explained by instrumental variations, since
they are referred to topographic features. It appears to be im-
possible to rely upon present records for small changes possibly
related to minor climatic cycles because of a lack of standardiza-
tion of observations.

Nothing in the world soems simpler at first sight than an ob-
servation on the elevation of the snowline. Yet it can be demon-
strated that large numbers of obscn^ers have merely noted the
position of temporary snow. It is strongly urged that evidences
of nivation servo henceforth as proof of permanent snow and that
photographic records be kept for comparison. In this way meas-
urements of changes in the level of the snowline may bo accurately
made and the snow cover used as a climatic gauge.

Farther west in the Maritime Cordillera, the snowline rises to
18,000 feet on the northern slopes of the mountains and to 17,000
foot on the southern slopes. Tlio top of the pass above Cotahuasi,
17,600 feet (5,360 m.), was snow-free in October, 1911, but the

^^^^

GLACIAL FEATURES 283

snow extended 500 feet lower on the southern slope. The degree
of canting is extraordinary at this point, single volcanoes only
1,500 to 2,000 feet above the general level and with bases but a
few miles in circumference exhibit a thousand feet of difference
in the snowline upon northern and southern aspects. This
is to be attributed no less to the extreme elevation of the snow
(and, therefore, stronger contrasts of shade and sun tempera-
tures) than to tl e extreme aridity of the region and the high day-
time temperatures. The aridity is a factor, since heavy snowfall
means a lengthening of the period of precipitation in which a
cloud cover shuts out the sun and a shortening of the period of
insolation and melting.

Contrasts between shade and sun temperatures increase with
altitude but their effects also increase in time. Of two volcanoes
of equal size and both 20,000 feet above sea level, that one will
show the greater degree of canting that is longer exposed to the
sun. The high daytime temperature is a factor, since it tends to
remove the thinnest snow, which also falls in this case on the side
receiving the greatest amount of heat from the sun. The high
daytime temperature is phenomenal in this region, and is owing
to the great extent of snow-free land at high elevations and yet
below the snowline, and to the general absence of clouds and the
thinness of vegetation.

On approach to the western coast the snowline descends again
to 17,500 feet on Coropuna. There, are three chief reasons for
this condition. First, the well-watered Majes Valley is deeply
incised almost to the foot of Coropuna, above Chuquibamba, and
gives the daily strong sea breeze easy access to the mountain.
Second, the Coast Eange is not only low at the mouth of the Majes
Valley, but also is cut squarely across by the valley itself, so that
heavy fogs and cloud sweep inland nightly and at times completely
cover both valley and desert for an hour after sunrise. Although
these yield no moisture to the desert or the valley floor except
such as is mechanically collected, yet they do increase the precipi-
tation upon the higher elevations at the valley head.

A third factor is the size of Coropuna itself. The mountain

284 THE ANDES OF SOUTHERN PERU

is not a simple volcano but a composite cone with five main sum-
mits reaching well above the snowline, the highest to an elevation
of 21,703 feet (6,615 m.). It measures about 20 miles (32 km.) in
circumference at the snowline and 45 miles (72 km.) at its base
(measuring at the foot of the steeper portion), and stands upon
a great tributary lava plateau from 15,000 to 17,000 feet above
sea level. Compared wdth El Misti, at Arequipa, its volume is
three times as great, its height two thousand feet more, and its
access to ocean winds at least thirty per cent more favorable. El
Misti, 19,200 feet (5,855 m.) has snow down as far as 16,000 feet
in the wet season and rarely to 14,000 feet, though by sunset a
fall of snow may almost disappear whose lower limit at sunrise
was 16,000 feet. Snow may accumulate several thousand feet be-
low the summit during the wet season, and in such quantities as
to require almost the whole of the ensuing dry season (March to
December) for its melting. Northward of El Misti is the massive
and extended range, Chachani, 20,000 feet (6,100 m.) high; on the
opposite side is the shorter range called Pichu-Pichu. Snow lies
throughout the year on both these ranges, but in exceptional sea-
sons it nearly disappears from Chachani and wholly disappears
from Pichu-Pichu, so that the snowline then rises to 20,000 feet.
It is considered that the mean of a series of years would give a
value between 17,000 and 18,000 feet for the snowline on all the
great mountains of the Arequipa region.' This would, however, in-
clude what is known to be temporary snow; the limit of '*per-
Ipetual" snow, or the true snowline, appears to lie about 19,000
feet on Chachani and above El Misti, say 19,500 feet. It is also
above the crest of Pichu-Pichu. The snowline, therefore, appears
to rise a thousand feet from Coropuna to El Misti, owing chiefly
I to the poorer exposure of the latter to the sources of snoAvy pre-
cipitation.

It may also be noted that the effect of the easy access of the
ocean winds in the Coropuna region is also seen in the increasing
amount of vegetation which appears in the most favorable situa-

• R. T. ■Railoy, Ponivinn TNTctoornloRy, 1888-1890. Ann. Astron. Obscrv. of Har-
vard Coll., Vol. 30, rt. I, 1899, pp. 1-3.

GLACIAL FEATURES 285

tions. Thus, along the Salamanca trail only a few miles from the
base of Coropuna are a few square kilometers of quenigo wood-
land generally found in the cloud belt at high altitudes; for ex-
ample, at 14,000 feet above Lambrama and at 9,000 feet on the
slope below Incahuasi, east of Pasaje. The greater part of the
growth is disposed over hill slopes and on low ridges and valley
walls. It is, therefore, clearly unrelated as a whole to the greater
amount of ground-water with which a part is associated, as along
the valley floors of the streams that head in the belt of perpetual
snow. The appearance of this growth is striking after days of
travel over the barren, clinkery lava plateau to eastward that has
a less favorable exposure. The quenigo forest, so-called, is of
the greatest economic value in a land so desolate as the vast arid
and semi-arid mountain of western Peru. Every passing traveler
lays in a stock of fire-wood as he rests his beasts at noonday; and
long journeys are made to these curious woodlands from both
Salamanca and Chuquibamba to gather fuel for the people of the
towns.

NIV^ATION"

The process of nivation, or snow erosion, does not ahvays pro-
duce visible effects. It may be so feeble as to make no impression
upon very resistant rock where the snow-fall is light and the
declivity low. Ablation may in such a case account for almost the
whole of the snow removed. On strong and topographically
varied slopes where the snow is concentrated in headwater alcoves,
there is a more pronounced downward movement of the snow
masses with more prominent effects both of erosion beneath the
snow and of accumulation at the border of the snow. In such
cases the limit of perpetual snow may be almost as definitely
known as the limit of a glacier. Like glaciers these more power-
ful snow masses change their limits in response to regional
changes in precipitation, temperature, or both. It would at first
sight appear impossible to distinguish between these changes
through the results of nivation. Yet in at least a few cases it may
be as readily determined as the past limits of glaciers are inferred

286 THE ANDES OF SOUTHERN PERU

from the terminal moraines, still intact, that cross the valley
floors far below the present limits of the ice.

In discussing the process of nivation it is necessary to assume
a sliding movement on the part of the snow, though it is a condi-
tion in Matthes ' original problem in which the nivation idea was
introduced that the snow masses remain stationary. It is be-
lieved, however, that Matthes' valuable observations and conclu-
sions really involve but half the problem of nivation; or at the
most but one of two phases of it. He has adequately sho^^m the
manner in which that phase of nivation is expressed which we find
at the border of the snow. Of the action beneath the snow he
says merely : ' ' Owing to the frequent oscillations of the edge and
the successive exposure of the different parts of the site to frost
action, the area thus affected will have no well-defined boundaries.
The more accentuated slopes will pass insensibly into the flatter
ones, and the general tendency will be to give the drift site a cross
section of smoothly curved outline and ordinarily concave. ' ' *

From observations on the effects of nivation in valleys, Matthes
further concludes that "on a grade of about 12 per cent . . .
neve must attain a thickness of at least 125 feet in order that it
may have motion,"' though as a result of the different line of
observations Hobbs concludes ' that a somewhat greater thickness
is required.

The snow cover in tropical mountains offers a number of solid
advantages in this connection. Its limits, especially on the Cordil-
lera Vilcapampa, on the eastern border of the Andes, are subject
to small seasonal oscillations and the edge of the ''perpetual"
snow is easily determined. Furthermore, it is known from the
comparatively ''fixed quality of tropical climate," as Humboldt
put it, that the variations of the snowline in a period of years do
not exceed rather narrow limits. In mid-latitudes on the con-
trary there is an extraordinary shifting of the margin of the snow

* F. E. MatthoB, Clncinl Sculpture of tlio Bighorn Mountainn, Wyoming, Twentieth
Ann. Kept. U. S. Cool. Surv., 1S!)!)-1J)00, Pt. 2, p. 181.

' Idem, p. ino.

• \V, H. Hobbs, Clinractcristics of Kxisling GlacierH, lUll, p. 22.

Fig. 191.

Fig. 192.

Fig 191 — The "pocked" surface characteristically developed in the zone of light
nivation. Compare with Fig. 194, showing the effects of heavy nivation.

Fig. 192 — Steep cirque walls and valleys head in the Central Ranges between
Lambrama and Chuquibambilla. The snow is here a vigorous agent in transporting
talus material and soil from all the upper slopes down to the foot of the cirque wall.

Fig. 193.

\'\i

i:i

Fio. HJ.'J — I'antii Moiiiitiiin and it-i jjluciir system. 'I'lic lalns-covcrod mass in the
cpntor (]{) is a t<TMiiniil moraiiii- t«)i)pc(l li.v tlic dirt-slaincd j^lacicr tliat descends
from tlic orcst. Tin- Hopiiiatc f^Iaricrs wfic formerly united to form a Inipe ice tongne
that truncated tlie lat<Tal s]MirH and flattened tlie valley floor. One of its former
stages is sliown liy tlie terminal moraine in (lie middle dislaiicc, I)reiieiied liy a stream,
and impounding a lake not visihle from tliis jioiiit of \ iew.

I'll; IMJ— Heeessed soulliern slopes of volriuioes w liose norl liern slopes are prac-
tically williout glacial modifieatioiiH. Summit of tlic lava plateau, Marifime Cordillera,
Aveatern Peru, between Antahandta and Cotaliuasi.

GLACIAL FEATURES 287-

cover, and a correspondingly wide distribution of the feeble ef-
fects of nivation.

Test cases are presented in Figs. 191, 192, and 193, Cordillera
Vilcapampa, for the determination of the fact of the movement
of the snow long before it has reached the thickness Matthes or
Hobbs believes necessary for a movement of translation to begin.
Fig. 191 shows snow masses occupying pockets on the slope of a
ridge that was never covered with ice. Past glacial action wdth
its complicating effects is, therefore, excluded and we have to deal
with snow action pure and simple. The pre-glacial surface with
smoothly contoured slopes is recessed in a noteworthy way from
the ridge crest to the snowline of the glacial period at least a thou-
sand feet lower. The recesses of the figure are peculiar in that
not even the largest of them involve the entire surface from top
to bottom ; they are of small size and are scattered over the entire
slope. This is believed to be due to the fact that they represent
the limits of variations of the snowline in short cycles. Below
them as far as the snowline of the glacial period are larger re-
cesses, some of which are terminated by masses of waste as exten-
sive as the neighboring moraines, but disposed in irregular scal-
lops along the borders of the ridges or mountain slopes in which
the recesses have been found.

The material accumulated at the lower limit of the snow cover
of the glacial period was derived from two sources: (1) from
slopes and cliffs overlooking the snow, (2) from beneath the snow
by a process akin to ice plucking and abrasion. The first process
is well known and resembles the shedding of waste upon a valley
glacier or a neve field from the bordering cliffs and slopes. Ma-
terial derived in this manner in many places rolls down a long
incline of snow and comes to rest at the foot of it as a fringe of
talus. The snow is in this case but a substitute for a normal mass
of talus. The second process produces its most clearly recogniza-
ble effects on slopes exceeding a declivity of 20° ; and upon 30°
and 40° slopes its action is as well-defined as true glacial action
which it imitates. It appears to operate in its simplest form as
if independent of the mass of the snow, small and large snow

288 THE ANDES OF SOUTHERN PERU

patches showing essentially the same results. This is the reverse
of Matthes' conclusion, since he says that though the minimum
thickness ''must vary inversely with the percentage of the grade,"
''the influence of the grade is inconsiderable," and that the law
of variation must depend upon additional observation.''

Let us examine a number of details and the argument based
upon them and see if it is not possible to frame a satisfactory law
of variation.

In Fig. 193 the chief conditions of the problem are set forth.
Forward from the right-hand peak are snow masses descending
to the head of a talus {A) whose outlines are clearly defined by
freshly fallen snow. At (B) is a glacier whose tributaries descend
the middle and left slopes of the picture after making a descent
from slopes several thousand feet higher and not visible in this
view. The line beneath the glacier marks the top of the moraine
it has built up. Moraines farther down valley show a former
greater extent of the glacier. Clearly the talus material at (^)
was accumulated after the ice had retreated to its present posi-
tion. It will be readily seen from an inspection of the photograph
that the total amount of material at {A) is an appreciable fraction
of that in the moraine. The ratio appears to be about 1 : 8 or 1 : 10.
I have estimated that the total area of snow-free surface about
the snowfields of the one is to that of the other as 2:3. The
gradients are roughly equivalent, but the volume of snow in the
one case is but a small fraction of that in the other. It will be
seen that the snow masses have recessed the mountain slopes at A
and formed deep hollows and that the hollowing action appears to
be most effective where the snow is thickest.

Summarizing, we note first, that the roughly equivalent factors
are gradient and amount of snow-free surface; second, that the
unequal factors are (a) accumulated waste, (b) degree of recess-
ing, and (c) the degree of compacting of snow into ice and a cor-
responding difference in the character of the glacial agent, and
(d) the extent of the snow cover. The direct and important

* Op. cit., p. 286. Reference on p. 190,

GLACIAL FEATURES 289

relation of the first two unequal factors to the third scarcely need
be pointed out.

We have then an inequality in amount of accumulated material
to be explained by either an inequality in the extent of the snow
and therefore an inequality of snow action, or an inequality due
to the presence of ice in one valley and not in the other, or by
both. It is at once clear that if ice is absent above (A) and the
mountain slopes are recessed that snow action is responsible for
it. It is also recognized that whatever rate of denudation be as-
signed to the snow-free surfaces this rate must be exceeded by
the rate of snow action, else the inequalities of slope would be
decreased rather than increased. The accumulated material at
(A) is, therefore, partly but not chiefly due to denudation of snow-
free surfaces. It is due chiefly to erosion beneath the snow. Nor
can it be argued that the hollows now occupied by snow were
formed at some past time when ice not snow lay in them. They
are not ice-made hollows for they are on a steep spur above the
limits of ice action even in the glacial period. Any past action is,
therefore, represented here in kind by present action, though there
would be differences in degree because the heavier snows of the
past were displaced by the lighter snows of today.

While it appears that the case presents clear proof of degrada-
tion by snow it is not so clear how^ these results were accomplished.
Eeal abrasion on a large scale as in bowlder-shod glaciers is
ruled out, since glacial striae are wholly absent from nivated sur-
faces according to both Matthes' observations and my own. Yetl
all nivated surfaces have very distinctive qualities, delicately or-,
ganized slopes which show a marked change from any original
condition related to water-carving. In the absence of striae, the
general absence of all but a thin coating of waste even in rock hol-
lows, and the accumulation of waste up to bowlders in size at the
lower edge of the nivated zone, I conclude that compacted snow
or neve of sufficient thickness and gradient may actually pluck
rock outcrops in the same manner though not at the rate which
ice exhibits. That the products of nivation may be bowlders as
well as fine mud would seem clearly to follow increase in effective:

290 THE ANDES OF SOUTHERN PERU

ness, due to increase in amount of the accumulated snow; that
bowlders are actually transported by snow is also sho^^^l by their
presence on the lower margins of nivated tracts.

Our argument may be made clearer by reference to the ob-
served action of snow in a particular valley. Snow is shed from
the higher, steeper slopes to the lower slopes and eventually ac-
cumulates to a marked degree on the bottoms of the depressions,
whence it is avalanched do^Ti valley over a series of irregular
steps on the valley floor. An avalanche tal^es place through the
breaking of a section of snow just as an iceberg breaks off the
end of a tide-water glacier. Evidently there must be pressure
from behind which crowds the snow forward and precipitates it
to a lower level.

As a snow mass falls it not only becomes more consolidated,
beginning at the plane of impact, but also gives a shock to the
mass upon which it falls that either starts it in motion or acceler-
ates its rate of motion. The action must therefore be accom-
panied by a drag upon the floor and if the rock be close-jointed
and the blocks, defined by the joint planes, small enough, they will
be transported. Since snow is not so compact as ice and permits
included blocks easily to adjust themselves to new resistances, we
should expect the detached blocks included in the snow to change
their position constantly and to form irregular scratches, but not
parallel strice of the sort confidently attributed to stone-shod ice.

It is to the plasticity of snow that we may look for an ex-
planation of the smooth-contoured appearance of the landscape in
the foreground of Fig. 135. The smoothly curved lines are best
developed where the entire surface was covered with snow, as in
mid-elevations in the larger snowfields. At liigher elevations,
where the relief is sharper, the snow is sliod from the steeper
declivities and collected in tlio minor basins and valley heads,
where its action tends to sniootli a floor of limited area, while
snow-free surfaces retain all llicir original irrogularitios of form
or are actually sharpened.

The degree of offectivencss of snow and neve action may be
estimated from the reversed slopes now marked by ponds or small

GLACIAL FEATURES 291

marshy tracts scattered throughout the former neve fields, and
the many niched hollows. They are developed above Pampaconas
in an admirable manner, though their most perfect and general
development is in the summit belt of the Cordillera Vilcapampa
between Arma and Choquetira, Fig. 135. It is notable in all cases
where nivation was associated with the work of valley glaciers
that the rounded nivated slopes break rather sharply with the
steep slopes that define an inner valley, w^hose form takes on the
flat floor and under-cut marginal walls normal to valley glaciation.

A classification of numerous observations in the Cordillera
Vilcapampa and in the Maritime Cordillera between Lambrama
and Antabamba may now be presented as the basis for a tenta-
tive expression of the law of variation respecting snow motion.
The statement of the law should be prefaced by the remark that
thorough checking is required under a wider range of conditions
before we accept the law as final. Near the lower border of the
snow where rain and hail and alternate freezing and thawing take
place, the snow is compacted even though but fifteen to twenty feet
thick, and appears to have a down-grade movement and to exer-
cise a slight drag upon its floor when the gradient does not fall
below 20°. Distinct evidences of nivation were observed on slopes
with a declivity of 5° near summit areas of past glacial action,
where the snow did not have an opportunity to be alternately
frozen and thawed.

The thickness of the former snow cover could, however, not be
accurately determined, but was estimated from the topographic
surroundings to have been at least several hundred feet. Upon
a 40° slope a snow mass 50 feet thick was observed to be break-
ing off at a cliff-face along the entire cross-section as if impelled
forward by thrust, and to be carrying a small amount of waste
— enough distinctly to discolor the lowermost layers — which was
shed upon the snowy masses below. With increase in the degree
of compactness of the snow at successively lower elevations along
a line of snow discharge, gradients do^\Ti to 25° were still observed
to carry strongly crevassed, waste-laden snow down to the melt-
ing border. It appeared from the clear evidences of vigorous

292 THE ANDES OF SOUTHERN PERU

action — the accumulation of waste, the strong crevassing, the
stream-like character of the discharging snow, and the pro-
nounced topographic depression in which it lay — that much flatter
gradients would serve, possibly not more than 15°, for a snow
mass 150 feet wide, 30 to 40 feet thick, and serving as the out-
let for a set of tributary slopes about a square mile in area
and with declivities ranging from small precipices to slopes of 30°.

We may say, therefore, that the factors affecting the rate of
motion are (1) thickness, (2) degree of compactness, (3) diurnal
temperature changes, and (4) gradient. Among these, diurnal
temperature changes operate indirectly by making the snow more
compact and also by inducing motion directly. At higher eleva-
tions above the snowline, temperature changes play a decreas-
ingiy important part. The thickness required varies inversely as
the gradient, and upon a 20° slope is 20 feet for wet and compact
snow subjected to alternate freezing and thawing. For dry snow
masses above the zone of effective diurnal temperature changes,
an increasing gradient is required. With a gradient of 40°, less
than 50 feet of snow will move en masse if moderately compacted
under its o^\^l weight; if further compacted by impact of falling
masses from above, the required thickness may diminish to 40
feet and the required declivity to 15°. The gradient may decrease
to 0° or actually be reversed and motion still continue provided
the compacting snow approach true neve or even glacier ice as a
limit.

From the sharp topographic break between the truly glaciated
portions of the valley in regions subjected to temporary glacia-
tion, it is concluded that the eroding power of the moving mass
is suddenly increased at the point where neve is finally trans-
formed into true ice. This transformation must be assumed to
take place suddenly to account for so sudden a change of function
as the topograpliic break re(]uiros. Below the point at wliich the
transformation occurs the motion takes place under a new set of
conditions whose laws have already been formulated by students
of glaciolog>\

The foregoing readings of gradient and depth of snow are

GLACIAL FEATURES

293

typical of a large number which were made in the Peruvian Andes
and which have served as the basis of Fig. 195. It mil be observed
that between 15° and 20° there is a marked change of function and
again between +5° and — 5° declivity, giving a double reversed
curve. The meaning of the change between 15° and 20° is inferred
to be that, with gradients over 20°, snow cannot wholly resist

300

250

ZOO

150

100

CURVE OF SNOW MOTION

- 50 0" 5° 10" 15° 20° 25° 30° 35° 40"

Fig. 195 — Curve of snow motion. Based on many observations of snow motion to
show minimum thickness of snow required to move on a given gradient. Figures on
the left represent thickness of snow in feet. The degrees represent the gradient of the
surface. The gradients have been run in sequence down to 0° for the sake of com-
pleting the accompanying discussion. Obviously no glacially unmodified valley in a
region of mountainous relief would start with so low a gradient, though glacial action
would soon bring it into existence. Between -f5° and — 5° the curve is based on the
gradients of nivated surfaces.

gravity in the presence of diurnal temperature changes across the
freezing point and occasional snow or hail storms. With increase
of thickness compacting appears to progress so rapidly as to
permit the transfer of thrust for short distances before absorp-
tion of thrust takes place in the displaced snow. At 250 feet
thorough compacting appears to take place, enabling the snow to
move out under its own weight on even the faintest slopes ; while,

294 THE ANDES OF SOUTHERN PERU

with a thickness still greater, the resulting neve may actually be
forced up slight inclines whose declivity appears to approach 5°
as a limit. I have nowhere been able to find in truly nivated areas
reversed curves exceeding 5°, though it should be added that de-
pressions whose leeward slopes were reversed to 2° and 3° are
fairly common. If the curve were continued we should undoubt-
edly find it again turning to the left at the point where the thick-
ness of the snow results in the transformation of snow to ice.
From the sharp topographic break observed to occur in a narrow
belt between the neve and the ice, it is inferred that the erosive
power of the neve is to that of the ice as 2:4 or 1:5 for equal
areas; and that reversed slopes of a declivity of 10° to 15° may
be formed by glaciers is well kno^vn. Precisely what thickness of
snow or neve is necessary and what physical conditions effect its
transformation into ice are problems not included in the main
theme of this chapter.

It is important that the proposed curve of snow motion under
minimum conditions be tested under a large variety of circum-
stances. It may possibly be found that each climatic region re-
quires its special modifications. In tropical mountains the sud-
den alternations of freezing and thawing may effect such a high
degree of compactness in the snow that lower minimum gradients
are required than in the case of mid-latitude mountains where
the perpetual snow of the high and cold situations is compacted
through its own weight. Observations of the character introduced
here are still unattainable, however. It is hoped that they will
rapidly increase as their significance becomes apparent; and that
they have high significance the striking nature of the curve of
motion seems clearly to establish.

BEnnSCHRUNDS AND CIRQUES

The facts brought out by the curve of snow-motion (Fig. ]95)
have an immediate bearing on the development of cirques, whose
precise mode of origin and development have long been in doubt.
Without reviewing ilic arguments upon wliicli llic various hy-
potheses rest, we shall begin at once with the strongest explana-

GLACIAL FEATURES 295

tion — W. D. Johnson's famous bergschrund hypothesis. The
critical condition of this hypothesis is the diurnal migration
across the freezing point of the air temperature at the bottom of
the schrund. Alternate freezing and thawing of the water in the
joints of the rock to which the schrund leads, exercise a quarry-
ing effect upon the rock and, since this effect is assumed to take
place at the foot of the cirque, the result is a steady retreat of
the steep cirque wall through basal sapping.

While Johnson's hypothesis has gained wide acceptance and
is by many regarded as the final solution of the cirque problem
it has several weaknesses in its present form. In fact, I believe
it is but one of two factors of equal importance. In the first
place, as A. C. Andrews ^ has pointed out, it is extremely improb-
able that the bergschrund of glacial times under the conditions of
a greater volume of snow could have penetrated to bedrock at the
base of the cirque where the present change of slope takes place.
In the second place, the assumption is untenable that the berg-
schrund in all cases reaches to or anywhere near the foot of the
cirque w^all. A third condition outside the hypothesis and con-
tradictory to it is the absence of a bergschrund in snowfields at
many valleys heads where cirques are w^ell developed!

Johnson himself called attention to the slender basis of ob-
servation upon which his conclusions rest. In spite of his own
caution with respect to the use of his meager data, his hypothesis
has been applied in an entirely too confident manner to all kinds
of cirques under all kinds of conditions. Though Johnson de-
scended an open bergschrund to a rock floor upon which ice rested,
his observations raise a number of proper questions as to the
application of these valuable data: How long are bergschrunds
open? How often are they open? Do they everjnvhere open to
the foot of the cirque wall? Are they present for even a part of
the year in all well-developed cirques? Let us suppose that it
is possible to find many cirques filled with snow, not ice, sur-
rounded by truly precipitous walls and vnth. an absence of berg-

* Corrosion of Gravity Streams with Application of the Ice Flood Hypothesis,
Journ. and Proc. of the Royal Society of N. S. Wales, Vol. 43, 1909, p. 286.

296 THE ANDES OF SOUTHERN PERU

schrunds, how shall we explain the topographic depressions ex-
cavated underneath the snowf If cirque formation can be shown
to take place without concentrated frost action at the foot of the
bergschrund, then is the bergschrund not a secondary rather than
a primary factor! And must we not further conclude that when
present it but hastens an action which is common to all snow-cov-
ered recesses'?

It is a pleasure to say that we may soon have a restatement of
the cirque problem from the father of the bergschrund idea. The
argument in this chapter was presented orally
to him after he had remarked that he was glad
to know that some one was finding fault mth his
hypothesis. ''For," he said, with admirable
spirit, '' I am about to make a most violent
attack upon the so-called Johnson li}T)othesis."
I wish to say frankly that while he regards
Fig. 19G— Roia- ^^^ following argument as a valid addition to

tion of cirque wall to o <=>

trough's end at the the problem, he does not think that it solves
head of a glaciated ^^^ problem. There are many of us who will

valley. The ratio -^

of the inner to the read his ucw explanation with the deepest

outer radiu3 is 1:4. interest.

We shall begin with the familiar fact that many valleys, now
without perpetual snow, formerly contained glaciers from 500 to
1,000 feet thick and that their snowfields were of wide extent and
great depth. At the head of a given valley where the snow is
crowded into a small cross-section it is compacted and suffers a re-
duction in its volume. At first nine times the volume of ice, the
gradually compacting neve approaches the volume of ice as a limit.
At the foot of the circiue wall we may fairly assume in the absence
of direct observations, a volume reduction of oue-half due to com-
pacting. r.n< Ihis is offset in the case of a well-developed cirque
l)y vohiiiic increases due to the convergence of the snow from the
surrounding slopes, as shown in Fig. 19G. Taking a typical
cirque from a point above Vilcabamba pueblo I find that the
radius of tlie trough's end is to the radius of the upper wall
of the cirque as 1:4; and since the corresponding surfaces are

GLACIAL FEATURES

297

to one another as the squares of their similar dimensions we
have 1:4 or 1 : 16 as the ratio of their snow areas. If no com-
pacting took place, then to acconunodate all the snow in the glacial
trough would require an increase in thickness in the ratio of
1:4. If the snow were compacted to half its original volume then
the ratio would be 1:2. Now, since the volume ratio of ice to

Fig. 197 — Mode of cirque formation. Taking the facts of snow deptli represented
in the curve, Fig. 195, and transposing them over a profile (the heavy line) which
ranges from 0° declivity to 50°, we find that the greatest excess of snow occurs
roughly in the center. Here ice will first form at the bottom of the snow in the
advancing hcmicycle of glaciation, and here it will linger longest in the hemicycle
of retreat. Here also there will be the greatest mass of nev6. All of these factors
are self-stimulating and will increase in time until the floor of the cirque is flattened
or depressed sufficiently to offset through uphill ice-flow the augmented forces of
erosion. The effects of self-stimulation are shown by "snow increase"; the ice shoe
at the bottom of the cirque is expressed by " ice factor." The form accompanying both
these terms is merely suggestive. The top of "excess snow" has a gradient char-
acteristic of the surface of snow fields. A preglacial gradient of 0° is not permissible,
but I have introduced it to complete the discussion in the text and to illustrate the
flat floor of a cirque. A bergschrund is not required for any stage of this process,
though the process is hastened wherever bergschrunds exist.

snow is 1 : 9 and the thickness of the ice down valley is, say 400
feet, the equivalent of loose snow at the foot of the cirque must
be more than 1 : 4 over 1:9 or more than two and one-quarter
times thicker, or 400 feet thick; and would give a pressure of
(900 -^ 10) X 62.5 pounds, or 5,625 pounds, or a little less than
three tons per square foot. Since a pressure of 2,500 pounds per
square foot will convert snow into ice at freezing temperature, it

298 THE ANDES OF SOUTHERN PERU

is clear that ice and not snow was tlie state at the bottom of the
mass in glacial times. Further, between the surface of the snow
and the surface of the bottom layer of the ice there must have
been every gradation between loose snow and firm ice, with the
result that a thickness much less than 900 feet must be assumed.
Precisely what thickness would be found at the foot of the cirque
wall is unkno"^Ti. But granting a thickness of 400 feet of ice an
additional 300 feet for neve and snow would raise the total to 700
feet.

The application of the facts in the above paragraph is clearly
seen when we refer to Fig. 197. The curve of snow motion of Fig.
195 is applied to an unglaciated mountain valley. Taking a
normal snow surface and filling the valley head it is seen that
the excess of snow depth over the amount required to give motion
is a measure at various points in the valley head and at different
gradients of the erosive force of the snow. It is strikingly con-
centrated on the 15°-20° gradient which is precisely where the so-
called process of basal sapping is most marked. If long continued
the process will lead to the developing of a typical cirque for it is
a process that is self-stimulating. The more the valley is changed
in form the more it tends to change still further in form because
of deepening snowfields until cliffed pimiacles and matterhorns
result.

By further reference to the figure it is clear that a schrund
350 feet deep could not exist on a cirque wall with a declivity of
even 20° without being closed by flow, unless we grant more rapid
flow below the crevasse. In the case of a glacier flowing over a
nearly flat bed away from the cirque it is difficult to conceive of a
rate of flow greater than that of snow and neve on the steep lower
portion of the cirque wall, when movement on Hint gradient begins
with snow but 20 feet tliick.

In contrast to this is the view that the schrund line should lie
well up the cirque wall where the snow is comparatively thin and
where there is an api)roach to the lower limits of movement.
The schrund would appear to open whore the bottom material
changes its form, i.e., where it first has its motion accelerated by

GLACIAL FEATURES 299

transformation into neve. In this view the schrund opens not at
the foot of the cirque wall but well above it as in Fig. 198, in
which C represents snow from top to bottom ; B, neve ; and A, ice.
The required conditions are then (1) that the steepening of the
cirque wall from x to y should be effected by sapping originated
at y through the agencies outlined by Johnson; (2) that the steep-
ening from X to y should be effected by sapping originated at x
through the change of the agent from neve to ice with a sudden
change of function; (3) and that the essential unity of the wall
x-y-s be maintained through the erosive power of the neve, which
would tend to offset the formation of a shelf along a horizontal
plane passed through y. The last-named process not only appears
entirely reasonable from the conditions of gradient and depth out-
lined on pp. 296 to 298, but also meets the actual field conditions in
all the cases examined in the Peruvian Andes. This brings up
the second and third of our main considerations, that the berg-
schrund does not always or even in many cases reach the foot of
the cirque wall, and that cirques exist in many cases where berg-
schrunds are totally absent.

It is a striking fact that frost action at the bottom of the
bergschrund has been assumed to be the only effective sapping
force, in spite of the common observation that bergschrunds lie
in general well toward the upper limits of snowfields — so far, in
fact, that their bottoms in general occur several hundred feet
above the cirque floors. Is the cirque under these circumstances
a result of the schrund or is the schrund a result of the cirque?
In what class of cirques do schrunds develop? If cirque develop-
ment in its early stages is not marked by the development of
bergschrunds, then are bergschrunds an essential feature of
cirques in their later stages, however much the sapping process
may be hastened by schrund formation?

Our questions are answered at once by the indisputable facts
that many schrunds occur well toward the upper limit of snow,
and that many cirques exist whose sno^\^elds are not at all broken
by schrunds. It was Avith great surprise that I first noted the
bergschrunds of the Central Andes, especially after becoming

300

THE ANDES OF SOUTHERN PERU

familiar with Jolinson's apparently complete proof of their
genetic relation to the cirques. But it was less surprising to dis-
cover the position of the few observed— high up on the cirque
walls and always near the upper limit of the sno^vfields.

A third fact from regions once glaciated but now snow-free
also combined with the two preceding facts in weakening the whole-
sale application of Johnson's hypothesis. In many headwater
basins the cirque whose wall at a distance seemed a unit was really
broken into two unequal portions; a lower, much grooved and
rounded portion and an upper unglaciated, steep-walled portion.
This condition was most puzzling in view of the accepted explana-
tion of cirque formation, and it was not until the two first-named
facts and the applications of the curves of snow motion were
noted that the meaning of the break on the cirque became clear.

Referring to Fig. 198 we see at
once that the break occurs at y
and means that under favorable
topographic and geologic condi-
tions sapping at y takes place
faster than at x and that the re-
treat of y-z is faster than x-y.
It will be clear that when these
conditions are reversed or sapping at x and at y are equal a
single wall will result. On reference to the literature I find that
Gilbert recently noted this feature and called it the schrundline.^
lie believes that it marks the base of the bergschrund at a late
stage in the excavation of the cirque basin. lie notes further that
the lower less-stoop slope is glacially scoured and that it forms
"a sort of shoulder or terrace."

If all llic structural and topographic conditions were known in
a great xaricfy of gallicring basins wo should iin(l()ul)iodly find
ill llir'in, and not in special forms of ice erosion, an explanation
oi" the various forms assumed by cirques. The limitations in-
herent in a high-altitude field and a limited snow cover prevented

Fig. 198 — Tlie dovclopiiicnt of eirqiu's
Sec text, p. 200, and Fig. 199.

• n. K. Gilbfrt, Syat/^mnlic Asymmetry of Crest Linos in the ITigli Riorra of
California. Jour. Gcol., Vol. 12, 1904, p. 582.

GLACIAL FEATURES 301

me from solving the problem, but it offered sufficient evidence at
least to indicate the probable lines of approach to a solution. For
example it is noteworthy that in all the cases examined the
schrundline was better developed the further glacial erosion had
advanced. So constantly did this generalization check up, that if
at a distance a short valley was observed to end in a cirque, I
knew at once and long before I came to the valley head that a
shoulder below the schrundline did not exist. At the time this
observation was made its significance w^as a mystery, but it repre-
sents a condition so constant that it forms one of the striking
features of the glacial forms in the headwater region.

The meaning of this feature is represented in Fig. 199, in
which three successive stages in cirque development are shoT\Ti.
In A, as displayed in small val-
leys or mountainside alcoves
which were but temporarily oc-
cupied by snow and ice, or as in
all higher valleys during the
earlier stages of the advancing pig 199— Further stages in the de-

hemicycle of glaciation, snow velopmcnt of cirques. See p. 299 and Fig.

collects, a short glacier forms,

and a bergschrund develops. As a result of the concentrated frost
action at the base of the bergschrund a rapid deepening and steep-
ening takes place at a. As long as the depth of snow (or snow and
neve) is slight the bergschrund may remain open. But its existence
at this particular point is endangered as the cirque grows, since the
increasing steepness of the slope results in more rapid snow move-
ment. Greater depth of snow goes hand in hand with increasing
steepness and thus favors the formation of neve and even ice at
the bottom of the moving mass and a constantly accelerated rate
of motion. At the same time the bergschrund should appear
higher up for an independent reason, namely, that it tends to
form between a mass of slight movement and one of greater
movement, which change of function, as already pointed out,
would appear to be controlled by change from snow to neve or
ice on the part of the bottom material.

302 THE ANDES OF SOUTHERN PERU

The first stages in the upward migration of the bergschrund
^vill not effect a marked change from the original profile, since
the converging slopes, the great thickness of neve and ice at this
point, and the steep gradient all favor powerful erosion. When,
however, stage C is reached, and the bergschrund has retreated
to c", a broader terrace results below the schrundline, the gradient
is decreased, the ice and neve (since they represent a constant dis-
charge) are spread over a greater area, hence are thinner, and we
have the cirque taking on a compound character with a lower, less
steep and an upper, precipitous section.

It is clear that a closely jointed and fragile rock might be
quarried by moving ice at c'-c" and the cirque wall extended un-
broken to X; it is equally clear that a homogeneous, unjointed gran-
ite would offer no opportunities for glacial plucking and would
powerfully resist the much slower process of abrasion. Thus
Gilbert ^° observed the schrundline in the granites of the Sierra
Nevada, which are "in large part structureless" and my own ob-
servations show the schrundline well developed in the open-
jointed granites of the Cordillera Vilcapampa and wholly absent
in the volcanoes of the Maritime Cordillera, where ashes and cin-
ders, the late products of volcanic action, form the easily eroded
walls of the steep cones. Somewhere between these extremes —
lack of a variety of observations prevents our saying where — the
resistance and the internal structure of the rock will just permit
a cirque wall to extend from x to c' " of Fig. 199.

A common feature of cirques that finds an explanation in the
proposed hypothesis is the notch that commonly occurs at some
point where a convergence of slopes above the main cirque wall
concentrates snow discharge. It is proposed to call this type the
notched cirque. It is highly significant tliat these notches are
commonly marked by even steeper descents at the point of dis-
charge into tlie main cirque than the remaining portion of the
cirque wall, even when the discharge was from a very small
basin and in the form of snow or at the most neve. The excess of
discharge at a point on the basin rim ought to produce the form

'" Op. cit., p. 300; reft-ronce on p. 582.

GLACIAL FEATURES 303

we find there under the conditions of snow motion outlined in
earlier paragraphs. It is also noteworthy that it is at such a
point of concentrated discharge that crevasses no sooner open than
they are closed by the advancing snow masses. To my mind the
whole action is eminently representative of the action taking
place elsewhere along the cirque wall on a smaller scale.

What seems a good test of the explanation of cirques here
proposed was made in those localities in the Maritime Cordillera,
where large snowbanks but not glaciers affect the form of the
catchment basins. A typical case is showQ in Fig. 201. As in
many other cases we have here a great lava plateau broken fre-
quently by volcanic cones of variable composition. Some are of
lava, others consist of ashes, still others of tuff and lava and
ashes. At lower elevations on the east, as at 16,000 feet betw^een
Antabamba and Iluancarama, evidences of long and powerful
glaciers are both numerous and convincing. But as we rise still
higher the glaciated topography is buried progressively deeper
under the varying products of volcanic action, until finally at the
summit of the lava fields all evidences of glaciation disappear in
the greater part of the country between Huancarama and the
main divide. Nevertheless, the summit forms are in many cases
as significantly altered as if they had been molded by ice. Pre-
cipitous cirque walls surround a snow-filled amphitheater, and
the process of deepening goes forward under one's eyes. No
moraines block the basin outlets, no U-shaped valleys lead for-
ward from them. We have here to do with post-glacial action
pure and simple, the volcanoes having been formed since the close
of the Pleistocene.

Likewise in the pass on the main divide, the perpetual snow
has begun the recessing of the very recent volcanoes bordering
the pass. The products of snow action, muds and sands up to very
coarse gravel, glaciated in texture with an intermingling of
blocks up to six inches in diameter in the steeper places, are col-
lected into considerable masses at the snowline, where they form
broad sheets of waste so boggy as to be impassable except by care-
fully selected routes. No ice action whatever is visible below

304 THE ANDES OF SOUTHERN PERU

the snowline and the snow itself, though wet and compact, is not
underlain by ice. Yet the process of holloT\dng goes forward
visibly and in time will produce serrate forms. In neither case
is there the faintest sign of a bergschrund; the gradients seem
so well adjusted to the thickness and rate of movement of the
snow from point to point that the marginal crack found in many
sno^^'fields is absent.

The absence of bergschrunds is also noteworthy in many locali-
ties where formerly glaciation took place. This is notoriously the
case in the summit zone of the Cordillera Vilcapampa, where the
accumulating snows of the steep cirque walls tumble down hun-
dreds of feet to gather into prodigious snowbanks or to form
neve fields or glaciers. From the converging walls the snowfalls
keep up an intermittent bombardment of the lower central snow
masses. It is safe to say that if by magic a bergschrund could
be opened on the instant, it would be closed almost immediately
by the impetus supplied by the falling snow masses. The explana-
tion appears to be that the thicker snow and neve concentrated at
the bottom of the cirque results in a corresponding concentration
of action and effect; and cirque development goes on without
reference to a bergschrund. The chief attraction of the berg-
schrund hypothesis lies in the concentration of action at the foot
of the cirque wall. But in the thickening of the snow far beyond
the minimum thickness required for motion at the base of the
cirque wall and its change of function with transformation into
neve, we need invoke no otlior agent. If a bergschrund forms, its
action may take place at the foot of the cirque wall or high up on
tlie wall, and yet sapping at tlie foot of the wall continue.

From which we conclude (1) that where frost action occurs at
the bottom of a bergschrund opening to the foot of the cirque wall
it aids in the retreat of tlie wall; (2) tliat a sapping action takes
place at iliis ])()iii1. wlicihci- oi- not a l)orgschrund exists and that
bergschrund action is not a necessary part of cirque formation;
(3) that when a more or less persistent bergschrund opens on the
cirque wall above its foot it tends to develop a schrundline with
a marked terrace below it; (4) that schrundlines are best devel-

5 Mies

Vi^iv

^-^^Wiiv

GLACIAL FEATURES 305

oped in the mature stages of topographic development in the gla-
cial cycle; (5) that the varying rates of snow, neve, and ice motion
at a valley head are the persistent features to which we must look
for topographic variations; (6) that the hypothesis here pro-
posed is applicable to all cases whether they involve the presence
of snow or neve or ice or any combination of these, and whether
bergschrunds are present or not; and (7) at the same time affords
a reasonable explanation for such variations in forms as the com-
pound cirque with its schrundline and terrace, the unbroken cirque
wall, the notched cirque, and the recessed, snow-covered mountain
slopes unaffected by ice.

ASYMMETRICAL, CREST LINES AND ABNORMAL VALLEY PROFILES IN THE

CENTRAL ANDES

To prove that under similar conditions glacial erosion may be
greater than subaerial denudation quantitative terms must be
sought. Only these will carry conviction to the minds of many
opponents of the theory that ice is a vigorous agent of erosion.
Gilbert first showed in the Sierra Nevada that headwater glaciers
eroded more rapidly than nonglacial agents under comparable
topographic and structural conditions." Oddly enough none of
the supporters of opposing theories have replied to his argu-
ments; instead they have sought evidence from other regions to
show that ice cannot erode rock to an important degree. In this
chapter evidence from the Central Andes, obtained in 1907 and
1911, will be given to show the correctness of Gilbert's proposition.

The data will be more easily understood if Gilbert's argument
is first outlined. On the lower slopes of the glaciated Sierra
Nevada asymmetry of form resulted from the presence of ice on
one side of each ridge and its absence on the other (Fig. 200).
The glaciers of these lower ridges were the feeblest in the entire
region and were formed on slopes of small extent ; they were also
short-lived, since they could have existed only when glacial con-
ditions had reached a maximum. Let the broken line in the upper

" Op. cit., p. 300; see pp. 579-588 and Fig. 8.

306 THE ANDES OF SOUTHERN PERU

part of the figure represent the preglacial surface and the solid
line beneath it the present surface. It will not matter what value
we give the space between the two lines on the left to express non-
glacial erosion, since had there been no glaciers it would be the
same on both sides of the ridge. The feeble glacier occupying the
right-hand slope was able in a very brief period to erode a de-
pression far deeper than the normal agents of denudation were
able to erode in a much longer period, i.e., during all of intergla-
cial and postglacial time. Gilbert concludes: "The visible ice-
made hollows, therefore, represent the local excess of glacial over
nongiacial conditions."

In the Central Andes are many volcanic peaks and ridges
formed since the last glacial epoch and upon them a remarkable

SorSW NorNE S

Fig. 200 — Diagrammatic cross-section Fig. 201 — Postglacial volcano recessed

of a ridge glaciated on one side only; on shady southern side by the process ot
with hypothetical profile (broken line) nivation. Absolute elevation 18,000 feet
of preglacial surface. (5,490 m.), latitude 14° S., Maritime

Cordillera, Peru.

as}^nmetry has been developed. Looking southward one may see
a smoothly curved, snow-free, northward-facing slope rising to a
crest line which appears as regular as the slope leading to it.
Looking northward one may sec by contrast (Fig. 194) sharp
ridges, whose lower crests are serrate, separated by deeply re-
cessed, snow-filled mountain hollows. Below this highly dissected
zone the slopes are smooth. The smooth slope represents the
work of water ; the irregular slopes are the work of snow and ice.
The relation of the north and south slopes is diagrammatically
shoAvn in Fig. 201.

To demonstrate the erosive effects of snow and ice it must be
shown: (1) that the inlllnl slopes of the volcanoes are of post-
glacial age; (2) that the asymmetry is not structural; (3) that the
snow-free slopes have not had special protection, as through a
more abundant plant cover, more favorable soil texture, or other-
wise.

GLACIAL FEATURES 307

Proof of the postglacial origin of the volcanoes studied in this
connection is afforded: (1) by the relation of the flows and the
ash and cinder beds about the bases of the cones to the glacial
topography; (2) by the complete absence of glacial phenomena be-
low the present snowline. Ascending a marginal valley (Fig. 202),
one comes to its head, where two tributaries, with hanging rela-
tions to the main valley, come down from a maze of lesser valleys
and irregular slopes. Glacial features of a familiar sort are every-
where in evidence until we come to the valley heads. Cirques, re-
versed grades, lakes, and striae are on every hand. But at alti-
tudes above 17,200 feet, recent volcanic deposits have over large
areas entirely obscured the older glacial topography. The glacier
which occupied the valley of Fig. 202 was more than one-quarter
of a mile wide, the visible portion of its valley is now over six
miles long, but the extreme head of its left-hand tributary is so
concealed by volcanic material that the original length of the gla-
cier cannot be determined. It was at least ten miles long. From
this point southward to the border of the Maritime Cordillera no
evidence of past glaciation was observed, save at Solimana and
Coropuna, where slight changes in the positions of the glaciers
have resulted in the development of terminal moraines a little be-
low the present limits of the ice.

From the wide distribution of glacial features along the north-
eastern border of the Maritime Cordillera and the general absence
of such features in the higher country farther south, it is con-
cluded that the last stages of volcanic activity were completed in
postglacial time. It is equally certain, however, that the earlier
and greater part of the volcanic material was ejected before
glaciation set in, as shown by the great depth of the canyons (over
5,000 feet) cut into the lava flows, as contrasted with the rela-
tively slight filling of coarse material which was accumulated on
their floors in the glacial period and is now in process of dissec-
tion. Physiographic studies throughout the Central Andes demon-
strate both the general distribution of this fill and its glacial
origin.

So recent are some of the smaller peaks set upon the lava

308 THE ANDES OF SOUTHERN PERU

plateau that forms the greater part of the Maritune Cordillera,
that the snows massed on their shadier slopes have not yet ef-
fected any important topographic changes. The symmetrical
peaks of this class are in a few cases so very recent that they are
entirely uneroded. Lava flows and beds of tuff appear to have
originated but yesterday, and shallow lava-dammed lakes retain
their original shore relations. In a few places an older topog-
raphy, glacially modified, may still be seen showing through a
veneer of recent ash and cinder deposits, clear evidence that the
loftier parts of the lava plateau were glaciated before the last
volcanic eruption.

The asymmetry of the peaks and ridges in the Maritime Cordil-
lera cannot be ascribed to the manner of eruption, since the con-
trast in declivity and form is persistently between northern and
southern slopes. Strong and persistent winds from a given direc-
tion undoubtedly influence the form of volcanoes to at least a
perceptible degree. In the case in hand the ejectamenta are
ashes, cinders, and the like, which are blown into the air and have
at least a small component of motion down the wind during both
their ascent and descent. The prevailing winds of the high
plateaus are, however, easterly and the strongest winds are from
the west and blow daily, generally in the late afternoon. Both
wind directions are at right angles to the line of asymmetry, and
we must, therefore, rule out the winds as a factor in effecting the
slope contrasts which these mountains display.

It remains to be seen what influence a covering of vegetation
on the northern slopes might have in protecting them from ero-
sion. The northern slopes in this latitude (14° S.) receive a
nnicli greater quantity of heat than the southern slopes. Above
18,000 feet (5,490 m.) snow occurs on ilio shady southern slopes,
hilt is at least a thousand feet higher on the northern slopes. It
is tliercfore al)S('nt from the uorlhorn side of all but the highest
peaks. Thus vegetation on the northern slopes is not limited by
snow. Bunch grass— the characteristic ichu of the mountain
shepherds— scattered spears of smaller grasses, large ground
mosses called yareta, and lichcus cxteud to the snowline. This

GLACIAL FEATURES 309

vegetation, however, is so scattered and thin above 17,500 feet
(5,330 m.) that it exercises no retarding influence on the run-off.
Far more important is the porous nature of the volcanic material,
which allows the rainfall to be absorbed rapidly and to appear in
springs on the lower slopes, where sheets of lava direct it to the
surface.

The asymmetry of the north and south slopes is not, then, the
result of preglacial erosion, of structural conditions, or of special
protection of the northern slopes from erosion. It must be con-
cluded, therefore, that it is due to the only remaining factor —
snow distribution. The southern slopes are snow-clad, the north-
ern are snow-free — in harmony with the line of asymmetry. The
distribution of the snow is due to the contrasts between shade and
sun temperatures, which find their best expression in high alti-
tudes and on single peaks of small extent. Frankland's observa-
tions with a black-bulb thermometer in vacuo show an increase in
shade and sun temperatures contrasts of over 40° between sea
level and an elevation of 10,000 feet. Violle's experiments show
an increase of 26 per cent in the intensity of solar radiation be-
tween 200 feet and 16,000 feet elevation. Many other observa-
tions up to 16,000 feet show a rapid increase in the difference be-
tween sun and shade temperatures with increasing elevation. In
the region herein described where the snowline is between 18,000
and 19,000 feet (5,490 to 5,790 m.) these contrasts are still further
heightened, especially since the semi-arid climate and the conse-
quent long duration of sunshine and low relative humidity afford
the fullest play to the contrasting forces. The coefficient of ab-
sorption of radiant energy by water vapor is 1,900 times that of
air, hence the lower the humidity the more the radiant energy
expended upon the exposed surface and the greater the sun and
shade contrasts. The effect of these temperature contrasts is
seen in a canting of the snowline on individual volcanoes amount-
ing to 1,500 feet in extreme instances. The average may be placed
at 1,000 feet.

The minimum conditions of snow motion and the bearing of
the conclusions upon the formation of cirques have been described

310 THE ANDES OF SOUTHERN PERU

in the chapters immediately preceding. It is concluded that snow
moves upon 20° slopes if the snow is at least forty feet deep,
and that through its motion under more favorable conditions of
greater depth and gradient and the indirect effects of border
melting there is developed a hollow occupied by the snow. Actual
ice is not considered to be a necessary condition of either move-
ment or erosion. We may at once accept the conclusion that the
invariable association of the cirques and steepened profiles with
snowfields proves that snow is the predominant modifying agent.

An argument for glacial erosion based on profiles and steep
cirque walls in a volcanic region has peculiar appropriateness in
view of the well-known sjTnmetrical form of the typical volcano.
Instead of varied forms in a region of complex structure long
eroded before the appearance of the ice, we have here simple
forms which immediately" after their development were occupied
by snow. Ever since their completion these cones have been
eroded by snoiv on one side and by ivater on the other. If snow
cannot move and if it protects the surface it covers, then this sur-
face should be uneroded. All such surfaces should stand higher
than the slopes on the opposite aspect eroded by water. But these
assumptions are contrary to fact. The slopes underneath the
snow are deeply recessed; so deeply eroded indeed, that they are
bordered by steep cliffs or cirque walls. The products of erosion
also are to some extent displayed about the border of the snow
cover. In strong contrast the snow-free slopes are so slightly
modified that little of their original symmetry is lost — only a few
low hills and shallow valleys have been formed.

The measure of the excess of snow erosion over water erosion
is therefore the difference between a northern or water-formed
and a southern or snow-formed profile, Fig. 200. This difference
is also shown in Fig. 201 and from it and the restored initial pro-
files wc conclude that the rate of water erosion is to that of niva-
tion as 1 : 3. This ratio has been derived from numerous obser-
vations on cones so recently formed that the interiluves without
question are still intact.

Thus far onlv those volcanoes have been considered which

GLACIAL FEATURES

311

have been modified by nivation. There are, however, many vol-
canoes which have been eroded by ice as well as by snow and
water. It will be seen at once that where a great area of snow is
tributary to a single valley, the snow becomes compacted into
neve and ice, and that it then erodes at a much faster rate. Also
a new force — plucking — is

called into action when ice is
present, and this greatly ac-
celerates the rate of erosion.
While it lies outside the

limits of my subject to de- ^iq. 202— Graphic representation of

termine quantitatively the'"" amount of glacial erosion during the glacial

period. In the background are mature slopes
surmounted by recessed asymmetrical peaks.
The river entrenched itself below the mature
slopes before it began to aggrade, and, when ag-
gradation set in, had cut its valley floor to
a'-b'-c. By aggradation the valley floor was
raised to a-b while ice occupied the valley head.
By degradation the river has again barely
lowered its channel to a'-b', the ice has disap-
peared, and the depression of the profile repre-
sents the amount of glacial erosion,
a'-b'-c z= pregUicial profile,
a-b-d-c z= present profile,
b'-d-c-b = total ice erosion in the glacial

period,
a-b =; surface of an alluvial valley fill
due to excessive erosion at valley
head,
b-b' = terminal moraine,
d-c = cirque wall,
e, e' e" = asymmetrical summits.

ratio between water and ice
action, it is worth pointing
out that by this method a
ratio much in excess of 1 : 3
is determined, which even in
this rough form is of con-
siderable interest in view of
the arguments based on the
protecting influence of both
ice and snow. I have, in-
deed, avoided the question
of ice erosion up to this
point and limited myself to
those volcanoes which have
been modified by nivation only, since the result is more striking
in view of the all but general absence of data relating to this form
of erosion.

If we now turn to the valley profiles of the glaciated portions
of the Peruvian Andes, we shall see the excess of ice over water
erosion expressed in a manner equally convincing. To a thought-
ful person it is one of the most remarkable features of any gla-
ciated region that the flattest profiles, the marshiest valley flats,
and the most strongly meandering stretches of the streams should
occur near the heads of the valleys. The mountain shepherds

312

THE ANDES OF SOUTHERN PERU

8.2

<1>

;>>

'-3

■""

CJ
03

"to -3

-4->

-4J

.4^
1

OQ
09

;5)

'0
rt

'■^

o
p

"So

3
c«

"cj

■ —

o
o

c
.2

03
CJ

01
CJ

CJ
CJ

*ai

k«

1*3

f-)

-»->

■*j

P*i

• n

_o^

'"^

£>„

o
"m

"cj

■1^

3'
.2

^
^

-n

t^i

-(J
aj

CD
O

rr.

_CJ

CJ
03

3
ci
CJ

'E.

PL,

■tj

I-.

't-

CJ
03

■*^

3
O

OJ
01
03

cS
CJ

-4^

-a

1-3

• ».

<*H

i->

-*J

rZn

cJ
13

-l->

***

CL,

U-,

fc;

-t->

-4J

3
OS

01
01

■f:>

'•5

'/J

.2,

-•->

■♦-»

«3

tccq

t-i

-t->

C3
ll

fe<

•4^

-1

recognize this condition and
drive their flocks up from
the warmer valley into the
mountain recesses, confi-
dent that both distance
and elevation will be off-
set by the extensive pas-
tures of the finest icliu
grass. Indeed, to be near
the grazing grounds of
sheep and llamas which are
their principal means of
subsistence, the Indians
have built their huts at the
extraordinarily lofty eleva-
tions of 16,000 to 17,000 feet.

An examination of a
large number of these val-
leys and the plotting of
their gradients discloses
the striking fact that the
heads of the valleys were
deeply sunk into the moun-
tains. It is thus possible
by restoring the preglacial
profiles to measure with
considerable certainty the
excess of ice over water
erosion.

The results are graphi-
cally expressed in I'ig. 202.
It will be seen that until
glacial conditions inter-
vened the stream was flow-
ing on a rock floor. During
the whole of glacial time it

GLACIAL FEATURES 313

was aggrading its rock floor below h' and forming a deep valley
fill. A return to warmer and drier conditions led to the dis-
section of the fill and this is now in progress. The stream has
not yet reached its preglacial profile, but it has almost reached it.
We may, therefore, say that the preglacial valley profile below b'
fixes the position of the present profile just as surely as if the
stream had been magically halted in its work at the beginning of the
period of glaciation. There, b'-d-c-h represents the amount of ice
erosion. To be sure the line b-c is inference, but it is reasonable in-
ference and, whatever position is assigned to it, it cannot be coin-
cident with b'-d, nor can it be any^vhere near it. The break in the
valley profile at b' is always marked by a terminal moraine, re-
gardless of the character of the rock. This is not an accidental
but a causal association. It proves the power of the ice to erode.
In glacial times it eroded the quantity b-c-d-b'. This is not an
excess of ice over water erosion, but an absolute measure of ice
erosion, since a'-b' has remained intact. The only possible error
arises from the position assigned b-c, and even if we lower it to
b-c (for which we have no warrant but extreme conservatism) we
shall still have left b'-c'-d-b as a striking value for rock erosion
(plucking and abrasion) by a valley glacier.

A larger diagram, Fig. 203, represents in fuller detail the
topographic history of the Andes of southern Peru and the rela-
tive importance of glaciation. The broad spurs mth grass-
covered tops that end in steep scarps are in wonderful contrast to
the serrate profiles and truncated spurs that lie within the zone
of past glaciation. In the one case we have minute irregularities
on a canyon wall of great dimensions; in the other, more even
walls that define a glacial trough with a flat floor. Before glacia-
tion on a larger scale had set in the right-hand section of the dia-
gram had a greater relief. It was a residual portion of the moun-
tain and therefore had greater height also. Glaciers formed upon
it in the Ice Age and glaciation intensified the contrast between
it and the left-hand section ; not so much by intensifying the relief
as by diversifying the topographic forms.

,-!»-*'^.

kances

»«»A, ..|_r "C JH'UDQirtBCA

StBnrButatnjOe-

APPENDIX A

SURVEY METHODS EMPLOYED IN THE CONSTRUCTION OF
THE SEVEN ACCOMPANYING TOPOGRAPHIC SHEETS

By Kai Hendriksen, Topographer

The main part of the topographical outfit consisted of (1) a 4-inch
theodolite, Buff and Buff, the upper part detachable, (2) an 18 x 24 inch
plane-table with Johnson tripod and micro-meteralidade. These instru-
ments were courteously loaned the expedition by the U. S. Coast and
Geodetic Survey and the U. S. Geological Survey respectively.

The method of survey planned was a combination of graphic triangula-
tion and traverse with the micro-meteralidade. All directions were plotted
on the plane-table which, was oriented by backsight ; distances were deter-
mined by the micro-meteralidade or triangulation, or both combined; and
elevations were obtained by vertical angles. Finally, astronomical observa-
tions, usually to the sun, were taken at intervals of about 60 miles for
latitude and azimuth to check the triangulation. No observations were
made for differences in longitude because this would probably not have
given any reliable result, considering the time and instruments at our
disposal. Because the survey was to follow very closely the seventy-third
meridian west of Greenwich, directions and distances, checked by latitude
and azimuth observations, undoubtedly afforded far better means of deter-
mining the longitude than time observations. In other words, the time
observations made in connection with azimuth observations were not used
for computing longitudinal differences. Absolute longitude was taken
from existing observations of principal places.

Principal topographical points were located by from two to four inter-
sections from the triangulation and plane-table stations; and elevations
were determined by vertical angle measurements. Whenever practicable,
the contours were sketched in the field; the details of the topography
otherwise depend upon a great number of photographs taken by Pro-
fessor Bowman from critical stations or other points which it was possible
to locate on the maps.

Cross-Section Map from Abancay to CamanX at the Pacific Ocean

Seven sheets. Scale, 1 : 125,000 ; contour interval, 200 feet. Datum is mean
sea level. Astronomical control : 5 latitude and 5 azimuth observations as
indicated on the accompanying topographic sheets.

315

316 APPENDIX A

On September 10th, returning from a reconnaissance survey of the
Pampaconas Eiver, I joined Professor Bowman's party, Dr. Erving acting
as my assistant. We crossed the Cordillera Vilcapampa and the Canyon
of the Apurimac and after a week's rest at Abancay started the
topographic work near Hacienda San Gabriel south of Abancay. Working
up the deep valley of Lambrama, observations for latitude and azimuth
were made midwaj^ between Hacienda Matara and Caypi.

On October -Ith we made our camp in newly fallen snow surrounded by
beautiful glacial scenery. The next day on the high plateau, we passed
sharp-crested glaciated peaks; a heavy thunder and hail storm broke out
while I occupied the station at the pass, the storm continuing all the after-
noon — a frequent occurrence. The camp was made 6 miles farther on, and
the next morning I returned to finish the latter station. I succeeded in
sketching the detailed topography just south of the pass, but shortly after
noon, a furious storm arose similar to the one the day before, and made
further topographic work impossible; to get connection farther on I
patiently kept my eye to the eye-piece for more than an hour after the
storm had started, and was fortunate to catch the station ahead in a single
glimpse. I had a similar experience some days later at station 16,079,
Antabamba Quadrangle, on the rim of the high-level puna, the storm pre-
venting all topographic work and barely allowing a single moment in which
to catch a dim sight of the signals ahead while I kept my eye steadily at
the telescope to be ready for a favorable break in the heavy clouds and hail.
At Antabamba we got a new set of Indian carriers, who had orders to
accompany us to Cotahuasi, the next sub-prefectura. Raimondi's map
indicates the distance between the two cities to be 35 miles, but although
nothing definite was stated, we found out in Antabamba that the distance
was considerably longer, and moreover that the entire route lay at a high
altitude.

From the second day out of Antabamba until Huaynacotas was in sight
in the Cotahuasi Canyon, a distance of 50 miles, the route lay at an
altitude of from 16,000 to 17,630 feet, taking in 5 successive camps at an
altitude from 15,500 to 17,000 feet; 12 successive stations had the following
altitudes:

16,379 feet

1G,852 "

17,104 "

17,r)5n "

1 7,07.1 " - Iiif^^licst stalion occupied.

17,008 "

17,633 "

10,305 "

17,630 "

17,128 "

16,794 "

16,200 "

APPENDIX A 317

The occupation of these high stations necessitated a great deal of
climbing, doubly hard in this rarefied air, and often on volcanoes with a
surface consisting of bowlders and ash and in the face of violent hailstorms
that made extremely difficult the task of connecting up observations at
successive stations.

At Cotahuasi a new pack-train was organized, and on October 25th I
ventured to return alone to the high altitudes in order to continue the
topography at the station at 17,633 feet on the summit of the Maritime
Cordillera. Dr. Erving was obliged to leave on October 18th and Professor
Bowman left a week later in order to carry out his plans for a physi-
ographic study of the coast between Camana and Mollendo. Philippi
Angulo, a native of Taurisma, a town above Cotahuasi, acted as major-
domo on this journey. Knowing the trail and the camp sites, I was able
to pick out the stations ahead myself, and made good progress, returning
to Cotahuasi on October 29th, three or four days earlier than planned.
From Cotahuasi to the coast I had the assistance of Mr. AVatkins. The most
trying part of the last section of high altitude country was the great
Pampa Colorada, crowned by the snow-capped peaks of Solimana and
Coropuna, reaching heights of 20,730 and 21,703 feet respectively. The
passing of this pampa took seven days and we arrived at Chuquibamba on
November 9th. Two circumstances made the work on this stretch
peculiarly difficult — the scarcity of camping places and the high tempera-
ture in the middle of the day, which heated the rarefied air to a degree
that made long-distance shots very strenuous work for the eyes. Although
our base signals were stone piles higher than a man, I was often forced to
keep my eye to the telescope for hours to catch a glimpse of the signals;
lack of time did not allow me to stop the telescope work in the hottest part
of the day.

The top of Coropuna was intersected from the four stations:
16,344, 15,545, 16,168, and 16,664 feet elevation, the intersections giving
a very small triangular error. The elevation of Mount Coropuna 's high
peak as computed from these 4 stations is :

21,696 feet
21,746 "
21,714 "
21,657 "

Mean elevation 21,703 feet above sea level.

The elevation of Coropuna as derived from these four stations has thus
a mean error of 18 feet (method of least squares) while the elevation of
each of the four stations as carried up from mean sea level through 25
stations — vertical angles being observed in both directions — has an esti-

318 APPENDIX A

mated mean error of 30 feet. The result of this is a mean error of 35 feet
in Coropuna's elevation above mean sea level.

The latitude is 15^ 31' 00" S. ; the longitude is 72° 42' 40" ^Y. of Green-
wich, the checking of these two determinations giving a result unexpectedly
close.

On November 11th azimuth and latitude observations were taken at
Chuquibamba and two days later we arrived at Aplao in the bottom of the
splendid Majes Valley. In the northern part of this valley I was prevented
from doing any plane-table work in the afternoons of four successive days.
A strong gale set in each noon raising a regular sandstorm, that made
seeing almost impossible, and blowing with such a velocity that it was
impossible to set up the plane-table.

From Hacienda Cantas to Camana we had to pass the western desert
for a distance of 45 miles. We were told that on the entire distance there
was only one camping place. This was at Jaguey de Majes, where there
was a brook with just enough water for the animals but no fodder. Thus
Ave faced the necessity of carrying water for ten men and fodder for 14
animals in excess of the usual cargo; and we were unable to foretell how
many days the topography over the hot desert would require.

Although plane-table work in the desert was impossible at all except in
the earliest and latest hours of the day, we made regular progress. We
camped three nights at Jaguey and arrived on the fourth day at Las
Lomas.

The next morning, on November 23rd, at an elevation of 2178 feet near
the crest of the Coast Range, we were repaid for two months of laborious
work by a glorious view of the Pacific Ocean and of the city of Camana with
her olive gardens in the midst of the desert sand.

The next day I observed latitude and azimuth at Camana and in the
night my companion and assistant Mr. Watkins and I returned across the
desert to the railroad at Yitor.

Conclusions

The planned methods were followed very closely. In two cases only
the plane-table had to be oriented by the magnetic needle, the backsights
not being obtainable because of the impossibility of locating the last sta-
tion, passing Indians having removed the signals.

In one case only the distance between two stations had to be deter-
mined by graphic triangulation exclusively, the base signals having been
destroyed. Otherwise graphic triangulation was used as a check on
distances.

X'ertical angles were always measured in both directions with the
oxcrption of the a])ove-montionod cases.

Observations for aziniulli wwo alwavs lal^cii to the sun boforo and

APPENDIX A 319

after noon. The direction used in the azimuth observation was also taken
with the prismatic compass. The mean of the magnetic declination thus
found is : East 8° 30' plus.

Observations for latitude were taken to the sun by the method of
circum-meridian altitudes, except at the town of Vilcabamba where star
observations were taken.

As a matter of course, observations to the sun are not so exact as star
observations, especially in low latitudes where one can expect to observe
the near zenith. However, working in high altitudes for long periods,
moving camp every day and often arriving at camp 2 to 4 hours after
sunset, I found it essential to have undisturbed rest at night. It was
beyond my capacity to spend an hour or two of the night in finding the
meridian and in making the observation. Furthermore, the astronomic
observations were to check the topography mainly, the latter being the
most exact method with the outfit at hand.

The following table contains the comparisons between the latitude sta-
tions as located on the map and by observation :

Map Observation

Camana Quadrangle S 16° 37' 34" 16° 37' 34" '

Coropuna, station 9,691S 15° 48' 30" (15° 51' 44")

Cotahuasi, " 12,588S 15° 11' 40" 15° 12' 30"

La Cumbre, " 16,852S 14° 28' 10" 14° 29' 46"

Lambrama, " 8,341S 13° 43' 18" 13° 43' 14"

The other observations, with the exception of the one on the Coropuna
Quadrangle, check probably as well as can be expected with the small and
light outfit which we used, and under the exceptionally hard conditions of
work. The observation on the Coropuna Quadrangle just south of
Chuquibamba is, however, too much out. An explanation for this is that
the meridian zenith distance was 1° 23' 12" only (in this case the exact
formula w^as used in computing) . Of course, an error or an accumulation
of errors might have been made in the distances taken by the micrometer-
alidade, but the first cause of error mentioned is the more probable, and
this is indicated also by the fact that the location on the top of Mount
Coropuna checks closely with the one determined in an entirely independent
way by the railroad engineers.

For the cross-section map from Abancay to Camana, the following
statistics are desirable :

* The observation at Camana checks very closely with a Peruvian observation the

value of which is S. 16° 37' 00".

320 APPENDIX A

Micrometer traverse and graphic triang-ulation, with contours, field scale
1 : 90,000.

Total time required, days 40.5

Average distance per days in miles 7.5

Average number of plane-table stations occupied per day 1.5

Average area per day in square miles 38.

Located points per square mile 0.25

Approximate elevations in excess of above, per square mile 0.25

Highest station occupied, feet above sea level 17,675.

Highest point located, feet above sea level 21,703.

APPENDIX B

Fossil Determinations

A FEW fossil collections were gathered in order that age determinations
might be made. With the following identifications I have included a few
fossils (I and II) collected by W. R. Rumbold and put into my hands in
1907. The Silurian is from a Bolivian locality south of La Paz but in the
great belt of shales, slates, and scliists which forms one of the oldest sedi-
mentary series in the Eastern Andes of Peru as well as Bolivia. While
no fossils were found in this series in Peru the rocks are provisionally
referred to the Silurian. Fossil-bearing Carboniferous overlies them but
no other indication of their age was obtained save their general position in
the belt of schists already mentioned. I am indebted to Professor Charles
Schuchert of Yale University for the following determinations.

I. Silurian

San Roque Mine, southwest slope of Santa Vela Cruz, Canton Ichoeu, Prov-
ince Inquisivi, Bolivia.

Sent by William R. Rumbold in 1907.

Climacograptus ?

Pholidops trombetana Clarke?

Chonetes striatellus (Dalman).

Atrypa marginalis (Dalman) ?

Ccelospira n. sp.

Ctenodonta, 2 or more species.

Hyolithes.

Klosdenia.

Calymene ?

Dalmanites, a large species with a terminal tail spine.

Acidaspis.
These fossils indicate unmistakably Silurian and probably Middle Silurian.
As all are from blue-black shales, brachiopods are the rarer fossils, while bivalves
and trilobites are the common forms. The faunal aspect does not suggest relation-
ship with that of Brazil as described by J. M. Clarke and not at all with that of
North America. I believe this is the first time that Silurian fossils have been
discovered in the high Andes.

II. Lower Devonian

Near north end of Lake Titicaca.

Leptocoelia flahelUtes (Conrad), very common.
Atrypa reticularis (Linnseus) ?

321

322 APPENDIX B

This is a part of the well-known and widely distributed Lower Devonian fauna
of the southern heraisphere.

III. Upper Carboniferous

All of the Upper Carboniferous lots of fossils represent the well-known
South American fauna first noted by d'Orbigny in 1842, and later added to by
Orville Derby. The time represented is the equivalent of the Pennsylvanian of
North America.

Huascatay between Pasaje and Huancarama.
Crinoidal limestone.
Trepostomata Brj'Ozoa.
Pohjpora. Common.

Streptorhynchus hallianus Derby. Common.
Chonetes glaher Geinitz. Rare.
Productus humholdii d'Orb. Rare,
" cora d'Orb. Rare.

" chandlessii Derby.

" sp. undet. Common.

" sp. undet. "

Spirifer condor d'Orb. Common.
Hustedia mormoni (Marcou). Rare.
Seminula argentea (Shepard). "
Pampaconas, Pampaconas valley near Vilcabamba.
Lophophyllum?
Rhombopora, etc.
Productus.

Camarophoria. Common.
Spirifer condor d'Orb.
Hustedia mormoni (Marcou).
Euomphalus. Large form.
Pongo de I^fainique. Extreme eastern edge of Peruvian Cordillera.
Lophophyllum.
Productus chandlessii Derby.

" cora d'Orb.

Orthotetes correanus (Derby).
Spirifer condor d'Orb.
River bowlders and stones of Urubamba river, just beyond eastern edge of
Cordillera at mouth of Ticumpinea river. (Detached and transported by stream
action from the Upper Carbon iforons at Pongo de Mainique.)
Mostly Trepostomata Bryozoa.
Many Productus spines.
Productus cora d'Orb.
Cfniiarophnria. Sanif as at I'ainpaconos.
I'rndiirtus sp. uiidcl.
Cotahviasi A.

Lophophyllum.
Productus peruvianus d'Orb.
" sp. undet.

APPENDIX B 323

Camarophoria.
Pugnax near utah (Marcou).
Seminula argentea (Shepard) ?
Cotahuasi B.

Productus cora d'Orb.

" near semireticulatus (Martin).

IV. Comanchian or Lower Cretaceous

Near Chuquibambilla.

Pecten near quadricostatus Sowerby.

Undet. bivalves and gastropods.

The eehinid Laganumf colomhianum d'Orb. A clypeasterid.
This Lower Cretaceous locality is evidently of the same horizon as that of
Colombia illustrated by d'Orbigny in 1842 and described on pages G3-105.

APPENDIX C

KEY TO PLACE NAMES

Abancay, towii, lat. 12° 35', Figs. 20, 204.
Abra Tocate, pass, between Yavero and

Urubamba valleys, leaving latter at

Rosalina, (Fig. 8). See also Fig. 55.
Anta, town, lat. 13° 30', Fig. 20.
AntabaJiiba, town, lat. 14° 20', Figs. 20,

204.
Aplao, town, lat. 16°, Figs. 20, 204.
Apurimae, river, Fig. 20.
Arequipa, to\\Ti, lat. 16° 30', Fig. 66.
Arica, town, northern Chile, lat. 18° 30'.
Arma, river, tributary of Apurimae, lat.

13° 25', (Fig. 20) ; tributary of Ocoiia,

lat. 15° 30', (Fig. 20).
Arma, village, lat. 13° 15', Fig. 20. See

also Fig. 140.
Auquibamba, hacienda, lat. 13° 40', Fig.

204.

Callao, town, lat. 12°, Fig. 66.

Camana, town, lat. 10° 40', Figs. 20, 66,
204.

Camisea, river, tributary of Urubamba en-
tering from right, lat. 11° 15'.

Camp 13, lat. 14° 30'.

Cantas, hacienda, lat. 16° 15', Fig. 204.

Caraveli, town, lat. 16°, Fig. GO.

Catacaos, town, lat. 5° 30', Fig. 66.

Caylloma, town and mines, lat. 15° 30',
Fig. 66.

Caypi, village, lat. 13° 45'.

Central Ranges, lat. 14°, Fig. 20. See also
Fig. 157.

f'crro Azul, town, lat. 13°, Fig. GO.

(huchani, nit., overlooking Arequipa, lat.
IC' 30', (Fig. 06).

Chaupiniayii, river, tributary of Uru-
bamba entering at Sahuayaco, q.v.

C'liiii, river, tributary of X'ilor River, lat.
10° 30', (Fig. 06).

Cliinclie, liacienda, Urubamba Valley
above Santa Ana, lat. 13', (Fig. 20).

Chira, river, lat. 5°, Fig. 66.

Choclococlia, lake, lat. 13° 30', Fig'^. 66, 68.

Clioqquequirau, ruitiH, canyon of Apurimae

above junction of Pachachaca River, lat.

13° 25', (Fig. 20).
Choquetira, village, lat. 13° 20', Fig. 20.

See also Fig. 136.
Chosica, village, lat. 12°, Fig. 66.
Chuquibamba, town, lat. 15° 50', Figs. 20,

204.
Chuquibambilla, village, lat. 14°, Figs. 20,

204.
Chuquito, pass, Cordillera Vilcapampa be-
tween Arma and Vilcabamba valleys,

lat. 13° 10', (Fig. 20). See also Fig.

139.
Coast Range, Figs. 66, 204.
Coehabamba, city, Bolivia, lat. 17° 20',

long. 66° 20'.
Colorada, pampa, lat. 15° 30', Fig. 204.
Colpani, village, lower end of Canyon of

Torontoy (Urubamba River), lat. 13°

10'. See Fig. 158.
Copacavana, village, Bolivia, lat, 16° 10',

long. G9° 10'.
Coribeni, river, lat. 12° 40', Fig. 8.
Coropuna, mt., lat. 15° 30', Figs. 20, 204.
Corralpata, village, Apurimae Valley near

Incahuasi.
Cosos, village, lat. 16°, Fig. 204.
Cotabambas, town, Apurimae Valley, lat.

13° 45', (Fig. 20).
Cotahuasi, town, lat. 15° 10', Figs. 20,

204.
Cn/co, city, lat. 13° 30', Fig. 20.

Keharali, hacienda, on the Urubamba
River between Santa Ana and Rosalina,
lat. 12° 40'. Sec inset map. Fig. 8,
and also Fig. 54.

Iliiadquifia, hacienda, Urubamba River

above junction with Vilcabamba, lat.

13" 10', (Fig. 20). See also Fig. 158.
liuachiuirea, villag<-, lat. 14° 15', Figs. 20,

201.
lliuiipo, lake, north of Anta, lat. 13° 25',

(Fig. 20).

324

APPENDIX C

325

Huambo, village, left bank Paeliacliaca
River between Huancarama and Pasaje,
lat. 13° 35', (Fig. 20).

Huancarama, town, lat. 13° 40', Fig. 20.

Huancarqui, village, lat. 10° 5', Fig. 204.

Huascatay, village, left bank of Apuriniac
above Pasaje, lat. 13° 30', (Fig. 20).

Huaynacotas, village, lat. 15° 10', Fig. 204.

Huichihua, village, lat. 14° 10', Fig. 204.

(Tablazode) lea, plateau, lat. 14°-15° 30',

Fig. 66.
lea, town, lat. 14°, Figs. 66, 67.
Incahuasi, village, lat, 13° 20', Fig. 20.
Iquique, town, northern Chile, lat. 20° 15'.
(Pampa de) Islay, south of Vitor River,

(Fig. 66).

Jaguey, village, Pampa de Sihuas, q.v.

La Joya, pampa, station on Mollendo-

Puno R.R., 16° 40', (Fig. 66).
Lambrama, village, lat. 12° 50', Fig. 20.
Lima, city, lat. 12°, Fig. 66.

Machu Picchu, ruins, gorge of Torontoy,

q.v., lat. 13° 10'.
Majes, river. Fig. 204.
Manugali, river, tributary of Urubamba

entering from left above Puviriari

River, lat. 12° 20', (Fig. 8).
Maritime Cordillera, Fig. 204.
Matara, village, lat. 14° 20', Fig. 204.
(El) Misti, mt, lat. 16° 30', Fig. 66.
Mollendo, town, lat. 17°, Fig. 66.
Moquegua, town, lat. 17°, Fig. 66.
Morococlia, mines, lat. 11° 45', Fig. 66.
Mulanquiato, settlement, lat. 12° 10',

Fig. 8.

Occobamba, river, uniting with Yanatili,
q.v.

Ocona, river, lat. 15°-16° 30', Figs. 20, 66.

Ollantaytambo, village, Urubamba River
below Urubamba town, lat. 13° 15',
( Fig. 20 ) , and see inset nlap. Fig. 8.

Pabellon, hacienda, Urubamba River above
Rosalina, (Fig. 20). See also Fig. 55.

Pacasmayo, town, lat. 7° 30', Fig. 66.

Pachatusca (Pachatusun), mt., overlook-
ing Cuzco to northeast, lat. 13° 30'.

Pachitea, river, tributary of Ucayali en-
tering from left, lat. 8° 50'.

Paita, town, lat. 5°, Fig. 66.

Pampacolca, village, south of Coropuna,
q.v.

Panipaconas, river, known in lower course
as Cosireni, tributary of Urubamba
River, (Fig. 8). Source in Cordillera
Vilcapampa west of Vilcabamba.

Pampas, river, tributary of Apurimac en-
tering from left, lat. 13° 20'.

Panta, mt., Cordillera Vilcapampa, north-
west of Arma, lat. 13° 15', (Fig. 20).
/S'ce also Fig. 136.

Panticalla, pass, Urubamba Valley above
Torontoy, lat. 13° 10'.

Pasaje, hacienda and ferry, lat. 13° 30',
Fig. 20.

Paucartambo (Yavero), river, q.v.

Paucartambo, town, head of Paucartambo
(Yavero) River, lat. 13° 20', long. 71°
40'. Inset map, Fig. 8.

Pichu-Pichu, mt., overlooking Arequipa,
lat. 16°, (Fig. 00).

Pileopata, river, tributary of Upper Madre
de Dios east of Paucartambo, lat. 13°.

Pini-pifii, river, tributary of Upper Madre
de Dios east of Paucartambo, lat. 13°.

Pisco, town, lat. 14°, Fig. 06.

Piura, river, lat. 5°-6°, Fig. 66.

Piura, town, lat. 5° 30', Fig. 00.

Pomareni, river, lat. 12°, Fig. 8.

Pongo de Mainique, rapids, lat. 12°,
Fig. 8.

Pucamoco, hacienda, Urubamba River, be-
tween Santa Ana and Rosalina, (Fig.
20).

Puquiura, village, lat. 13° 5', Fig. 20.
See also Fig. 158. Distinguish Puqura
in Anta basin near Cuzco.
Puqura, village, Anta basin, east of Anta,
lat. 13° 30', (Fig. 20).

Quilca, town, lat. 10° 40', Fig. 06.
Quillagua, village, northern Chile, lat.
21° 30', long. 09° 35'.

Rosalina, settlement, lat. 12° 35', Fig. 8.
See also Fig. 20.

Sahuayaeo, hacienda, LTrubamba Valley
above Rosalina, (Fig. 20). See also
Fig. 55.

Salamanca, town, lat. 15° 30', Fig. 20.

Salaverry, town, lat. 8°, Fig. 66.

Salcantay, mt., lat. 13° 20', Fig. 20.

326

APPENDIX C

San Miguel, bridge, canyon of Torontoy

near Macliu Picchu, lat. 13° 10'.
Santa Ana, hacienda, lat. 12° 50', Fig. 20.
Santa Ana, river, name applied to the

Urubaniba in the region about hacienda

Santa Ana.
Santa Lucia, mines, lat. 16°, Fig. 66.
Santo Anato, hacienda. La Sama's hut,

12° 35', Fig. 8.
Sihuas, Pampa de, lat. 16° 30', Fig. 204.
Sillilica,' Cordillera, east of Iquique,

northern Chile.
Sintulini, rapids of Urubamba River

above junction of Pomareni, lat. 12° 10',

(Fig. 8).
Sirialo, river, lat. 12° 40', Fig. 8.
Soiroccocha, mt., Cordillera Vilcapampa

north of Arma, lat. 13° 15', (Fig. 20).
Solimana, mt., lat. 15° 20', Fig. 204.
Soray, mt., Cordillera Vilcapampa, south-
east of Mt. Salcantay, lat. 13° 20',

(Fig. 20).
Sotospampa, village, near Lambrama, lat.

13° 50', (Fig. 204).
Sullana, town, Chira River, lat. 5°, (Fig.

fiC).

Taurisma, village, lat. 15° 10', Fig. 204.

Ticumpinea, river, tributary of Uru-
bamba entering from right below Pongo
de Mainique, lat. 11° 50', (Fig. 8).

Timpia, river, tributary of Urubamba en-
tering from right, lat. 11° 45'.

Tono, river, tributary of Upper Madre de
Dios, cast of Paucartambo, lat. 13°.

Torontoy, canyon of the Urubamba be-
tween the villages of Torontoy and Col-
pani, lat. 13° 10'-13° 15'.

Torontoy, village at tlic head of the

canyon of the same name, lat. 13° 15'.

See inset map. Fig. 8.
Tumbez, town, lat. 4° 30', Fig. 66.
Tunari, Cerro de, mt., northwest of Co-

chabamba, q.v.

Urubamba, river. Fig. 20.

Urubamba, town, lat. 13° 20', Fig. 20.

Vilcabamba, river, tributarj' of Urubaniba
River entering from left above Santa
Ana, lat. 13°, Fig. 8. See also Fig. 158.

Vilcabamba, village, lat. 13° 5', Fig. 20.
Sec aho Fig. 158.

Vilcanota, Cordillera, southern Peru.

Vilcanota, river, name applied to Uru-
bamba above lat. of Cuzco, 13° 30', (Fig.
20).

Vilcapampa, Cordillera, lat. 13° 20', Fig.
20.

Vilque, town, southern Peru, lat. 15° 50',
long. 70° 30',

Vitor, pampa, lat. 16° 30', Fig. 66.

Vitor, river. Fig. 66.

Yanahuara, pass, between Urubamba and

Yanatili valleys, lat. 13° 10'.
Yanatili, river, tributary of Urubaniba en-
tering from right above Rosalina, (Fig.

20). Sec also Fig. 55.
Yavero (Paucartambo), river, tributary

of Urubamba entering from right, lat.

12° 10', Fig. 8.
Yavero, settlement, at junction of Yavero

and L'rubamba rivers, lat. 12° 10',

Fig. 8.
Ywngnyo, town, southern Pern, lat. 16°

20', long. 69° 10'.
Yuyato, river, lat. 12° 5', Fig. 8.

INDEX

Abancay, 32, 62, 64, 78, 92, 93, 181, 189,
221, 243; suppressing a revolution, 89-

91; temperature curve (diagr.), opp, p.

180
Abancay basin, 154
Abancay to CamanS cross-section map,

work, observation and statistics, 315
Abra Tocate, 73, 80, 81; topography and

vegetation from (ill.), opp. p. 19
Abra de Malaga, 276
Acosta, 205
Adams, G. I,, 255
Agriculture, 74-76, 152
Aguardiente, 74. See Brandy
Alcohol, 5, 6

Alluvial fans, 60-63, 70, 270 •
Alluvial fill, 270-273; view in Majes

Valley (ill.), opp. p. 230
Alpacas, 5, 52

Alto de los Huesos (ill.), opp. p. 7
Amazon basin, Humboldt's dream of (^n-

quest, 33-35; Indian tribes, 36
Amazonia, 20, 26
Ancachs, 171
Andahuaylas, 89
Andrews, A. C, 295
Angulo, Philippi, 317
Anta, 187, 189, 190
Anta basin, 62, 108, 197; geologj', 250;

view looking north from hill near Anta

(ill.), opp. p. 184
Antabamba, 52, 53, 95, 96, 99, 101, 189,

197, 243, 303, 316; Governor, 95-99,

100-101; Lieutenant Governor, 96-90,

101 ; sketch section, 243
Antabamba Canyon, view across (ill.),

opp. p. 106
Antabamba Quadrangle, 316, opp. p. 282

(topog. sheet)
Antabamba region, geologic sketch map

and section, 245
Antabamba Valley, 96
"Antis," 39
Aplao, 106, 115, 116, 181, 226, 231, 255,

256, 257, 273, 318; composite structure

section (diagr.), 259; temperature

curve (diagr.), 181

Aplao Quadrangle (topog. sheet), opp. p.

120
Appendix A, 315
Appendix B, 321
Appendix C, 324
Apurimac, 51, 57, 60, 94, 153, 154;

crossing at Pasaje (ills.), opp. p. 91;

regional diagram of canyoned country,

58
Apurimac Canyon, 189; cloud belt (ill.),

opp. p. 150
Arequipa, 52, 89, 92, 117, 120, 137,

284; glacial features near (sketches),

280
Argentina, 93
Arica, 130, 132, 198
Arma, 67, 189, 212-214
Arrieros, Pampa de, 280
Asymmetrical peaks (ill.), opp. p. 281
Asymmetry, 305-313; cross-section of ridge

(diagr.), 306; postglacial volcano

(diagr.), 306
Auquibamba, 93
Avalanches, 290

Bailey, S. I., 284

Bandits, 95

Basins, 60, 154; regional diagram, 61;

climatic cross-section (diagr.), 62
Batholith, Vilcapampa, 215-224
Belaunde brothers, 116
Bergschrunds, 294-305
Bingham, Hiram, ix, 104, 157
Block diagram of physiography of Andes,

186
Boatmen, Indian, 13
Bogota, Cordillera of, 205
Bolivia, 93, 176, 190, 1»5, 1^, 34f>, 241,

249, 322"; snowline, 275-277
Bolivian boundary, 68
Border valleys of the Eastern Andes, 68-

87
Borneo, 206

Bowman, Isaiah, 8, 316
Brandy, 74, 75, 76, 82-83
Bravo, Jos^, 245
Burastead, A. H., ix

327

328

INDEX

Cacao, 74, S3

Cacti, 150; arboreal (ill.), opp. p. 90

CalchaquI Valley, 250

Callao, 118; cloudiness (with diagr.), 133;
temperature (with diagr.), 126-129;
wind roses (diagrs.), 128

Camana, 21, 112, 115, 116, 117, 118, 140-
141, 147, 181, 225, 226, 227, 266, 318;
coastal Tertiary, 253, 254 ; plain of, 229 ;
temperature cur\-e (diagr.), 181

CamanS Quadrangle (topog. sheet), opp.
p. 114

Camand Valley, 257

CamanS-Vitor region, 117

Camino del Penon, 110

Camisea, 36

Camp 13, 100, ISO, 181; temperature curve
(diagr.), 180

Campas, 37

Canals for bringing water, 59, 60, 155;
projected. Maritime Cordillera (diagr.),
118

Cantas, 115, 116, 226, 253, 257, 273, 318

Canyon walls (ills.), opp. p. 218

Canyoned country, regional diagram, 58;
valley climates (diagr.), 59

Canyons, GO, 72, 73, 197, 219; Majes River
(ill.), opp. p. 230; topographic condi-
tions before formation of deep canyons
in Maritime Cordillera (ill.), opp. p.
184

Caraveli, climate data, 134-136; wind
ro.ses (diagrs.), 136

Carboniferous fossils, 323

Carboniferous strata, 241-247; hypo-
thetical distribution of land and sea
(diagr.), 246

Cashibos, 37

Catacaos, 119

Cattle tracks (ill.), opp. p. 226

Caucho, 29

Caylloma, 104, 165

Cay pi, 316

Central Ranges, asymmetrical peaks (ill.),
opp. p. 281 ; glacial features with lateral
moraines (ill.), opp. p. 269; glacial
tojjography between I.ambrama and
Antabamba (ill.), opp. p. 280; steep
cirque walls (ill), "pj). p. 2^6
C'erro Azul, 118
Cerro de Tunari, 176
Chachani, 280, 284
Chanchamnyo, 77
Charact<T. Hce Human character

Chaupimayu Valley, 77 •

Chicha, 86

Chile, 130, 132, 193, 260
Chili River, 120

Chili Valley, opp. p. 7 (ill.), 117
Chimborazo, 281
Chinche, 271, 272

Chira River, depth diagram, 119, 120
Chirumbia, 12
Choclococha, Lake, 120
Chonta Canipaa, 37
Choqquequirau, 154

Choquetira, 66, 67, 211; bowldery fill be-
low, 269; glacial features, 206-207
Choquetira Valley, moraine (ill.), opp. p.

208
Chosica, 136, 137; cloudiness (diagr.),

138
Chufio, 57
Chuntaguirus, 41
Chuquibamba, 54, 72, 107, 110, 111, 112,

115, 116, 273, 317-319; sediments, 258
Chuquibambilla, 53, 189, 220, 221, 222,

236, 243; alluvial fill (diagr.), 272;

Carboniferous, 244; fossils, 323
Chuquito pass, crossing (ill.), opp. p. 7;

glacial trough (ill.), opp. p. 205
Cirque walls, steep (ill.), opp. p. 286
Cirques, 294-305; development (diagr.),
300; development, further stages

(diagr.), 301; mode of formation

(diagr.), 297
Clarke, J. M., 321
Clearing in forest (ill.), opp. p. 25
Climate, const, 125-147; eastern border,

147-153; Inter-Andean valleys, 153-155;
see also Meteorological records
Climatic belts, 121-122; map, 123
Climatology, 121-156
Cliza, 276
Cloud-banners, 16
Cloud belt, 143, opp. p. 150 (ill.)
Cloudiness, 132; Callao (with diagr.),

133; desert station near Caraveli

(diagrs.), 137; Machu Picchu, 160;

Santa JiUcia (diagr.), 169
Clouds, Infer Andean Valley, 155; Santa

Ana (ill.), opp. p. IHO; S.iiiln Lueia,

168; types on eastern border nf Andes

(diagrs.), 148; sec also Fog
Coast Range, 111, 113, 114, 110, 118, 225-

232; climate, 122-147; direction, 267;

diagram to show progressive lowering

of saturation temperature in a desert.

INDEX

329

127; geology, 25S; view between Mol-
lendo and Arequipa in June (ill.)> opp.
p. 226; wet and dry seasons (diagrs.),
132

Coastal belt, map of irrigated and irriga-
ble land, 113

Coastal desert, 110-120; regional diagram
of physical relations, 112; see also
Deserts

Coastal planter, 6

Coastal region, topographic and climatic
provinces (diagr. ), 125

Coastal terraces, 225-232

Coca, 74, 77, 82-83

Coca seed beds (ill.), opp. p. 74

Cochabamba, 93; temperature (diagrs. of
ranges), insert opp. p. 178; weather
data, 176-178

Cochabamba Indians, 276

Colombia, 205

Colorada, Pampa de, 114, 317

Colpani, 72, 215, 216, 222, 223; from ice
to sugar cane (ill.), opp. p. 3

Comanchian fossils, 323

Comas, 155

Compafiia Gomera de Mainique, 29, 31, 32

Concession plan, 29

Conibos, 44

Contador, 84-85

Copacavana, 176

Cordilleras, 4, 6, 20, 197

Coribeni, 15

Corn, 57, 59, 62

Coropuna, 109, 110, 112, 202, 253, 317,
319; elevation, 317; glaciation, 307;
snowline, 283-285

Coropuna expedition, 104

Coropuna Quadrangle, 197, opp. p. 188
(topog. sheet), 319

Corralpata, 51, 59

Cosos, 231

Cotabambas, 78

Cotahuasi, 4, 5, 52, 54, 60, 97, 101, 103,
104, 180, 197, 199, 316, 317; alluvial
fill, 272; fossils, 322; geologic sketch
maps and cross-section, 247 ; rug weaver
(ill.), opp. p. 68; snowline above, 282-
283; temperature curve (diagr.), 180;
view (ill.), opp. p. 57

Cotahuasi Canyon, 247, 248, 316

Cotahuasi Quadrangle (topog. sheet), opp.
p. 192

Cotahuasi Valley, geology, 258

Cotton, 76, 116, 117

Crest lines, asymmetrical, 305-313

Cretaceous formations, 247-251

Cretaceous fossils, 323

Crucero Alto, 188

Cuzco, 8, 10, 21, 52, 62, 63, 92, 102, 107,

193, 197; railroad to Santa Ana, 69-70;

snow, 276; view (ill.), opp. p. 66
Cuzco basin, 61, 62, 154, 251; slopes at

outlet (diagr.), 185

Deformations. See Intrusions

Derby, Orville, 322

Desaguadero Valley, 193

Deserts, cloudiness (diagrs.), 137; rain,
138-140; sea-breeze in, 132; tropical for-
est, 36-37; wind roses (diagrs.), 136

Diagrams. See Regional diagrams

Dikes, 223

Drunkenness, 103, 105-106, 108

Dry valleys, 114-115

Dunes, 114, 254; Majes Valley, 262-267;
movement, 132; superimposed (diagr.s.),
265

Duque, Senor, 78

Eastern Andes, 204-224; regional dia-
gram, 22

Eastern border, climate, 147-153

Eastern valley planter, 3

Eastern valleys, 68-87 ; climate cross-sec-
tion (diagr.), 79

Echarati, 10, 77, 78, 80, 82; plantation
scene (ill.), opp. p. 75

Ecuador volcanoes, 281

Epiphyte (ill.), opp. p. 78

Erdis, E. C, 158

Erosion, 192-195, 210, 211, 305; see also
Glacial erosion; Nivation

Erving, Dr. W. G., 13, 101, 316, 317

Faena Indians, 75, 83-87

Feasts and fairs, 175-176

Ferries, 147

Fig tree (ill.), opp. p. 75

Floods, 151

Fog, 132, 139, 143; conditions along coast
from CamanA to Mollendo, 144-145; see
also Clouds

Forest dweller, 1

Forest Indians. See Machigangas

Forests, clearing (ill.), opp. p. 25; dense
ground cover, trees, epiphytes, and
parasites (ill.), opp. p. 155; moss-
draped trees (ill.), opp. p. 24; moun-

330

INDEX

tain, 14S-153; mule trail (ill.)) opp. p.

18; tropical, near Pabellon (ill.), opp.

p. 150; tropical vegetation (ill.), opp. p.

18; type at Sahuayaco pll.), opp. p. 90
Fossils, 245, 321 ; list of, by geologic

periods and localities, 321
Frankland, 278, 309
Frost line, 56-57

Garua, 132

Geographical basis of revolutions and of
human character, 88-109

Geologic dates, 195-196; Majes Valley,
258, 261; west coast fault, 248-249

Geologic development. See Physiographic
and geologic development

Gilbert, G. K., 300, 302, 305

Glacial deposits, 268

Glacial erosion. Central Andes, 305-313;
composite sketch of general conditions,
312; graphic representation of amount
during glacial period, 311

Glacial features, 274-313; Arequipa
(sketches), 280; Central Ranges; lat-
eral moraines (ill.), opp. p. 269; eastern
slopes of Cordillera Vilcapampa (map),
210

Glacial retreat, 208-214

Glacial sculpture, heart of the Cordillera
Vilcapampa (map), 212; southwestern
flank of Cordillera Vilcapampa (map),
207

Glacial topography between Lambrama
and Antabamba (ill.), opp. p. 280;
Maritime Cordillera, north of divide on
73d meridian (ill.), opp. p. 281

Glacial trough, view near Chuquito pass
(ill.), opp. p. 208

Glaciation, 64, 271; Sierra Nevada, 305;
Vilcapampa, 204-214; Western Andes,
202

Glaciers, Panta Mountain (ill.), "i))). p.
287; view (ill.), opp, p. 205

Gomara, 34

Gonzales, Sefior, 78

Government, bad, 95

Gran Pajonnl, 37

Granit*', 215-224; are also Intrusions

Grass (ill.), opp. p. 154

Grfgory, J. \V., 205

Ilacendndo, 55, 00
Haciendas, 78, 83, 86
Iliinn. .1., 126, 176, 278

Hendriksen, Kai, 98, 315

Hettner, 205

Hevea, 29

Highest habitations in the world, 52, 96;

regional diagram of, 50; stone hut (ill.),

opp. p. 48
Highland shepherd, 4
Highlands, 46
Hobbs, W. H., 286, 287
Horses, 66, opp. p. 91 (ill.)
Huadquiua, 70, 71, 72, 75, 82, 86, 219;

hacienda (ill.), opp. p. 73; terraces,

272
Huadquirca, 243
Huaipo, Lake, 250, 251
Iluallaga basin, 153
Huambo, 243
Huancarania, 64, 87, 189, 243, 303; view

(ill.), opp. p. 106
Huancarqui, 257
Huari, 176
Huascatay, 189, 242, 243; Carboniferous,

244; fossils, 322
Huasco basin, 275
Huaynacotas, 103, 316; terraced valley

slope (ill.), opp. p. 56; terraced valley

slopes (ill.), opp. p. 199
Iluichihua, 278; alluvial fill (diagr.), 272;

(ill.h opp. p. 67
Human character, geographic basis, 88-

109
Humboldt, 33-35, 286
Humboldt Current, 126, 143
Huts, 103; highest in Peru (ill.), opp. p.

48; shepherds', 47, 48, 52, 55

lea Valley, 120; irrigated and irrigable
land (diagr.), 118

Ice erosion. See Glacial erosion

Incahuasi, 51, 155, 285

Incas,_3a, 44, 4(1, 62, 03, 68, 77, 109, 175

Tnrliarate, 78

Indian boatmen, 13

Indians, as laborers, 26-28, 31-32; basin
type, 63-04; forest, ace Macliigangas;
life and tastes, 107-108; mountain, 40-
67, 101-102; plateau, 40-41, 44-45, 100,
106-109; troops, i)0, 91; wrongs, 14, 102

IngoMiwinibi, 206

Instnnnents, siirviying, 315

Inter-Andean valleys, climate, 153-155

Intcrmont basin. See Basins

Intrusions, deformations nortli of Lani-
br.'inia (diagr.), 243; dcfornial i\e ef-

INDEX

331

fccts on limestone strata near Chuqui-
banibilla (diagr.), 221; lower Uru-
baniba Valley (geologic sketch map),
237; overthrust folds in detail near
Chuquibambilla (diagr.), 222; princi-
ples, 217-219

Intrusions, Vilcapampa, deformative ef-
fects near Puquiura (diagr.), 216; rela-
tion of granite to schist near Colpani
(with diagr.), 216

Iquique, wind roses (diagrs.), 131

Irrigation, 72, 76, 80, 82; coastal belt
(map), 113; coastal desert, 119-120;
lea Valley (diagr.), 118

Islay, Pampa de, 114

Italians, 18, 81

Jagucy, 254, 255, 318

Jesuits, 68

Johnson, W. D., 213, 295, 296, 299, 300

Kenia, Mt., 206, 274
Kerbey, Major, 8, 10
Kibo, 206, 274
Kilimandjaro, 205, 206
Kinibalu, 206
Krtiger, Ilcrr, 157

Labor, 26-28, 31-32, 42-43, 74-75, 83-84
La Cumbre Quadrangle, 197, 202, opp. p.

202 (topog. sheet)
La Joya, 132, 133; cloudiness (diagr.),

134; temperature curves (diagr.), 134;

■wind roses (diagrs.), 135
Lambrama, 90, 92, 285, 316; camp near

(ill.), opp. p. 6
Lambrama Quadrangle (topog. sheet),

opp. p. 304
Lambrama Valley, deformation types

(diagr.), 243
Land and sea. Carboniferous hypothetical

distribution compared with present
(diagr.), 246
Landscape, 183-198
Lanius, P. B., 13
La Paz, 93, 109, 276, 321
La Sama, 12, 13, 40
Las Lomas, 318
Lava flows, 199
Lava plateau, 197, 199, 307-308; regional

diagram of physical conditions, 55;
. summit above Cotahuasi (ill.), opp. p.

204
Lavas, volume, 201

Lima, 92, 93, 118, 137, 138; cloud, 132,

143; temperature, 126
Limestone, sketch to show deformed, 243
Little, J. P., 135, 157
Llica, 275

Lower Cretaceous fossils, 323
Lower Devonian fossils, 321

Machigangas, 10, 11, 12, 14, 18, 19, 31,
36-45, 81; ornaments and fabrics (ill.),
opp. p. 27; trading with (ill.), opp. p.
26

Machu Picchu, 72, 220; weather data
(with diagr.), 158-160

Madeira-Mamor6 railroad, 33

Madre de Dios, 1, 2, 33 ^

Majes River, 147, 225, 227, 266, 267;
Canyon (ill.), opp. p. 230

Majes Valley, 106, 111, 116, 117, 120, 226,
227, 229-231, 318; alluvial fill, 273; date
of formation, 258, 261; desert coast
(ill.), opp. p. 110; dunes, 262-267;
erosion and uplift, 261 ; lower and upper
sandstones (ill.), opp. p. 250; sedi-
ments, 255; snowline, 283; steep walls
and alluvial fill (ill.), opp. p. 230;
structural details near Aplao (sketch
section), 255; structural details on
south wall near Cantas (sketch section),
257; structural relations at Aplao
(field sketch), 256; Tertiary deposits,
253-254; wind, 130; view below Cantas
(ill.), opp. p. 110; view down canyon
(ill.), opp. p. 144
Malaria, 14, 38
Maranon, 41, 59

Marcoy, 79

Marine terrace at Mollendo (ill.), opp. p.

226
Maritime Cordillera, 52, 199-203, 233;
asymmetry of ridges, 308-309; glacial
features, 307; glacial topography north
of divide on 73d meridian (ill.), opp. p.
281 ; pre-volcanic topography, 200 ; post-
glacial volcano, asjnumetrical (diagr.),
306; regional diagrams, 50, 52; test of
explanation of cirques, 303; volcanoes,
tuff's, lava flows (ill.), opp. p. 204;
western border rocks (geologic section),
257; see also Lava plateau
Matara, 99, 316
Matthes, F. E., 286, 287, 289
Mature slopes, 185-193; between OUantay-
tambo and Urubamba (ill.), opp. p.

332

INDEX

1S5; dissected, north of Anta (ill.),
opp. p. 185

Mawenzi, 206

Meanders, 16, 17

M^danos, 114

Mendoza, Padre, 11

Mer de Glace, 203

Meteorological records, 157-lSl

Mexican revolutions, 93

Middendorf, 143

Miller, General, 41, 78, 147

Minchin, 241

Misti, El, opp. p. 7 (ill.), 284

Molina, Christoval de, 175

Mollendo, 93, 105, 117; cloud belt, 143;
cloudiness (diagr.), 134; coastal ter-
races, 225; humidity, 133; marine ter-
race (ill.), opp. p. 226; profile of
coastal terraces (diagr.), 227; tem-
perature curves (diagr.), 134; wind
roses (diagrs. ), 129

Mollendo-Arequipa railroad, 117

Mollendo rubber, 32

Montana, 148, 149, 153

Moquegua, 117; geologic relations
(diagr.), 255

Moraines, 207, 210-211; Choquetira Valley
(ill.), opp. p. 208; view (ill.), opp. p.
208

Morales, Senor, 11

Morococha, temperature (diagis. of
ranges), insert opp. p. 172; weather
data (with diagrs.), 171-170

Morococha Mining Co., 157, 171

Morro de Arica, 132

iloss, large ground. See Yarcla

Moss-draped trees (ill.), opp. p. 24

Mountain-side trail (ill.), opp. p. 78

Mountains, tropical, as climate registers,
200

Mulanquiato, 10, ]S, 1!)

Mule trail (ill.), opj). p. 18

Mules, 23, 24, 94, opp, p. 91 (ill.)

NC'vC', 280-305

Nifio, El, 137-138

Nivation, 285-294; "pocked" Hiirfiicc

(ill.), opp. p. 280
Xortheustern border, toi)ograpliic iiihI

Htruetnral sertioii (diagr.), 241

Ocfolmmba Valley, 79

Ocean currents of adjarcnl waUrH, 121-
122 (map), 123

Ollantaytambo, 70, 73, 75, 250, 271;

terraced valley floor (ill.), opp. p.

56
d'Orbigny, 322
Oruro, 93

Pabellon, 80, 82, opp. p. 150

Pacasmayo, Carboniferous land plants,

245
Pachitea, 37, 38
Pacific Ocean basin, 248
Paleozoic strata (ill.), opp. p. 198
Palm a carmona, 29
Palmer, H. S., 250
Paltaybamba, opp. p. 74
Pampacolca, 109
Panipaconas, 69, 211, 213, 215; rounded

slopes near Vilcabamba (ill.), opp. p,

72; Carboniferous, 244; fossils, 322;

snow action, 291
Pampaconas Kiver, 316
Pampas, 114, 198; climate data, 134-130
Pampas, river, 189

Panta, mt., 214; view, with glacier sys-
tem (ill.), opp. p. 287
Para rubber, 32
Pasaje, 51, 57, 59, 60, 236, 238, 240, 241,

243; Carboniferous, 244; crossing the

Apurimac (ills.), opp. p. 91
Paschinger, 274
Pastures, 141, 187; Alpine (ill.), opp. p.

58
Paucartiinibo, 42, 77
Paucartanibo River. See Yavero River
Payta, 225
Penck, A., 205
Peonage, 25, 27, 28
Pereira, Senor, 10, 18
Perene, 155
Physiographic and geologic development,

233-273
PJiyHiographic evidence, value, 193-195
Pliysiograjjhic principles, 217
Physiography, 183-180; Southern Peru,

summary, 197-198
J'ichuPichu, 284
Piedmont nccunnilaf ions, 260
Pilcopata, 36
rifiipini, 3()

risen, l.'tO; Ciirlxmiferoiis land plaiils, 217
I'iura, 119

Piura River, depth diagram, 119, 120
I'iura Valley, 48
Place names, key to, 325

INDEX

333

Plantations, 86; see also Haciendas

Planter, coastal, G

Planters, valley, 3, 75, 76

Plateau Indians, 40-41, 44-45, 100, lOG-
109

Plateaus, 196-197

Pleistocene deposits, 267-273

Pomareni, 19

Pongo de Mainique, 8, 9, 11, 15-20, 40, 71,
179, 239, 241, 242, 273; canoe in rapid
above (ill.), opp. p. 11; Carboniferous,
244; dugout in rapids below (ill.), opp.
p. 2; fossils, 322; temperature curve
(diagr.), 178; upper entrance (ill.),
opp. p. 10; vegetation, clearing, and
rubber station (ill.), opp. p. 2

Poopo, 195

Potato field (ill.), opp. p. 67

Potatoes, 57, 59, 62

Potosf, 249

Precipitation. See Rain

Profiles, composition of slopes and pro-
files (diagr.), 191

Pucamoco, 78

Pucapacurcs, 42

Puerto Mainique, 29, 30

Punas, 6, 197

Puquiura, 67, 87, 211, 216, 236, 238, 239,
243, 277; Carboniferous, 244; composi-
tion of slopes (ill.), opp. p. 198

Puqura, 250

Quebradas, 145, 155
Quechuas, 44, 45, 77, 83
Quenigo, 285

Quilca, 105, 117, 226, 266
Quillabamba, opp. p. 74
Quillagua, 260

Railroads, 74, 75, 70, 93, 101-102, 149;
Bolivia, 93; Cuzco to Santa Ana, 69-70

Raimondi, 77, 78, 109, 110, 135, 155, 170,
316

Rain, 115, 119, 120, 122, 124-125; coast
region seasonal variation, 131-137;
eastern border of Andes, belts (diagrs.),
148; effect of heavy, 138-140; effect of
sea-breeze, 131-132; heaviest, 147-148;
Morococha (with diagrs.), 173-176;
periodic variations, 137; Santa Lucia
(with diagrs.), 164-166; unequal dis-
tribution in western Peru, 145-147

Regional diagrams, 50; index map, 23;
note on, 51

Regions of Peru, 1, 7

Reiss, 205, 208

Revolutions, geograpliic basis, 88-109

Rhone glacier, 205

Rice, 76

Robledo, L. M., 9, 30, opp. p. 78

Rock belts, outline sketch along 73d
meridian, 235

Rocks, Maritime Cordillera, pampas and
Coast Range structural relations
(sketch section), 254; Maritime Cor-
dillera, western border (geologic sec-
tion), 257; Moquegua, structural rela-
tions (diagr.), 255; Urubamba Valley,
succession (diagr.), 249

Rosalina, 8, 9, 10, 11, 37, 42, 71, 73, 80,
82, 153, 237

Rubber, 18; price, 32, 33

Rubber forests, 22-35

Rubber gatherers, Italian, 18, 81

Rubber plant (ill.), opp. p. 75

Rubber trees, 152

Rueda, Jos6, 78

Rug weaver (ill.), opp. p. 68

Rvunbold, W. R., 321

Russell, I. C, 205 ,

Ruwenzori, 206, 274

Sacramento, Pampa del, 37

Sahuayaco, 77, 78, 80, 83, 179; forests

(ills.), opp. p. 90; temperature curve

(diagr.), 178
Salamanca, 54, 56, 105, 106, 180, 181;

forest, 285; temperature curve (diagr.),

180; terraced hill slopes (ill.), opp. p.

58; view (ill.), opp. p. 107
Salaverry, 119

Salcantay, 64, 72, opp. p. 3 (ill.)
San Geronimo, 276
Sand. See Dunes
"Sand}' matico " (ill.), opp, p. 90
San Gabriel, Hacienda, 316
Santa Ana, 69, 72, 78, 79, 80, 82, 93,

153, 179, 237; clouds (ill.), opp.

p. 180; temperature curve (diagr.),

178
Santa Ana Valley, 10, 82
Santa Lucia, temperature ranges (diagrs.),

insert opp. p. 162; unusual weather

conditions, 169-170; weather data (with

diagrs.), 161-171
Santo Anato, 40, 42, 82, 179; temperature

cun'e (diagr.), 178
Schists and Silurian slates, 236-241

334

INDEX

Schrund. See Bergschrunds

Schnmdline, 300-305

Schuchert, Chas., 321

Sea and land. See Land and sea

Sea-breeze, 129-132

Shepherd, highland, 4

Shepherds, country of, 46-67

Shirineiri, 36, 38

Sierra Nevada, 305

Sierra Nevada de Santa Marta, 205

Sievers, W., 143, 176, 205, 263

Sihuas, Pampa de, 114, 198

Sillilica, Cordillera, 190, 260

Sillilica Pass, 275

Silurian fossils, 321

Silurian slates, 236-241

Sintulini rapids, 19

Sirialo, 8, 15

Slave raiders, 14

Slavery, 24, 25

Slopes, composition at Puquiura (ill.),
opp. p. 198; composition of slopes and
profiles (diagr.), 191; smooth grassy
(ill.), opp. p. 79; see also Mature
slopes

Smallpox, 14, 38

Snow, 212; drifting, 278; fields on summit
of Cordillera Vilcapampa (ill.), opp. p.
268

Snow erosion. See Nivatioii

Snow motion, curve of (diagr.), 293; law
of variation, 291

Snowline, 52, 53, 60, 122, 148, 203, 205-
200, 274-285; canting (with diagr.),
279; determination, 282; difference in
degree of canting (diagr.), 281; glacial
period, 282; view of canted, Cordillera
Vilcapampa (ill.), opp. p. 280

Snowstorm, 170

Soiroccocha, 04, 72, 214; view (ill.), opp.
p. 154

Solimana, 4, 202, 317; glaciation, .307

Soray, 64

Sotoapampa, 243

South Pacific Ocean, 125

Spanish Conquest, 02, 03, 77

Spruce (botanist), 153

Steinmann, 219, 270

StreamH, Coast Ilaiigo, 145-147; physiog-
raphy, 192; are also Water

Structure. See Rocks

SUlbel, 209

Sucre, 93

Sugar, 73, 71, 75, 70, 82-83, 92

Sullana, 119

Survey methods employed in topographic
sheets, 315

Tablazo de lea, 198

Tarai. See Urubamba Valley

Tarapaca, Desert of, 260

Tarapoto, 153

Taurisma, 317; geologic sketch map and
cross-section, 248

Taylor, Capt. A., 126, 128

Temperature, Abancaj^ curve (diagr.),
opp. p. 180; Callao (with diagr.), 126-
129; Cochabamba, 176-178; Cocha-
bamba (diagrs. of ranges), insert opp.
p. 178; curves at various points along
73d meridian, 178-181; La Joya curves
(diagr.), 134; Mollondo curves (diagr.),
134; Morococha, 171-173; Morococha
(diagrs. of ranges), insert opp. p. 172;
progressive lowering of saturation, in a
desert (diagr.), 127; Santa Lucia, 161-
164; Santa Lucia (diagrs. of ranges),
insert opp. p. 162

Tempests, lGO-170

Terraces, coastal, 225-232; physical his-
tory and physiographic development
(with diagrs.), 228-230; profile at Mol-
lendo (diagr.), 227

Terraces, hill slopes (ill.), opp. p. 58

Terraces, marine (ill.), opp. p. 226

Terraces, valley ( ills. ) , opp. p. 56, opp.
p. 57, opp. p. 66; Huaynacotas (ill.),
opp. p. 199

Tcrral, 130

Tertiary deposits, 240, 251-267; coastal,
253

Ticumpiiiea, 36, 38, 251

Tierra blanca, 254, 206

Timber line, 09, 71, 79, 148

Timpia, 36, 38, 252; canoe at mouth
(ill.), opp. p. 19

Titicaca, 101, 170, 195, 321

Titicaca l)nsin, 107

Titicaca-Poop<) basin, 251

Tocate. See Abra Tocate

Tola bush (ill.), opp. p.

Tono, 30

Topographic and climatic cross-section
(diagr.) , opp. p. 144

Topographic and structural section of
nortlioasti-rn border pf Andes (diagr.),
241

Topiigraphic map of the Andes between

INDEX

335

Abancay and the Pacific Coast at Ca-
mand, insert opp. p. 312

Topographic profiles across typical val-
leys (diagrs.), 189

Topographic regions, 121-122; map, 123

Topographic sheets, survey method em-
ployed, 315; list of, with page refer-
ences, xi

Topographical outfit, 315

Torontoy, 10, 70, 71, 72, 82, 158, 220

Torontoy Canyon, 272, opp. p. 3 (ill.);
clifi' (ill.), opp. p. 10

Trail (mountain-side) (ill.), opp. p. 78

Transportation, 73-74, 93, 152; rains and,
142

Trees, 150; see also Forests

Tucapelle (ship), 117

Tucker, H. L., ix

Tumbez, 119

l\inari peaks, 276

Ucayali, 42, 44

Uplift, recent, 190

Upper Carboniferous fossils, 322

Urubamba, 1, 41, 42, 02, 187; village, 70,
73

Urubamba River, 72; fossils, 322; physi-
ographic observations, 252-253; rapids
and canyons, 8-21; shelter hut (ill.),
opp. p. 11

Urubamba Valley, 72, 153, 238; alluvial
fans, 270; alluvial fill, 272-273; below
Paltaybamba (ill.), opp. p. 74; canyon
walls (ill.), opp. p. 218; dissected al-
luvial fans (sketch), 271; floor from
Tarai (ill.), opp. p. 70; from ice to
sugar cane (ill.), opp. p. 3; geologic
sketch map of the lower, 237; line of
unconformity of geologic structure
(ill.), opp. p. 250; rocks, 250; rocks,
succession (diagr.), 249; sketch map, 9;
slopes and alluvial deposits between 01-
lantaytambo and Torontoy (ill.), opp.
p. 269; temperature curves (diagrs.),
178-179; terraced valley slopes and
floor (ill.), opp. p. 66; vegetation, dis-
tribution (ill.), opp. p. 79; view below
Santa Ana (ill.), opp. p. 155; wheat
and bread, 71

Valdivia, Seuor, 161
Vallenar, 49

Valley climates in canyoned region
(diagr.), 59

Valley planters. »S'ee Planters

Valley profiles, abnormal, 305-313

Valleys, eastern; see Border valleys of the
Eastern Andes; see also Dry valleys,
Inter-Andean valleys; topographic pro-
files across, typical in Southern Peru
(diagrs.), 189

Vegetation, 141; belts (map), 123; dis-
tribution in Urubamba Valley (ill.),
opp. p. 79 ; shrubbery, mixed with grass
(ill.), opp. p. 154; Tocate pass (ill.),
opp. p. 19; see also Forests

Vicuiia, 54

Vilcabamba, 06; rounded slopes (ill.), opp.
p. 72

Vilcabamba pueblo, 211, 277, 296

Vilcabamba Valley, 189

Vilcanota knot, 276

Vilcanota Valley, alluvial fill, 272

Vilcapampa, Cordillera, 15, 16, 22, 51, 53,
64, 66 67, 197, 204-224, 233; batholith
and topographic efi"ects, 215-224; canted
snowline (ill.), opp. p. 280; climatic
barrier, 73; composite geologic section
(diagr.), 215; glacial features, 204-214;
glaciers, 304; highest pass, crossing
(ill.), opp. p. 7; regional diagram, 65;
regional diagram of the eastern aspect,
68; schrundline, 302; snow movement,
287-289; snow fields on siunmit (ill.),
opp. p. 268; snow peaks (ill.), opp. p.
72; snowline, 277, 279; southwestern as-
pect (ill.), opp. p. 205; summit view
(ill.), opp. p. 205

Vilcapampa Province, 77

Vilcapampa Valley, bowldery fill, 269

Vilque, 176

Violle, 309

Virazon, 130

Vitor, Pampa de, 114, 318

Vitor River, 92, 117, 226, 266, 267

Volcanic country, 199

Volcanic flows, geologic sketch, 244

Volcanoes, glacial erosion, 311; post-
glacial, 306-307; recessed southern
slopes (ill.), opp. p. 287; snowline, 281;
typical form, 310; views (ills.), opp. p.
204

Von Boeck, 176

Vulcanism, 199; see also Volcanoes

Ward, R. De C, 126, 143
Water, 59, 60, 116, 139; projected canal
from Atlantic to Pacific slope of the

336

INDEX

Maritime Cordillera (diagr.), US;
streams of coastal desert, intermittent
and perennial, diagrams of depth, 119

Water skippers, 17

Watkins, Mr., 317, 318

Weather. See Jleteorological records

Western Andes, 199-203

Whymper, 205

Wind belts, 122; map, 123

Wind roses, Callao (diagrs.), 128; Cara-
veli (diagrs.), 136; Iquique (diagrs.),
131; La Joya (diagrs.), 135; Machu
Picchu (diagrs.), 159; MoUcndo
(diagrs.), 129; Santa Lucia (diagrs.),
167; summer and winter of 1911-1913
(diagrs.), 130

Winds, 114, 115; directions at Machu
Picchu, 158-159; geologic action, 262-

267; prevailing, 125; Santa Lucia
(with diagrs.), 166-168; trade, 122, 124;
sea-breeze, 129-132

Wine, 116, 117

Wolf, 205

Yanahuara pass, 170

Yanatili, 41, 42, 44; slopes at junction
with Urubamba River (ill.), opp. p.
79

Yareta (ill.), opp. p. 6 ■

Yavero, 30, 31, 36, 38, 42, 179; tempera-
ture curve (diagi'.), 178

Yavero ( Paucartambo ) River, rubber sta-
tion (ill.), opp. p. 24

Yuca, growing (ill.), opp. p. 75

Y'unguyo, 176

Yuyato, 36, 38

■V

5 8 -■

SWEUNIVER:

lOSANCflfX.

mrj:

^imims

<=5 /

u- f

"^ [

—

c> -

rjl2QNVS01=<^

■^^/

:2: il?

IJ u J 1 I » J 3 \

•\'

vlOS-AVCn

,!3

irvt:!

%AaV}18IH^^

i 2 /o» ] \ m.

1^1

vlOSAfJC

UNIVERSITY OF CALIFORNIA LIBRARY

Los Angeles
This book is DUE on the last date stamped below.

J.10SANC

*^imm

^OfCAllFi

^<?Aavijaii

^•lOSANCF

> u.

IHV^^ "^/ilJQNVSOl^"

'U'JNVikUl^*^

■^/idJAINll J\U

%ojnv3-:

JiliJhVbUl"^'

V/idJAlNil i\Vv

^Of CAllPUMiA, ^^OFCAl

''^A«vji8n-# ^(?Aaviiaii

=o ==

2 "-

Mi IM

soi^ %a3AiNnjy\v >&Aavjj8iv^'^'^ '^oknym

iiis^^ ^<?Ativaan-i^

!^i 1(5^1

III II

^^Wf•UNlVERy/A

—z o=

vjclOSANCEl^

3 1

158 01064 0919

mo/:

%a3AINn3WV

%JI1V>J0>' '^<!/0JllV3JO'^

5MEUHIVERS'/A ^VOSANCElfj>. .<0F CAIIFO/?^. ,-^OFCAllFOff^,

<riirjNvsm^

%a3AIMfl3WV

lillilii^n.!,M^,?.'.',"^°'0^*L LiBRARy FACILITY

..M, ,...| ...| 1^.

AA 000 751690 9

ER% .^lOSAUCElfj-^

T O

s^nNMIBRARYQ^ s^\MLIBKAKY(9/^

A\U UNIVLKi//,

soi^^ "^/^aaAiNO 3wv^ ^oami^'^ -^^i/ojiivdjo^ ^i:?i3DNvsov^

"^AajAiNrtjwv^

v^lOSANCElfj>.

"^/^aaAiNfijvw

^OFCAIIFO^ ^OF CALIF0/?4^ ^^WE UNIVERS"/^

^^Anvaaii^^ ^<9Aavjiaii-i^'^ <rii30Nvsoi^ "^/^aaAwn iwv'

RYO/T. ^^illBRARYO/.

-^ -^ «i3 1 I/— ^ -^

).jO^ ^^OJ11V3JO'^

.5MEUNIVERS//,

^vWSANCElfX;^

%il3AINn-3WV

^IIIBRARYO/.

55MllBRAftY<9/r^

'^(!/0JllV3JO'^

FO;?/j^ ^.OFCAIIFO%

^WEUNIVER% ^vWSANCElfj>

%83AINn'3Wv

^OF'CA1IFO%

^OFCAllFOff^

'■^ommw^ '^ommw^"^

a
g

/^ - "^

vsMLIBRARYik,

"^/^aaAiNrt-jwv^ ^<!/ojiiv3jo'^

^UlBRARy6k^

c*o

\V\t UNlVtKi/A.

"^/^a^AiNrt-jiW^

v^lOSANCflfx^

j^OFCAlIFOft^

^^OFCAltFO/?^

^5MEUNIVER%

^lOSANCElfXo.

%il3AIN(liWV

^<?Aava8ii^^ >&A«viiaii# ^rjijONv soi^ %d3AiNnjw^

<.1'U

'•f-*."'-! »■:''!«