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-^y

(m mmm of the moose riter basin

WILLIAM ARTHUR PARKS, i;.A.

ho. I

To the Rcrjistrur UMVEnsiTY OF TORONTO, May l.^th. lOOO.

Univi rsity of Toronto

I l.i.ff to report that Mr. W. A. Parks l.as ,,ass«l satisfactorily th. exan.inatin,, i„
<'i.(il,,t;y, his iriajcr subject for the degree of Ph. JJ.

I l.eg also to reconnuend that his thesis, "The Huronian of the Moose liiver
iiasiii, be acce|ited for the said degree.

Yours faithfully,

A. P. COLEMAX,

I'rj/issor of Vtuloijy.

I iTKREBy certify that the thesis above mentioned has been accepted by the Senat.-
of the I n.vers.ty of Toronto for the Degree of Doctor of Philosophy in accor.lance with
the terms of the Statute in that behalf.

JAMES BREBXER,

University of Toronto, June 11th, l!)no. H'Vistrar.

m mum of m moose river bash

Tlio Moose Eiver, enteviiic" tlie south-west aiiiile of Jiunes
lUiy, drains an iinnieuse triaiiiiular area of wliioh the apex is at the
river's mouth and tlie hase stretches from ahove Lake Alutibi to
a point west of Kahinakai>anii Lake. Kaeh side of tliis trianjiU'
is approximately 2."»() miles, and, allowin<>- for sinuosities in the
houiidary, its area cannot be less than 30,000 square miles.

Lx])lorations in this extensiv<> resiiou have not y^t put us
in possession of the minute information desirable. In ISO,", Dr.
]fobert JJell made certain ex])lorations -wliich are described in his
report to the Ceoloaical Survey of Canada in Ks7,'), and at a latiT
date also he was euiployed for several years in this ilistrict. The
results of liis in vest i,i>at ions may be found in the Jieport of the
Geological Survey of Canada for lS.sO-2. .Mr. K. ]>, IJorron like-
Avise made several jom-neys, particularly in ISSl and ]SS2, and re-
ported on his explorations to the Ontario (iovernment.' li\ IMm;
Mr. Alexander Niven was commissioned to lay down the bi'undary
line between ^Xipissing and Algoma, which he extended for one hun-
dred and twenty miles; he. was accom])anied by :Mr. E. Ihirwash,
whose report r n the geology of the region traversed a])pears in the
Iie])ort of the llureau of Mines of Ontario for 1 ^!Mi. This boundary
line Avas continued to the ;Moose lliver in 1S1»S, and a base limi
carried westward from the 120th iiost in IMIii. Lhe writer accom-
panied the two latter ex]ieditions as geologist, and his reports ajipcar
in the Reports of the Lurcau of ^Alines for these years.

With the exception of the above mentioned reports, there is
very little available litei-ature bearinii' on the* region in question.
The southern and maj<ir portion of its triangular area consists of
Laiirentian gneisses and granites crossed by several bands of
niuronian rocks, 'i'lie u]iper part ])resents linu^stones, dolomites
and shales of Devonian and possibly also of Silurian age. The
present paper deals with the JIuronian alone, and more particularly
with the petrography of the series as here exemplitied. For infor-
mation as to the general geology and topograjihy, economic resources
and other points, reference must be made to the reports above cited.

1 lii'pnrt of E. V. Itorron, Stipendiary Maiiistrate, on Part of the Basin of Hiuhon'it
Hoy. Toronto, 1883.

Tlio tOTin "TTrroiiiiin " is api)lio<l in this paper to nil the rocks
al)()V(' the Lniireiitian aii<l beneath the lowest fossiliferous strata.
In this sense the expression is made to inclnde roeks oi variou- aiio
and ditTerent petroi>ra]ihieal natnre, sueh as J.o^an's oriuinal
llnronian, Lawson's Keewatin and ( 'ouohouehiiig series, the Ani-
niikie and Xepifi'on formations, the i>ray\vacke and associated roeks
of the Sndlmry reji'ion and the various schists, altered erni)tiv(s
and crushed li'ranites characteristic of wide areas in northern On-
tario. In the reii'ion under discussion the Iluronian is representcfl
hy a great variety of schists, presumahly of clastic oriain, and hy
others of altered eruptive nature, clusely associated with both acid
an<l basic eruptives in various staaes of decompositio'i. N'o lime-
f^tones or saudstfrnes occur anywhere in the reffioi; examined by
the writer, altluniiih Dr. Bell reports tli(> former rock just south
of the heiii'ht of land near the Montreal Ivivor, and Mr. Ijurwash
also refers to it.

It is in regard to the various schists that the great difficulty
of determinatiou arises. To establish n fixed uomeuclature for
these is almost impossible, as their varieties of colour, structure and
texture are practically iniiumeralile. Jn a dislanco of twenty feet
no less than seven distinct varieties were counted on one occasion.
On the other hand, to pass by these rocks with a mere description is
altogether unsatisfactory, as megascopic descrijitions by different
observers might leave considerable doubt as to the identity of similar
cxjiosures. For exam])le, the sanu' rock is describiMl as " dark
(luartzite," " dark gray siliceous schist," " quartzose schist," f tc.
To the trained scientist these terms, while not ])etrograi)liically
synonymous, are sufficiently suggestive to recall the rock in ques-
tion. In imblications, however, intended for the guidance of pros-
pectors, this method causes great uncei'tainty. For economic i)ur-
poses, it would suifice to establish the fact that, for a particular
region, a certain varietv of rock was ore-bearing, leaving the ques-
tion of its origin to more scientific ol)servers; luit there are too many
gradations to render such a classification of any real value. It is
only on the basis of origin that a satisfactory arrangement can bo
effected.

The petrogTaphical peculiarities of the rocks encountered will
first be described, with little or no reference to geographical posi-
tion, and afterwards the great Iluronian areas will be outlined and
the location of particular species indicated.

nil tlic rocl<s
Pci'ous strata,
f variou- aiic
lu's oriii'inal
ic?, the Aiii-
ociatcd rocks
•('(I (■ni])tiv(s
lortlicrii Oii-
s ro]iros('ntcfl
•iuin, and l)y
itli both acid
1. Xo limo-
exniiiiued by
■Is just .«outli
Mr. liurwasli

'oat difficulty
'nclntiiro for
structure and
■ twenty foot
one ocensi(Ui.
description is

by ditt'ercnt
ity of similar
ed as " darlv

schist," ftc.
rograi)hically
rock in qvies-
iance of pros-
cononiic pur-
' a particidar
inc the qiies-
are too many

value. It is
■ment can bo

ountered will

raphical po*i-

outlined and

All rock^ are either ern]itive or sedimentary in ori,i>in, l)Ut
sueli a primary division is uselos in tlie present instance, where
dviiamic' metaniori)liisni has ohliteratiMl the dividinii' line and in-
duced resemblances -which forci' vork- of ditl'ereiit origin into the
same grou)) on account of sinularity of structure. Xi'Vertheless
it is to oriu'in that we nm>t look in deeidinu' the more nunutc
divisions.

AVe have therid'ore: —
T. Tnaltered eruptive^.

]]. Much metamorphosed eruptives and elastics, p;encrally

schistose in structure, which may be endiraced in the

term srliisl.

Aniono,' unaltei'eil eruptives are included all those rocks of

primary ip-noous origin, in which tlu- oriiiinal -tructuro and mineral

constituents are unaltered or but slightly att'ected. They may i>e

grouped and will be considered in the foUowin*;- order: —

(1) Acid or potash-felds)iar rocks: Clraiiilc, siioiilc, tiuii'ifc sye-

)iile, qwiriz porijlii/ri/.
{'2) Basic or plagioclase rock: Diorile, dinhnsc, oUviiie dinh^isr,

ijahbro, basalt, (Uin/ydaloidal Ifiji. /ii/rcri'iiih'. unovliinsih'.
Cininllc. — This rock, in an unaltereil condition, plays but a
subordinate jiart in the geoloiiy of the district, as far as the \\\\-
roinaii is concerned. "When present in this formation it is p'uer-
ally in the form of narrow dykes, conforming: to the strike of the
schists; the district described as the "second area" is mor(> remark-
able for these rocks. ^Iusc(.>\ire, horidilende and biotite jiranitcH
have ])een observed; in all eases they are typical and reipiirc^ no
further notice, l.ariio masses of pranite, in some cases probal)ly
eruptive, in others representina" the non-laminated portion of the
Laurentian matrix, are common in manv parts of the reii'ions of that
ajie. According' to the theory of Dr. Law-on ' the ^raidtic portion
of the matrix wonld be distant from, and the ji'neissoid portion near
to the iriu'oinan contact. On this assumption much of the i>ranite
observed must be eruptive, for a loss of lamination on approaching-
the contact is apparent in manv places. Some of these masses are

' Ueimrl on the Geoloinj of the Uatiiij Lake Region. (Report Geol. Sur\'. Cun.,
1H87, im«e 112.)

mapped ns oniptivo cvanito bv T>r. Ilcll. It i> not within tlio icopo
of tliis ])iip(M' to discuss tlic jHtiut. {Vov localities sec pages l'l', -J'-j,
iir>, ■2(\, 27. :)(». :;i, ;!;; and :54.)

Si/('nlh\ — This viK'k also i> not widespread, typical examples
Ix'inii' very few. One mass occurs about Hfteen miles up the I'dack
Itiver and shows altered honddende and feldspar, the cliaractcr of
the latter beini>' somewhat hard tui deternnne in the specimen
obtained; ])ut as the jicneral ficdd appearance is decidedly syonitic,
j^nil the niicroscoix' reveals scarcely any trace of striation in the
f(dds]iar, it is concluded that the rock is syeinte. altliouah it ]iro-
bably contains some idat-ioclase. In addition to this exi)osur<- and
some narrow bands associated with the s(diists, all the syeiute is,
like the li'raiute, blended witii liiieiss and syenite a'ueiss and must be
classed as LaiU'entian. (For localities see pat^cs -J'.) and :!(i.)

Aiif/Hc siimHc — Th(' mass of eruptive which crns-e.- tho
Abitibi Kiver, forming' the Lobstick and other rapids as well as the
Great Canyon, is represented at its upper or southern margin by a
rock of this nature, which continues with some variations for two
or three miles. It is intersected by snuill dykes of tine black dia-
base, Avliich present some beautiful exami)les of miniature faulting'
and branchinji'. At the Lobstick Poi'tage it is somewhat schistose in
places and much altered, showinc,- numerous red iiarnets, a little
quartz, considerable oi-thoclase and some i)hi,uioclase with briiilit
green aui>ite. At the Oil Can Portaue and above it, a section shows
fairly lariie crystals of autiite in a somewhat tln(>r and mosaic-
like mass of orthoclase Avith a little (luartz and phijiio(dase. The
aupite is. in many places, almost entirely altered to fibrous horn-
Ideude, fiakes of brown mica, i>-arnet and maji'uetite. This rock
presents a gravish-black, somewhat speckle<l apjiearance with evid-
ence of flow structure or secondary lamination. In its rnoiv altered
parts r.re seen sphene and mellilite. (For localities set ])aiie ■")•■).)

Quartz porphj/ri/. — This rocdv docs not occur in a iiood state of
preservation, but in an altenMl and schistose condition it is very
common; in order to carry out the classification adopted, it cannot
be inchnled here but will receive consideration under the schists.

Dioriir. — Typical diorite is composed of distinct anhedra of
liornblendc and plagioclase, forminif a Inird, nnissive and sonorous
rock. In some cases the individual minerals reach a size of several
inches, giving the rock a mottled appearance. From this coai'se

'itliin tho scopo
(• piiiics -J-J, i':j,

■pical oxaiiiiilcs
■s up the Black
lie c'liarat'ter of
tlu' spccimoii
idciUy syoiiitio,
triation iu the
Itliouiili if ]iro-
s 0N])()snrr and
tlic sytMiitc is,
iss and must be
) and :!0.)
A\ crosses tlio
< as well a.-i the
'11 margin hv a
iatioii^ for two
hue blaek dia-
iature fanltiuii:
Imt schist(i>;e in
arnet-i, a little
•e with hriiiht
[t section shows
r and niosaic-
g'ioclase. The
) fibvons lun'n-
te. This rocdc
nce with evid-
's more altered
ee ])ace 'V-].)
a good state of
ion it is very
ited, it cannot
■ the schists,
ct anhetlra of
' and sonorous
size of several
)ni this coarse

variety all gradations are seen down to that composed of individ-
uals (it luieruscdpic si/.e. The tiuer examples oii fresji fraetm'o
still shuw the ery>talliue structure, but the nmttled appearance i-i
(■iitirejy lost, ])artly (aviug ti. the tiiieness of texture, but pcrlians
nidi'e in (•iinseipieuee of diseojoi'iirion of the feldspar. Thi« ivp-
is common ;in<l fairly line exainples arc the rule, no \ery coar-e
diorites being .-eeii in the region.

Diorite occurs in large dykes traversing the country rock in
all ibrections. and also fre(|nently in irregular masses fonnini:' riie
summits of hill>: in some instances the intrn-ive mass lia^ lifted
the country schists to the suniinit of the hill, while the diorite
a])))ears on the Ihmks. By far the ninst general manner of oeeur-
renee is in bands of varying thickness, <'onfornKdile with the -trike
and dip of the s(diists, whiidi is avnerallv at a high angle. Tliesa
thin hands are invariahly iine-graineil and almost black in colour.
31any of them towards their borders have entirely lo^t the cry-tal-
line structure and are honiogi'neous to the naki'd eye; the micro-
scope, however, reveals some traces of crystallization in ill-forine.l
hornblende and magnetite crystals, due, of course, to the more rapid
cooling of the exterior of rue mass. An imjiortatit con-idera-
tion now confronts us. \vv these interbedded diorites contempor-
aneous with the schi>ts, are they sul.secpient eru])ti()ns, or are tho
schists themscdves derived from the diorites^ it is in-obable that all
these cas(>s occnr. The diorites can rims be divided into thre(>
classes, (T) massive eru])rives, (2) contemporane(His diorites, (:;)
diorites passing into diorite schists.

(!) The class of massive eruptives can be recognized by a
distinct crystalline structure nearly always increasing in fineness
towards the borders and on. holh sides. All the irregular ma^sc:^
that form hills, the large dykes crossing the country r(xd-:, and nianv
of the interlaminated sheets slmw this peculiarity. As far as the
last variety is concerned, the bilateral symmetry of the mass can 1 o
accounted for on no other assumption than that of snl)se(pieut in-
jection. The accessory evidence of a sheet of diorite breaking acro.-s
from one plane of stratification to another has not been observed
heVe, although it is wcdl known to occur.

(2) Confem])oraneons diorites a.re generally less crystalline,
more easily weathered and more inclined to show irregularities
of colour and structure. If these rocks were oriainallv overflows

tlicv iim-t liiivc ciiiiiulidiifod n.~ (liiil)a»('?, l)Oi'ii\i>o diorito is jroner-
all.v (•(iii^idcnMl iis cssciitiallv phitoiiif. On the as.sniii]itiiiii that tin*
(•rijiiiial iiiaiiiiia \va> covered liv (dii-tic 'Materials wliiidi eveiit>ially
lieciiiiie iiietaiii<iritli(><e(I into Mdn-ts. we should eN])eer to tjnd a
ditVereiice lietween the lower iinil the \i))pei' surfaces. This ci)U-
dition has l»een oliserved hy no nieaiis constantly. A sulHciont
nundier, however, on e\aniinatif>n ^a\(' convincini:' evidenco of
their contein))oraneous luitnre, and it -eenis advis;dile to inidiide in
this cla^-s most of the narrow hands, ])erha|)s all in whi(di no hilateral
arranuenient can he detected.

(.'!) Jiocks of the thiril (dass. /•/',:., diorites pas.^iiiii' into diorit(!
schists, consist of ordinary diorite towards the centre of th(> layer
hecomiiii:' more and nioi-e ^(dnstose outwards, find tinally t'adin.ir
away into other schists without any distinct line of dt'niarcation.
This tyi^e of rock is doul)tles> the result of intense nietamurphism,
ami, while easily rccogni/ed, affords very little information as to
oriuin. While they seem to ho l)est i)lacetl in n (dass l)y thomselvos,
th;'V are more jirohahlv dei'ived from tlie second than from the fir-t
aTouj) on account of the difforence in composition towards tlio
l)or(h'rs. Tlie outer parts show much more (piartx than llio
inner. This co\dd hardly result from metamorphisni alone; there-
fore it is concluiled that tliey were more or less mixed with aciil
cdastics, \vliicli would point to a more contemporaneous origin.

Any of these diorites mav jjresent varieties, hut more especi-
ally those of the first class. While typical diorito consists of horn-
hlende and ]daiiio(dase, the former initrodient may bo replaced
wholly or in part by black l)iotite, fiiving a rock known as mica
diorite, or quartz may occiir, fonniuii' (pnirtz diorite. ]iotli these
varieties are found in the rejiion, as well as quartz mica diorite
(tonalite). The latter genorallv has a pink feldspar and nuicli
resembles cranite; a section to ascertain tlie nature of tlie feldspar
is the only sure means f»f determination.

The passage oi dioi-ite into diorite schist and the so-called
" greonscliists " is a suVqect of much eontrovei'sy. The meta-
morphisni is accompanied by various ])henomona of alteration, as
changes in texture, softening, change of colour, alteration of horn-
blende to actinolite or chlorite, or even to hematite, magnetite, etc.,
alteration of feldspar to epidoto and saussurite and in many places
to calcite. These various changes have produced rocks which arc

iDi'ito IS ffoncr-
iptiuii that till-
licli c'vciitually
pcct tn liiid ;l
f^. Tliiri coM-
A .^utHcioiit

^ CXiilcilCO (if

-' t(i iiicliido ill
fit ii<» liilatcral

lii" into (.li(>rit(;
(' of tlio layer
Hnally tadinii'
■ <l('iiiar('ati(in.
ictaiiiurphisin,
niiatioii as to
)y tlioinsclvos,
from the first
towards tlio
•^y. than tlio

alone; tlicre-
<('<1 witli acid
Is origin.

more especi-

isists of horn-

' be re])laee(l

lown as mica

]jotli these

mica diorite
II' and mncli
" tlie fehlspar

tlie so-called

The meta-

^Iteration, as

tion of hom-

ignetite, etc.,

many places
vs which arc

in iiuiiiy instances almost iini)ossiiilr to reconnize, ami mn^t l.o
named more or less hy analouy. Tlicy an- imdnded under tli-'
s('hi>r- and a more detailed dcM-ription will lie i-iveu later. (I'lir
} loealiii,.- see ].ajies i';!, i',"), J7, l'>. ;;(i, ;;i, ;;j, ;;:; .,,,,1 ;m.)

PkiIhisi'. — This rock is hv no mean^ a-> e(jmmon as diurito
and il-< examples -eem to liejoni: to ditVei'eiit periods nt' injection.
'J hose of -imilar auc to the diorites and schists are ii'eiierally much
altered; while a second >eries, of api»arentlv later aii'c, hetter retains
the oriiiinal nature. llock< of the hitter type occur in narrow dyke^
cro-^iiii:- rhe countiy mek in all directions; they are particularlv
iioficeal.le in the eruptive i-euion of the .\hitil>i Canyon. These
helts aiv uniformly ver\- line-iiraine<l ami hhick in coluur; they
commoidy show a difference of texture at the i>eriphei'y, which
weathei-s smooth while tin centre has a nioi'e punctate.! api)earance.
(See pa,uc< -J-J, -j:',, lil. ijC. and :;."..)

Oliriiic (litili<i.^r.—]A[y<j:v li.iuhhr-- of ihJ- ''nek were foiiml at
the Sextant J^lrtal;■e in the Pevouiau area, a;.'! must have lii'cn
derived from the nei,iihliourin,a' lluroniau, although not -een //(
sihi. A section shows the n>nal diahase -i uctnre with n, ■ dies of
apatite and irrejiular patches of olivine. \.nich is nunh altered to
mn j;;r: ite.

Chihhro. — ""["he niost characteristic examjilis df p'althro occur on
the northern jiart of the Ahitihi Canyon, and even there it can
scarcely he considereil typical. The he-t eNpo^urc^s ar,. seen at the
deepest part of the i>ori>e, where the clift'< .m- 100 feet liii;h ami of
a dark massive apjicarance. Cnder the nucrosco]ie the auiiite is
seen in distinct cry>tals hut little (lec(»mpo<ed. The. feldspar is
represented hy hoth varieties with the phmioclase in exce-s. wIkmicg
iti may he termed uahhro, altlionah further south it ])asses into
anjiite syenite. (See pa,<>e ",",.)

BoKolf, (i)iiiff/(kih)i(Jal fnip, pi/nirenllr and anoHlinsilr are of
such rare occurrence that suliicient reference to them will he found
in the notes of distrihntion. (See pages -j:] and :!:"'..)

'I he whole serie- of Iluronian rocks not inchided under the
unaltered eruptives it i^ proiioseil to j>ronp together as schi>;ts,
although tluy may not always ]n'es(.iit a schistose structure. Tiu>
nse of this term is at the hest very uncertain, as is seen hv the
interpretation placed ui)on it hy Professors Irving, Chamherlin aiul
Van ITise. "Almost any non-fossil if orous rock presenting in sonic sort

a stratiform structure, and more compact ami indurated than i? usual
Avith post-avchacau strata, lias Ix-en six.keu of as a crystalline schist.
I'he near approach of cc-rtain foliated fragniental deriva-
tives to tyi>ical crvstalline schists— indeed their oi-adation into un-
distinjinishable, if not identical, forms, and the passaii'e of massive
evn])tives into schistose phases — would render very dilhcnlt a
shari)ly limited consideration of the typical crystalline schists.'' '

In this hroad sense our roi-iou is for the most part made up <d'
such derivatives, which may be divided into two :r.ain groups, (1)
tliose Avhose origin was probably eruptive, (-I) those whose origiu
was probably clastic. The dilhcnlty in di-tinouishing these two
classes is very iireat, as they ])ass imperceptibly into each other and
as a mass of certain ultiniiite composition whether originally enip-
tive or dejiosited as a fragniental may give rise to the same rock.
Professor Williams says, " IJetween undoubted massive rocks ren-
dered schistose by pressure on the one hand, and fragineiUal tuffs
which have been more or less c(>m])letely solidified by the sanu'
aa-encv on the other, then; mu^t therefore be rocks whose original
form must always remain uncertain." "

Tn this connection see also Irvinsi-, Chamberlin and Van Ilisc,
•'Tlie greenschists have buon derived by the modiilcation of original
oruptives and present a degradatlonal development which may bo
hioked upon as ottering a contrast to the constructive developmenr
of the crystallines built up from clastic originals." ■'•

It will therefore be evident that any attempt to classify tlusi'
rocks must prove in some manner unsatisfactory; various author-
will adoi)t diiVerent methods, and some overlapping and unccr-
taintv will always exist. The above mentioned authorities classify
the Lake Superior schists thus: —

I. Eruptive derived (metamoriiliic) crystalline schists.
IT. Tutf deriviMl crystalline sdasts, which were develojii 1
from igneo-fragmental mat(>rial.

III. Clastic derived crystalline sidiists, which were develop. ]
from fragniental rocks by secondarv growths of the constitue: t
crvstalline fragments.

'Coiiiiit's Geolofiique Internatioiuil, KtUilci sitr les Schisten Cristdltins. L^
dres, 1S8S, pa-^e i)'2.

- U. S. Geological Survey, V.ulU-tin G3, 18fl0, pajje IS;?.

■'CoiiKit's Geolotsique International, WiK^f*- siir Zfs Schiates CrishiUin». Lo
fires, 1888, page 103.

tccl than i? u?;ual
■rvstalline st'lii?t,
iginental doriva-
adation into uii-
ssaii'o of massive
very diliioult a
lino scliisis."' ^
part nuide up <>(
r.ain SiTonps, (1)
38C whose orip,in
ishin<i' these two
o eaeh other and

originally enip-
3 the same rock,
assive rooks rer.-

fragnicnlal tulTs
ied by the sanu'
vs whose originid

n and Van Ilise,

cation of original
it which may l>e
tive development

: to (dassify tlusi'
; various author-
iping and uncer-
uthorities classit'v

10 schist^,
were develojn 1

h were develo]ied
■ the constituoi.t

ften CrintciUina. L

ten CristaUins. Li

(incriiui clienucul, organic and clastic agencies joined.

Professor Dr. AlLuTt lleim, after showing the difricnlty of
classification and sniiimari/.iiiii' tlie various etfects of dynamic
motamorphism, savs, " I)i(> rx'^clialTenheit dor krystallinischen
Scliiefi'r in den Al]ieii ist vicdfacdi dnndi den (ieliirg-stannnii>prozo-s
verlindert worden. rrsi)riing!iclies nnd mochanis(di spiiter (owor-
denes siiid sidir oft nocdi uar nicht von t'iiiander /u iiiiterschei-
deii." -

Dr. Andrew Law>'in cla>siti(>s the Keewatiu series of the Lake
f the "Woods thus: —

of the Woods thus: —
I. Basic N'olcanic

asic N'olcanic:

Altered diahaso and galihro, massiv(^ and schistose with

associated amidiiliolites or <li(irite> and hnvnlilende schists.

II. Acid Volcanic:

AUered (piartz porphvrie^, felsite sehi.-ts, -ericire -chist<,
l>ii]'))hvroids, etc.

III. Volcanic Clastic — pyrocdastic:

Asji Ix'ds. many graywackes, tuft's, and agglumoratc-,
hoih liasic and acid.

IV. Detrital — epiclastic •
Conglomerates, tpnu'tzitos, clav slates, micaceous slates:
soft, gray, glossy hvdromica schists; with chlorite schist^,
mica schists, and certain tine-grained gray gneisses, or
ratlier feldspathic mica schists.

iii.vti -v 111.-1.7, (lIUl HlliUM luie-jii

ratlier feldspathic mica schists.

A . (iai)l)ro, ser])ontine and granite.''
\r.,,,,. ,.4! tl.„ . .1.:, .^^ .J} '_

Alany ot the sclii.sts of our region are quite comparalde ti.
LawsoiTs series, lint many of Lis mendiers are alnmst or eutirelv
lacking, notahly the conglomerates, agglomerates, serpentine-, and
g'ra\ wackes.

It is not propo.sod here to deal with theoretical coiisidevatioiis
as to the origin of the various represonta lives. Smdi ])oints can
onlv 1)0 det ermined hy a detailed study of a more restricted area

'/'"■''• P- lOJ- •-' Tl,i,l, p. 20.

■ C'on^res G.-'oioyiqne Internatioiml, Ktmh's .vir Ic.o S,-hi,t.:^ Cn.it„!lhi< Lon

rtree, IMSw, ,nif<e 71. JU;,ort on tlw Geohunj of Il„iiu/ l,,il:e lle.non. (Reuoit Geol

Surv. Canada 1887, Part F, page 67 i7 st(y.) ' l"«i'"'t ^eoi.

than that now under cliscus^inn. The intention i? rather to describe
the various sehists and to name and liTonp them aeeonhnff to their
present ])eonHarities, and, in view of tlie donht attendinji' their
C)rii>:iii, to c'm])hiy tliat eviihiice onlv when the roek scfUis to l-e
anaU^ii'ons to some described In- oood authorities. From this point
of view the following' tabk' will iiive an outline of the method
adopted: —

I. S(diists of eruptive orii>'in:

(a) The ''green_schists '' and diorite schists.

(b) Altered ]iorpliyries an<l porphyrites.

(d) Hornblende and biotite mica schists.
IT. Schists of fraaniental oriiiin:

(a) Pyroclastic schists and ash schists.
(h) Quartzites.
(r) Clay slates.

in. Schists of doubtful oriiiin or belongino- in part to both
the abi>vc:
(o) (Juartzose schists.
(h) Sericite and chlorite schists.

I. Schists of Eruptivk Origix.
(a) The " f/rcen.^chisla '' and diorite S(diist.s. — As indicated in
the descriinion of diorites, that type of rf)ck ]»asses nradually into
diorite schist. retainin,<>' its mineral structure and merely bec'omin.u'
schistose by dynamic etl'ects. These diorite schists are quite char-
acteristic an<l iicf<l n,, cnmment; thcv are widely distributed and
easily recoi>nized, if not in the field, at least by the examination
of a thin section. The "stdiists" are doubtless eruptives which
have been subjected to more intense metamorphism and while
jicnerally occurrino- i„ narrow bands are sometinu's massive and of
considerable extent. They do n,,r commonly invsent a schistose
structure in the hand speciuKMi, and verv rarely can such a struc-
ture be made out under the microsc(jpe. In the'tield tlH> weathered
surface is a shade of dirty nroen; it .uenerallv shows a somewhat
punctated a])])earance and fre(|uently exhibits >mall whitish specks.
(These must not be confused with the lari-'er and more ani-ular
blotches seen on manv altered porjihyrites). The freshlv broken
surface is rather uneven, greenish to black in colour, and shows a

tlior to dopoi'ibe
'(ivdiiisi' t(i their
atrendin,!i' their
.'k sei'ins to l-e
''mill thi?i point
of the method

1 part to both

Ls indicatrd in
.uradually into
rely beeoniinu,-
ire quite ehar-
istributed and
e examination
uptives which
!im and whih'
na>sive and of
nt a sehisto.-e
sncli a struo-
tlH> weathered
'^ a somewliat
^•hitish ^^peckg.
more an^nhir
reshly ])roken
, and shows a

pomewliat silky surface, which under the liand ^lass is seen to be
distinctly ratUal in structure. Microscopic sections are decidedly
unsatisfactory, showiiiii' generally but an indistinct dirty mixture of
kaolinized and saussurized feldspar, a very little ipiartz and liyht
^reen liorul.lende and chlorite, with accessory pyite, hematite,
magnetite, ,earnet. mica, etc. Some of these rocks very much
resemble the darker varieties of quartzose schists to lie subsequently
described. In the field they may be distinguished from th(> latter
rock by beini-- more easily abraded l)y the hammer, and l>y the fact
that they do not show the same tendency to break into rhomboidal
blocks.

This rock is one of the most frecpunt occurrence and ])rol.ably
constitutes the bulk of the first or iireater Jluroidan area, the limits
of which will be indicated in the second i)art of this paiu'r. The
Avhole question of the nietamorpliism l)y which theso rot-ks were
produced would fill volumes. As here cxemiililicd rluy are aualo-
,U-ous to the so-called " iireen Jhiroiiiau schists," and probably
identical with the series described by Professor Williams in tlie
"Greenstone schist area of Michii>an," where he says:

"There seem to be only three different ways of explaininij,'
the facts as th(>y are idainlv and al)uiulantly manifested in each of
the several poiiit> examined on the ^lenominee Kiver, Wi' may
supi)ose, as did Foster aiul Whitney, Whittlesey and Crcdner. that
the schistose pditions of the rooks exposed at these several ])oint8
are more or less perfectly metamorphosed sedimentary material,
Avhile the more massive ]iortions represent intercalated beds of
eruptive oriiiin. AVe may ima.iiine on the other hand, as did
Romiiiiier and P.rooks, that all of these rocks, includin- the most
schistose and the most massive iihases. are ))rnbab|y altei('(l sedi-
mentaries, supposing with Koniiniicr that the more ma-sive kinds
are mercdy the same sedimentary material fus<>d by the iiitensitv
of the metaniorphosinii' action so as to lose all trace ,,f the original
stratification, or admittin-:- with IJrooks the iiossibility. thouo-h
i;reat imj.rebability, that some of the more massive phases, like the
pabln-o of Sturiicoii Falls, are of eruptive oriain. Finallv. we may
imaiiine that all phases seen at these several places reiu-esent
material of eruptive orii-in wliost^ stratiform structure is due to
sccnndnrv rlynamic nconoios. (Trvin^.)" '

' U. S. Geological Survey, liulletin 63, 1890, page 0(!.

Here Professor "Williams nn(lou1)te(lly includes other schists
than the variety now under dii^eussion, but from the description3
this particular rock must form a larae part of his series.

The theor\' that the massive diorites are intensely altered sedi-
ments is utterly untenable for this region; for pi'oof of this the
reader is referred to the remarks already made regarding the
more massive diorites, to the bilateral aiTangemeiit of many of the
bands, to the fact that in many instances they abut with a sharp
line of distinction against entirely dissimilar rocks, and further that
an enormous number of similar belts of diorite traverse the neigh-
bouring Laurentian gneiss, notably on Jlay Creek, Misanabie Lake,
Little ]\Iisanabie Lake and Kiver and the Laurentian area around
the Pishkanogama and ^lakozenda or Trout Kivers. Granted then
that the massive variety is eru])tive, the freciuent and beautiful
gradation into rocks of this type so constantly seen is suflftcient
proof that they liad a innmary erui)tive origin. (For localities see
pages 22, 28, 25, U), CI, 32 and 33.)

In this connection mention must be made of the altered dia-
bases. Ivocks of undoubted diabase origin are rare, but the possi-
bilitv nnist be admitted that nuiny of our greenschists are of that
nature. The ])roof of this in manv individual cases can never be
obtained. IIowcA-er, greenschist, showing 710 trace of pyroxene
but exhibiting undoubtedly the structure of diabase has been met
with, notably on Kamiskotaia Lake. This rock is grayish green in
colour, not extremely hard, and only by the microscope is its dia-
base origin revealed; the feldspar is almost entirely altered and the
augite changed to almost colourless hornblende and chlorite, but
the ophitic structure is well ])reserved.

(h) Altered purphj/ries and porph/rites. — As already men-
tioned, unaltered rocks of this type are absent, but a large series of
altered representatives are met with. Schistose quartz porphyries
present almost invariably a light gray or white surface and Verv
frequently the quartz individuals stand out on the exposed surface
by the weathering away of the more decom])osable, constituents.
Concerning the origin of these rocks Professor Williams says:
"They contain small porphyritic crystals of feldspar and quartz,
and a considerable amount of sericite or hydromica. . . . .
Piocks of this general type have a M-ide distribution and have ar-
rested the particular attention of petrographical investigators. In

>s other schists
lie dcscriptiong
Tories.

ily altered scdi-

x>f of this the

rc'ii'iU'diun' thi'

ii iiiauy of the

t with a sharp

tid further that

erse tlie neigh-

lisanabie Lake,

111 area around

Granted then

and beautiful

Ml is suittcient

ir localities see

he altered dia-

but the i)os.si-

sts are of that

1 can never be

of pyroxene

has been met

ayi^h green in

'oj)e is its dia-

Itered and the

. chlorite, but

already men-
large series of
I'tz porphyries
face antl x'ory
cjjosed surface
I constituents,
niliams says:
r and quartz,

and have ar-
stigators. In

some cases they have been conclusively proved to be the product of
the metaniorphism of fragnicnral rocks— either tutis or true m'.H-
'"'''^^^— ^'''i'^' "I other cases they have resulted from tlie action of
great (lynauiic forces upon massive rocks of a correspondiui;- cou-
iMi-mation, //■., quartz i.^rphyrics. Wlien it is possible to trace
M-ith certainty the origin of these rock< to stratified deposits tbev
aiv usually designated as por,)hyroi(ls, while iu case their mother
rock can be shown to have boen quartz porphyry they are usually
caHcd schistose pori)]ivries. ]u their extreme development these
two ty].es are often i)etrographicall\- indistinguishable, and thev
in'esent an instructive instance of tlie in'oduction of identical results
by the action of the same physical forces tij.on matter of the same
average composition, thougli widelv ditlVrent in orii-.in and >tru(-
ture.'' '

It is extremely probable that numy of the rocks of this gen-
eral appearance should, in accor.hince with the above view, be
called porphyroids and as such be ineluded in the elastic division.
]t is probable, however, that an eru])tiv(. .u-igin. as true (pnirr.-i
porjthyry, is the proi)er exiilanation of the i)res(>nce of most of
them. In many cases, by the loss of the porjdiyritic individuals,
they pass into felsite schists, a section of which iu some instanceo
much resembles the ground mass or matrix of the altered porphvry.
These rocks are associated with the diorites an.I greenschists as well
as with the quartzose series; it may ])e that in the former case they
are of eruptive origin and in the latt(>r belong to the porphvi'oiil
type. A typical section from: near the .Montreal liiver shows a
fine-grained ground nuiss mostlv of quartz bu. rendered somewhat
dirtv an<l muddy bv decomposed feldspar and small flakes of
sericite. In this are fairlv large crystals of ortlioclas(>, lutich
altered but retaining their augtdar outline, together with somewhat
smaller qmirtz individuals which, in nearlv all cases, show a
rounded outline. (For localities see pages 2r), 2(i and \^?^^

Jilany of the so-called speckled i.nd mottled schists as well as
some more massive varieties are altered porphyrites. They nay, in
general, be described as gray, green and inu-plish rocks n-it\
blotches of white matter of an angular form. Tluy are not as
connnon in this region as in the TTuronian around Lake 'Minnie-
takie to the westward, but exposures ar(> found at the first falls on

' U. S. Geological Survey, Hitlletin 6i, 1890, page ll'J.

the Fredorick ITmise, River, on tlio line of portapes between
liratapinii River and Porenpine Lake, and in some few otlier locali-
ties. A section shows a fine-iirained matrix, largely oi feldspar
and secondary (piartz with hrii-ht ureen chlorite, hrown mica, etc
Implanted in this are liu'iie mnch altered plaiiioclase crystals.

Another pecnliar schist which proliahly bcdoiios here is seen
on the same line of portapes mentioned above. Tt is bhu'kish preen
in colonr, of a prononnced schistose character and exces-ively altei-
ed. A section shows plapioclase individnals snrronnded by an
exceedinply fine oronnd mass, in which the secondary minei'als,
larpely mapnetite and chlorite, arc arranped in a distinctly
spheroidal manner. (See pape 25.)

In addition to these we find a series of very fine-prained schists
of whitish or liphtly tinted pray and red colonr, readily w(>atherini;'
and presentinp a soft and pray-white snrface. They seem to contain
little or no ferro-mapnesian mineral and nnder the niici'oscopo
show fine feldspar individnals and qnartz Avhich is larpely allotrio-
morphic. This matrix is traversed liv fine dark lines, probably
re])resentinp the remains of mica ur hornblende, and is dotted by
relatively porjihyritic crystals of ])lapioclase. This rock passes iriio
coarser exami)les (still very fine however), in which the crystals of
plapioclase can jnst be made ont with th naked eye on fre.-li
surfaces. The coarser of these rocks is nndoubtedly a sheared por-
])liyrite, and as it i)asses im]K'rce]itibly into the finer variety wc
are qnite justified in assnminp the same origin for the latter. These
schists are \ery common and have been loosely described as " whirt
weatherinp schists," " >uft fine-prained schists " and i^ossibly a-i
"fine-grained ash rocks." (For localities see pages 2r» and lil.)

(r) CnisJicd i/raiiifrs (dkJ fi'lsilcs. — liocks which may with
safety be i)laced in this grou)) are exceedingly Avide-sjiread aril
present many stages of alteration. They are generally pink or light
gray in colonr with ill defined dark specks, iiiid occur intercalate!
with various schists, particularly near the head of Lake ^Litagani-
ing. Fader the microscope the only well defined mineral is quart/:,
and sometimes ortluwdaso, but the latter mineral is generally mudi
altered and presents a muddv appearanc(>. The quartz unifonnlv
shows undulatorv extinction and fre(iuentlv occurs in narrow band-
of a sonunvhat coarser texture traversinii' the ground ma^s of tli(>
rock. The mica or hornblende, as the case mav be, is alwavs mudi

rtac'os botwoon
o\v other loenli-
(>l_v (if feld-^ipui-
:()\vn mica, etc.

crystals.
<>'s liei'i' is seen
1 lilai'lvisli a,T(H'u
xccs-ively altei-
roumlcd by an
idary minerals,

in a distinctly

0-e.rained schists
dily weathering
seem to contain
the mici'oscopu
hivaelv alhitrio-
lines, probably
nd is dotted by
rock passes into
1 the crystals of
'd eye on fre.-li
Y a sheared pnr-
iner variety \vc
le latter. These
'ribed as " white
and ]"»ossibly as
25 and 31.)'
diich may with
\vide-si)read ainl
lly pink or liii'ht
'cur intercalate]
Lake ^[atagain-
lineral is qnart>:.
aenerally mui'li
nartz nnifonnly
in narrow band-
md ma-s of tli(>
, is alwavs mncli

chan^'ed and drawn ont into indefinite patches in one direction so
that it appears as oldontr or oval spots with the lonji' diajjonals
parallel. In these spots the microscope reveals actinolite threads,
ehlni'ite, majiiietite, hematite, pyrite, etc. (For localities see pages
20, 27, .'i2 and .".3.)

{(I) lloniliU'iidc ciul hiodte viica scltists, — The first of the-c
rucks is a dark pray rir sireen nKittled or honiogeneons rock accord-
ing to the dimensions of the constituents. It is com])Osed of horn-
blende and (piartz and frecpicntly shows little or no schistose strnc-
tnre. Hiotite mica schist is somewhat lighter in colonr, with sliades
of brown, never c,Teen, its schistositv is more prononneed, and it is
mnch mon^ snljject to weatherinp;. I'oth rocks are more associated
with the Laurentian than with the Ilnronian, and by the addition
of feldspar freqnently pass into g-nciss. ^lore or less aniindar
fi'aiinients r)f these rocks arc often seen indx'ilded in the trnoiss,
and they probablv at one time played an important role.

In this connection Ch. Lory, in " Les Schists Cristallins des
Alpes Occidentales," says — "Les micas schistes s(> cluu'gent de folds
jtath et passent a des jzneiss, avec lesqnels ils alternent ....
I)n reste. la separation entre les denx parties de la scrie des schistes
cristallins est loin d'etre absolue: de vrais micas schistes, avec des
conches de calcaires cijiolins, et meme de vrais gneiss, se rencontrent
jnstjiie dans le gronpe snperienr; ils alternent sonvent, li diverses
leprises, avec les schistes chloritenx on amphiboliqnes ....
Ainsi dans la serie des pierres vertes, connne dans cello des vrais
nucas schistes et gneiss, les diverses strnctnres schistense, gneiss-
icpie on granitoidc alternent entre elles, en concordance, sans qn'il y
ait lieu de snpposer que le passage de Tune a 1" autre soit lie a
rintervention de roches eniptivcs." *

It will be observed that it is considered better to include here
only typical examples of these rocks, and that many of the dark
gray and green schists, containing, no doubt, hornblende and
(luartz, are classified under the quartzose schists. There are two
reasons for this; first, because the amount of hornblende or mica
is so small compared' with the quartz and is generally so altered
and indistinct that the megascopic appearance does not suggest a
liorn blende schist; second, because the associations of these rocks

' Congres Geologiqne International, Les Schistes Cristallins. Londres, 1888
page 21.

point more to a clastic than to an ipnoons origin. It cannot bo
Jenicd however that a sharp line is ditiieult to draw, and that the
two classes pass one into the other.

II. Schists of FuAr.MEXTAi. Origin.
((/) Pi/roclaslic sclih(.<i and ash ror/rs.— The^e tcnn> are
practically svnonynions, altliongli a distinction is oencrally drawn,
the fornier' tcriu being applied to examples showing round or
angular fragments imbedded in a matrix, and the latter to fine-
grained gray rocks.

The first type is but sparingly develoiied in this region, the
best examples being seen' at the head of the south arm of Lake
:^ratagami. As here seen the rock is green in colour and very fine-
grained; it presents a distinct How structure around the included
fragments, which vary from a foot in diameter to very small dimen-
sions, and consist for the most part of light gray granite. The rock
is therefore a conglomerate and perhaps graywacke conglomerate.
Mr. Burwash reports conglomerate near Little ITawk Lake.^

The term "fine-grained ash rock" has been excessively em-
ployed to designate strata of a doubtful nature, but in many cases
the expression is used without sufficient consideration. "When
the rock can be conclusively proved to have arisen from fine vol-
canic ejectamenta the term is as good as any other, but proof is not
always available. This is possibly the origin of some of the rocks of
our region, but it is preferable to class as quartzose schists and to
ascribe to a doubtful or variable origin rocks which, by sonn'
obserA-ers, midit be considered as ash derivatives. (See pages 21 an.l
22.)

(7;) QuarfzUcs.— In order to distinguish these rocks from
those which have been called quartzose schists we must restrict tli.^
tenn to rocks in which no ferro-magncsian or micaceous ingredient
occurs, and in Avhicli feldspar plays but a small part. The colour
varies from white to lic'ht aToen or pink. By deepcniuir of colon r
owing to increase in accessory minerals the rock passes into quartzo^'
schist. Two varieties occur: — (1) Compact: a bard rock, almost
pure silica in grains and broken crystals; (2) Saccharine: a loose
friable variety resembling loaf sugar. tyi")ically pure white, bur
passing into brown and black exami)les by the occuiTcnce of hema-
tite and magnetite which are frequentlv seen in beautiful littb'
crystals. (See pages 24, 25, 20, 28 and 31.)

iReiiort of tlie Bureau of Mines, Ontario, 18'J6, page 17S.

.•fj^:

t cannot be
ind that the

so tcrni> are
rally drawn,
is: round or
ttcr to fiue-

; roc;ion, tlio
irni of Lake
lid very fine-
tlie included
small dimen-
0. The rock
onji'lomerate.
Lake/

?e?sively em-
1 many case^^
ion. When
rom fine vol-
t proof is not
f the rocks o{
;chists and to
ich, by sonii'
; pages 21 aii'l

rocks from
st restrict th>^
)US ingredient
The colonv
liuii" of cnlnnr
into quartzoM'
rock, almosr
irine: a loofo
•o white, hnr
ence of hema-
cautiful littli'

(r) Clmi slalos and micaceous clay slates occur hut sparingly
and will !)(> noted later; thev are, in some cases, clifficult to dis-
tinguish from true schists. (See page 20.)

IIT. Schists ok Doubtful or Yariarle Origin.

(n) Qiuirizose schists. — This group includes a great number
of rocks of varied appearance, with gradations of colour from al-
most white 1m dark <iTeen and urav. They are uniformly fine-
grained and consist largely of quartz, with occasionally some fine
fehlspar, and a small amount of rolouring matter, in many cases
difficult or impossible to identifv as a distinct mineral. Often, how-
ever, this matter can bo resolved into mineral species, such as pearly
white mica, asbestiform lioriiblcnde, hematite, magnetite and
varions ferro-magnesian minerals, ;^^anv of these schists show a
pronounced rhoniboidal cleavage and freqnently films of secondary
cpiartz occur on the planes of parting.

lender this head rocks are included which have been vai'iously
described as ' (|iiartzites.' Njuartz schists,' 'mica and hornblende
schists ' and possil)ly tlu; whole series loosely designated as ' fine-
grained ash rocks.' The intense metamoi^^hism to which rocks of
this tyi)e have been subjected renders the question of tlieir origin
very ditficult to answer. That they are altered eruiitives is \m-
likely on account of their acid nature in contrast to the basic diorites
with which they are so closelv associated. Their relati<.ii to the
altered quartz pori)hyries would nullify this conclusion, if it were
not that the latter roek is of much less freciuent occurrence. That
they are formed of volcanic ejectamenta is also nnlikely on account
of their immense range and from the fact that no volcanic centres
have yet been ascertained in the reu'ion. Again, the presence (^f so
much diorite indicates a basic condition of plutonic activity and not
an acid volcanic state with craters nece«sarilv of some elevation in
order to discharae the amount of ash required to form these schists.
However, it is well to remember that simie undoubted iiyro<dastics
occur, and to the westward of onr region ari^ even coinnion, and
also that it has been conclusively proved by Williams and others
that A'olcanic tuffs do ]iass into both diorites and acid schists. Any
single e.vample must receive the most minute examination to settle
its origin; as this is impossible over the wide area in rpiestion it must
suffice to name these rocks "nuartzose schists,'' nnd leave the ques-
tion of origin for future determination. Speaking generally the
opinion of the present Avritor is that they are intensely altered

scahuotitary elastics anal-.^ous t.) (,nartzitcs. A'^ 'nij-l.t b.- ex-
pc.-tCMl H.anv varieties occr, a few ..f Avliich ^vill l.o .l.-scnbo.!. _

A vrrv in'oum.iu'f.l variety, easy to rcco-nizo, an.l very wic e-
.proa.l, i< a har.1 vhitc ro.k, ueatberin^' <lull white, and irc.quently
showiim' blaek vein.. AVhen broken across tb(. planes_ot stn.tihca-
tion it unniediatelv sn-iicsts a very finc-iirainc.l (inart/itc. A Iresl,
.urface alon- the phme of stratification, however, prescMits small
ilak.'s of pearlv white mica. This rock seems mnch like tlie
novacnlite described bv Williams in the " ^larqnette Iron lle.uion
..oncernini.' which he says,— " I'hese are hard, compact, f,ne-grauuMl
but decidedlv schistose beds, locallv known as novacnlite^ . • •
The colour of these so-called novacnlites is sometimes red.li-h, som--
times pale p-eenish or yellowish . . . Tnder the microscope
they closelv resemble the oroniid mass of the (piartz porphyries.
Xo poriihvritic crystals, however, are ever observed, and^ th('
structure is too fine-p-ained to appear schistose in a thin section. '
(Sec V. S. Oeolopical Survev, IhiIMm (12, paii'c 151 et scq.).

Another tvpe is dark(>r in colour, reddish or jireenish, frequent-
Iv exhibitina' rapid chani-es in colour but alwavs showing a decided-
lv quartz-like appearance on fresh fracture. This variety is seen t,,
perfection at the third portage on the route between :Nrataganii
River and Kamiskotaia Lake. Examples from this region give from
(50 to TS per cent, of silica.

The third type is dark gray in colour, sometimes containing ^v>
more than 05 per cent, of silica, and is more readily weathereil:
it very frequently contains pvrite and it is the variety in whicli
hornblende, mica and other ferro-magnesian constituents may b.'
identified. This rock is more closely related to the diorites, whicli
it somewhat resembles in rowj^i megascopic characters, although
its constitution is entirely different.

(h) Seririte and clihr'dp sr/( /,s/.s.— The sericite schi-ts may bo
distinguished from any of the preceding rocks by a greater tendencv
to cleave; in fact thev may be described as extremelv fissile. Fresh
fractured surfaces have a silvery appearance and sometimes aiv'
greasy to the touch. Thev are much more subject to sub-acrinl
decay; a talus of broken fragments almost always occurs at the
foot of a cliff of this rock. It weathers rapidly and the surface is
frequently rusty and spotted. Tender the microscope the schisto-o
structure is most pronounced. (See pages 22, 23, 25, 20, 28, 29, 30.
31 and 32.)

iniglit be ex
^scribod.
11(1 vi'i-y wido
lul fi'cqiiouTly
s (if stvatifioa-
zite. A frc'sli
lirc^cMits small
inch liko tin
Iron lioiiiou,"
1. fine-gTaiiu'd
•ulitc . . .
veddisb, HOtni-
\\v ink'roseopc
•tz poriibyrics.
vod, and the

thin soction."

ct scq.).
n\A\, froquont-
i'inp; a dccided-
riety is seen tn
pen Matajranii
jiion fiive from

; contair.inc; nn
ily woatherod:
riety in wbioh
tnents may bi'
diorites, wbioli
3ters, altboiisi'li

scbi^ts may bf
i-eater tendency
.' fissile. Fresh

sometimes aro
it to sub-aerial
1 occurs at tbo
1 the surface is
ie the scliisto-o

20, 28, 29, 80,

The types of rock wliidi form tlie llnri^nian in this reoion
baviiiii' been briefly described, it remains now to outline ibe di-^-
tribution and to point out some local peculiarities in the various
scliists and otlier rocks enconnt(M'e(l. There niav be said to be
six distinct Huronian areas in the basin of the "Nfoose Puver; two
of these are of considerable extent and the others smaller. Iht^
first and greatest belt stretches in a north-west direction from Lake
Alntibi to beyond the ^lisanabie Tiiver. Tt mijiht well be d(^sip;-
nated the Abitibi-^risanaliie area, but for brevity's sake will be
hereafter referred to as the first area.

The southern Iwundary of this belt crosses the heip;ht of land
near ^ruskepopima Lak(\ continues north and bending- eastward
acr(jss ]\Iinniesina()ua Lake just touches the south l)ay of Lake
]\Iatafianii. Thence it extends a little east of north and cro.ssc3
the ;Xipissing-Algonia line near the IM'.tli ])ost, to which it con-
tinues ajiproximately parallel up to about the 115th mile (Bur-
wash), Avhen it bends ofi' ^:harply to the w(>st and crosses the ^Nlata-
gami Kiver at the Wawiatan Fortage after sendiiio- out a spur
Avhich crosses Lake Keuogamissee as a narrow band. From the
p(^rtaii-e it holds north and west to bevond the Pishkanogama Iliver.
There it bends northward and crosses the Trout River in a uin-th-
west direction which it holds to beyond the ]\Iisanabie Kiver. Tlie
latter river is crossed by two belts which probably both belong to
this great area, and are so figured by Dr. Bell. The northern
boundary is not so well known. It has been determined on the
Abitibi, Frederick House, ^Matagami and ^lisanabie Uivers and is
shown on the map as a continuous line joinuig these points. In
the description of the rocks of this region they will first be noted
as they occur on the Xii)issing-Algoma boundary, and afterwards
on the various rivers and canoe-routes.

The Xipissing-Algoma boundary crosses the height of land
and enters our region at the TOth mile north of Proudfoot's line
near Little Hawk Lake. At tliis point, Mr. Burwash thus describes
the series, " Ileddish ihick-bedded rocks cross the line and occupy
the east shore of the lake .... They are succeeded on the
north In a greenish gray conglomerate, and this is in turn followed
by gray ash rocks, which in places give way to what appears to be
an amygdaloid, the light coloured amygdules of which weather out

at tlio .snrfiioo." ' Ash rook? appear hi follow tlipsp outprop*? to tlio
nortli, iiiifl iit the ^'-Wd iiiilr a small area of roddish cnislu'd liTanito
is met which Is succctMlcd bv a liivonish coimlniufnitL'. At the; S4th
Jiiilc IJurwash ivports a " si'ricitc dnliiiiiitc schist," and at the S5th
" sehistost' rocks stained with iron." At the >t>th unlc dccnrs a
■weathered diabase \vith cubes (if in'rite-. while to the eastward h"
eneniintered the reddish tiiick-l)eildi'd rocks met with on Little
IJawk Lake. Followini:' these nccur wt'athered diabase, jLiray ash
rocks and chlorite schi-t with i)yrire. At the l»7th mile the line
enters a i;ranite area ami cdiitimies in it to the 104th mile. This
is. no dniilit, the corner i>f the Laurentian area which exteiuU a mile
and a halt' east of the lino. Cirayish sandstone occurs at the con-
tact, and exposures of dioritic schist, reddish slaty r<>ck and chloritic
.schists continue to the 111th mile, where the line aiiain enter-; the
Laurentian, finally leaving it at the llHth nnle, and enterim:'
grayish slaty rocks. The rock from here northward is much
obscured by the drift, and it is advisable to continue our secti(jn
northward by f(»lli)wine- the water-course of Xiuht Hawk and
Fredericdc House Lakes and Frederick House Kiver. Exposures on
the south bay of Xiirht Hawk Lake, and on Starvation C'r^ek.
which enters it, are not numerous and consist larti'ely of altered
diorites or lirccnschists. After the main body of the lake is enter-
ed the following' series is found on the west shore: — Massive green
diurite, altered dioritic schists and quartzosc schists with pyrite,
crushed granite (on an island oft' the mouth of the liedstone liiver ).
coarse hornblende and mica diorites (one and a half miles nortli of
Eedstono), fine-grained hornblende schist and a rather hard sericite
schist (X. 30° E.j. Xorth of Porcupine Eiver is- a tiue-graint'd
massive diorite and typical chlorotoid schist.

X'o exposures occur on the river connecting Xight ILiwk and
Frederick House Lakes, nor arc any seen on the latter lake except
towards the north and on the easterlv side, where is presented a
series of dark gray schists with streaks of pyrite exhibiting a bandi'd
spheroidal weathering and showing nuclei of a jasper-like variety
surrounded by the darker schist. I'his rock has a decidedly volcani •
appearance and is followed by a fine-grained porphyrite strikin;:;
S. E. and dipping 30° from the vertical.

' Report of the Bureau of Mines, Ontario, 189G, page 17S<.

•2'i

utorops tn tlio
nislifd liTiinitc'

At tll(! S-itll

id at the Sotli
mile occniv a
{' eastward li-
ith (.11 Little
)ase, jurav a^li

mile the line
h mile. This
L'XtemU a mil-'
IS at the ei)ii-
c and chhiritie
aiii enters the

and enteriiiti'
vartl is nnieh
le our seeti(jn
it Hawk and

Exposures on
■vat ion C'lvck.
elv of altered
' lake is entei-
Massive ureca
■ with pyrit( ,
dstone liiver),
miles north of
r hard sericito
a tine-grained

fht Hawk ami
er hike except
is presented a
iting a banded
crdike variety
dedly volcani •
lyrite striking

At the first falls, one and a lialf miles holow the lake, oceurs
a ridge of mneh altered jxiridiyrite weathering (Hit in white spots.
At the foot of the fall is a line-grained gray qnartzose scdiist aoconi-
panie(l hv alteretl dioritie mcks, showing under the iiiicrDseoiie
feld>liar ery<tals siirrouiuh'd hv radially arranged ehlnrite. Four
miles helow the falls, at the " Thn-t I'drtages," a considerable mass
of scriientine tilled with mai:iietite i-; seen, 'i'his is tVdlowed by
dioritie ro(d<s resembling those at the falls, and a white-weathered
fine-grained sehist. Dark hornblende diorite is the only ruck seen
from this point to the Laurentian eontact a few miles below. The
contact a]ipears to strike X. (10 " W.

Somewhat to the east of this section another is afforded by
the iJhudv Iviver and Abitibi Kiver. A gliinee at the map will
show the Tlhudx Iliver entering the Abiiilii at the great beml.
About 20 miles south of this point, the former stream become^
small and rapid, and we find exposures of pyroclastics -with three
inch inclusions, also dark schists with diorite and splaslies of quarts:
assocint ^ with a little sericite. Tust below, the river drops 15 feet
over no- ed schists with a considerable amount of quartz, alter-
nating with bells of diorite. Six miles below this point occurs a
boss of pvenite or possibly hornblende granite on the east side cf
the river: it rises to an elevation of 30 feet and is flankdl at both
sides by groenschists and some quartzosG schists. On the opposite
side of the river is an outcroj, of a dark rock with round white
spots of one-quarter of an inch diameter, exhibiting tluidal struc-
ture in the magma. Tt is proliablv an amygdaloid, Imt the speci-
men brought is too much altered for exact determination. Here
also occurs a rock -winch is proliablv a much altered porphyry.

Below this exposure we find fine gTay to black schists inter-
stratified with diorites, the whole showing rhomboidal jointing.
Just below, a snndl rapid is formed bv a ridge of pronounced diorite
schist striking X. 3.')° ^y. A mile further down a fall of 12 feet
is occasioned by a l)elt of massive diorite striking X. "W. From
here to the month of the river, a distance of 13 miles, the only
rocks seen are fine gray quartzose schist with pyrite and diorites of
close texture. From the mouth of the Black Eiver to Iroquois Falls
(5 miles) only one exposure of dark schist is seen. At the falls the
rock is a heavy dark gray weathered diabase. Xo Huroniaii ex-
posures occur below this waterfall.

To tliG eastward of the month of the Black Tlivcr, at the " Two
Portages '' a simihir dark weathered diabase with pyrite is seen.
Ahhongh the Ilnronian area extends fnrther east and embraces
most of Lake Abitibi a detailed description of it cannot be given
here, the writer's ex]-jlorations having ceased at the " Two Por-
tages."

An excellent east and west section of the conntry between
the Abitibi and ^lataganii regions is aftorded by a canoe vonte
passing from the month of the Black River westward to I'rederirk
Ilonse Lake and from Xight Tlawk Lake by Porcnpine Kiver and
a chain of portages to the Matagami. The first stretch of this
ronte, i.e., to Frederick Ilonse Lake, lies np a stream on whiolt
the only exposnres arc green qnartzose schists. From the head
of this stream several ])ortages over high sandy soil bring ns to
Frederick Ilonse Lake; bnt no exposnres arc visible, so completely
is the rock covered by sand. On the Porcnpine liiver however the
rocks are exposed at several ]ilaces.

One and a half miles \\p there oecni's a dai'k gray slate-liko
schist weathering white with bands of quartzite, strike X. 60° E.,
dip 30°. This exposnre well shows the relation previously men-
tioned of the qnartzose schists to the qnartzitcs. The next ont-
crop above this is a fine qnartzose schist with some sericite schist
becoming ferrnginons to the north. A mile higher np is a rock
representing the connecting link between qnartzitcs, as pi'cvionsly
defined, and (piartzose schist. It is almost pnre silica and very
fine-grained. One mile abu\'e this deposit is a mnch altered diabase
with asbestiform hornblende and green hornblende schist. Rocks
of similar natnre crop ont at intervals a* far ns Porcnpine Lake, a
distance of ,30 miles. From Porcnpine Lake to the month of tlie
river is only above five miles in a straight line. On the north sid(>
of Porcnpine Lake occnrs an ontcrop of a wft rock resembling
soapstone, with crystals of magnetite and veinlets of chrysotile. Un-
der the mi('rosco|)e the rock ajijiears to be nuide np of indistinct
fibres of this substance mixed with qnartz. It is evidently a mncli
altered example of the basic ernptive series. On the south side
of the lake occnrs altered diabase and gray qnartzose schist Avith
asbestifonn partings and veinlets of quartz. On the creek entering;
from the south-west were found gray to white fine porphyrite schists,
weathering quite white with streaks of quartz and pyrite. On the

r, at the " Two
pyrite is seen,
and omhract'S
nnot be given
le " Two Por-

imtrv between
a eauoe voute
d to Frederick
)ine River and
itvetch of thi--
3a ni on wbicli
rom the bead
il brino- ixs t<i
so completely
>r however tlu'

cjray slatedikc
ike X. 60° E.,
•evionsly meii-
Tbe next out-

sericite scbist
■ up is a rock

as previou>ly
iliea and very
altered diaba>o
scbist. Rocks
'ni^ine Lake, a
nioutb of tlic
the north ?itlt>
ck resenddini;-
irvsotile. Un-
) of indistinct
lently a much
he sonth side
se schist "witli
srcek enterinc
diyrite schists,
mte. On the

passace overland sonthward fronr this lake an interestirpc series of
Tocks is encountered as follows:— Soft mottled sericite schists yer>-
ninch altered, nnder the microscope showing; irregidar and strained
qnartz individuals, some feldspar in-esnmably orthoclaso, light in-
distinct sericite and considerable calcite; soft schists weatheHng
^virh ferrnainous stains, associated with bands of qnartzite; mter-
landnatiMl bands c'l qnartz and qnartzite. striking east and west, and
go filled in places with hematite scales and crystals of magnetite as
to become quite blacK.

At one and a half miles from the lake were ^een diorite schists
followed bv soft and hard exami)h'S of the sericltic scries.

Another exploration line i^assina S. E. fronr about the middle
of the south shore shows the fo'.lowing:— Ridge of granite, east and
west, flanked by soft calcareous sericite schist; hard grav quartzoso
schists; sericite schi>t; streaked quartz rock with pyrite (10 chains);
sericite schist; 20 chains of granite; soft docomposul schists
weathering out in brown spots.

On the first portage westward t'r(im r()rcui)ine Lake occur gray
qnartzose schists and greenschists.

On the second portage are seen «oft, rusty s|)otted schists with
sericite showi!tg on the cleavage ]danes. A fresh fracture across
the planes shows very fine quartz. This is followed by diorite
which is in turn succeeded by hard qnartzose schists, and at the
eastern end a rock very ^^iiuilar to that at the west, all striking about
]^. 75° E. and dipping vertically.

AitvY cr.pssing a small lake and a short portage, togeth(r about
a mile, the route ent(>rs a lake about a mile and a half h>ng in a
north-easterlv direction. On t\\o east side of this lake ar(> seen
massive green diorite and diorite schist (pvritous). and on the
westerlv side line urav quartz(.se schists l)o>siblv alterc<l porphyries,
strikin- X. E. and S. W. Two portages, the first of 15 chains an<l
the second of two miles, are required to reach the :Matagami. On
neither of these is any rock exposed.

.V third north and south section of this area is afforded by
the :Nratagami River and its approaches from the south. The
ITuronian I'* first encountered on tlu^ east sh<ire of T^ruskcgogama
Lake, and is represented by diorite and dioritic schists much con-
torted and mixed with ffueiss and bands of (piartz. Gneiss again
crops o\it on the way down the lake, but a massive green diorite is

characteristic at the first portairo. At the next portage there is n
mass of granite crossed by dykes of fine dark diabase. On the riwr
below the portage various Imrd schists and behs of diorite are seen,
On entering Minniesinaqua Lake by tlie poi-tage connecting it with
the river wo first encounter a massive diorite which gives place
westward to diorite scliists, passing into a much mixed series ui
various quartzose schists, altered porphyries and possibly porphv-
rites, crushed granites and felsites, forming an extremely com-
plicated mass and extending as far as the bend in the lake, i.e., for
about 15 miles. Here the formation swings eastward, and i.
cncountei-ed at the south end of Lake ^Matagami. On the east side
of the bay at the extremity of the lake are seen high bluffs of a
light gr(>onisli ro;'k showing the stinicture of a crushed pnrjdiyriti'
under the microscope. This is followed by greenish Iluroniaii
scliists with one inch to two foot inclusions of gray granite,
evidently conglomerate. Somewliat farther north on the west side,
sheared granite and some bands of diorite form high precipitous
shores. About a mile farther north on the east side, gray and greei;
spotted micaceous and sericitic schists mixed with bands of granite
and felsite are seen. These strike W. 10° S. and followed by
mica and hornblende schists passing into gneiss. Dr. IjcII describes
the rock on the east side of the southern lagoon as " greenish gray
quartzite, holding transparent grains." ^

A ]iortage from near Fort i\Iatagami extends eastward to Lako
Shattagami where the Iluronian is again encountered and is thus
described by Dr. Dell:—" On the west side of the narrow cove which
forms both its inlet and its outlet, beds of greenish gray clay slate .n'
shale, which are full of pyrite, are found, standing vertically, ami
striking S. 70° AV. About a mile up the south-west side, a soft green-
ish gray rock occurs, which has a dioritic appearance, but is evidentlv
of a magnesian character. It is rudely stratified, and beds, whic'h
are on edge, run cast and west."

Following the Grassy Jiiver eastward we finally aiTive at
Little ILiwk Lake. The rofks on the route, according to Dr. Bell.
are '' gi-ayish quartzite (sometimes of a conglomerate nature) and
gTeenish diorite." On Little ILawk Lake lie describes a cliff of 200
feet of "grayish red fine-grained quartzite in thick beds, int<n--
stj;at[fied with others of greenish ^elsitic quartzite holding rod
* Geol. Survey of Canada, Report, 1875-76, page 307.

rtagc there is n
?. On the rivtr
iliorite are seen,
meeting it with
ich gives place
nixed series i>i
ossibly porphy-
'xtremely coin-
le hike, i.e., iw
istward, anil is
)n the east side
ifi'h bhiffs of a
;hed pnridivrilc
■nish Ilnroniaii
gray iiranitc.
1 the west side,
igh precipitoii'*
gray and greci:
inds of granite
followed ];}■
. ijell descrlbts
" greenish gray

stward to Lake
ed and is thtis
•ow cove which
ay clay slate ^r
vertically, and
le, a soft greeii-
nit is evidently
id beds, Avhich

lally aiTive at
ig to Dr. Bell.
:e nature) aiul
3 u oliflF of 201)
k beds, intiT-
o holdinjj red

grains.'' Tliis is doubtless the thick-bedded red rock of Eurwash
already mentioned in this paper. '* On the north side of Little Hawk
Lake greenish gray clay slate is seen at two points. At tlic outlet
tliere is a massive light-green felsitic vijlcanic ash, marked with specks
of liiihter and darker colours than thu matrix."

J'"roia this exposure it is about forty miles northward through
Mataganii and Kenogainissee Lakes until the Iluronian is again
encountered. Here it consists of a narrow spur projecting west-
ward from the main mass to the east. Tiic rocks exposed show
the following series from south to north: — Fine-grained diorites;
hard gray granite and felsites; mica and hornblende schists; crushed
granite; soft Iluronian micaceous scliists, striking E. 10 X., and
dipping oO" to X. \V.; dark crystalline diorite with white blebs.
The latter rock might be described as a porphyritic diorite.

Some distance north of this series a belt of diorite crosses the
lake near ^looi'e's house.

The main bodv of the Ifuronian is encountered just north of
AVawiatan Portage at the foot of Kenogainissee Lake. It is repre-
sented lirst by a bidt of granite X. i>0° AV., followed by coarse green
diorite and soft close-bedded whitc-weatlicring schist almost ver-
tical and striking north-west. A niicrosco])ic examination of this
rock shows a very fine-gi'ained ground mass of quartz and feldspar
with porphyritic crvstals apparently of ])lagioclase, which would
make the rock a poii)livrite schist.

Below the rapids frw exposures are seen until we reach
Onicemec or Pigeon Rapids. On this stretch, however, quartzose
schists and some clay slate striking X. 7.")' W. occur.

At the Pigeon Kapids greenish crystalline diorite i- mixed
with dark gray quartzose schists and contains bands of (piartz carry-
ing gold. Considerable intermixed calcite occurs here.

Only a few exposures of siliceous schists are seen until the
first of the Sandy Portages is reached (Ivish-ki-qua-mo). where is
seen a hard gray quartzose schist (gray siliceous and dark blui-h
gray clay-slate, according to Bell). Between this and the next
portage occurs a green rock with wdiite spots. A section shows tlie
white to be entirely altered feldspar and the green mostly chlorite
arranged around the feldsi)ar. It is possibly a much altereil ])i)r-
phyrite which contained a large amount of ferro-nuignesian matter.
It strikes about east and west. At the second portage the rock at

fflmi

the top is hard p-ay quartzosc gchist followed to the north by softer
schists (nacreous, chlorotoid and talcoid schists, according: to Bel! i.
Avith streaks of quartz, strike X. Mf AV. At the foot is a large dyl<e
of green diorite. The rocks at the third portage are vari-colonrc d
fine quartz schists with a considerable amount of fine decomposable
magnesian matter, striking about north-eiist and south-west. Dr.
Eell describes them as nacreous and talcoid schists, but it is doubt-
ful if any talc occurs in them; they contain streaks of quartz ami
much pyrite. Four or five miles below these iwrtages the
Kamiskotaia Sagaigan River enters from the west. On ascendhia-
this stream slatv diorites are first encountered and then haul
quartzose schists. At the third poi-tage on the rout to the lake
a sjdendid development of the quartzose schists is seen. Tho
country here is bare and rises into hills of considerable size which
give a linmmocked aspect to the whole region. The schists are 'if
many colours, white, gi'een, gray, purple, etc., and strike a little
south of east with a nearly vertical di]). A section siiows a pro-
nounced schistose structure with fine quartz exhibiting undula-
tory extinction and souietimes an-anged in lenticular i)atclu'-;.
The other ingredient is of variable nature, brown mica being very
common as well as chlorite and perhaps also sericite. These schists
average TO per cent, of silica. On the stream flowing out of Ivamiv
kotaia is seen a fine-grained grav diorite followed by a coarsrr
variety and on the lake itself is a typical quartz diorite of dark gniy
coloiir.

For a description of the river !Matagami below the Ivami~-
kotaia Dr. Jiell's report is relied upon,^ as the Avriter's investiga-
tions did not extend farther north.

Tlie following is a brief summary of the rocks recorded: — Oa
the east side, 30 chains lielow the branch is an exposure of ''massivi',
gray, semi-ciwstalline steatitic rock, holding grains of specular iron,
and cut by small veins of whitish bitter spar." This is followed fur
eleven miles by outcro]")s of greenish gray diorites, both massiA(>
and slaty. Then occur dykes of green crystalline diorite. Half a
mile further is dark gray (piartzite with iron pyrites and clear
qiiartz grains, X. 80° AV. At the end of another half-mile a
massive, light greenish gray siliceous schist resembling diorite rnn^

1 Geol. Survey of Canada, Report, 1875-76, page 312 et teq.

i^.-s

north by softor
rdiiip: to Bel! I.

is a large dvke
V vari-coloiiV( J
J dccoinposabk'
lutli-wcst. Dr.
but it is (ioxibt-

of quartz and
> portagO!= till'

On ascendiiii;-
[ind then lianl
it to the lake

is seen. The
ible size Avhieli
3 schists niv 'if

strike a little
X siiows a pro-
biting nndnla-
icnlar ])atelu'~.
iea boino- verv
Those schists
; out of Kamii-

by a coarser
tc of dark gray

iw the Tvanii--
ter's invostig;!-

recorded: — Oa
re of ''massivf,
: specular iron,
is followed f^r
both massive
iorite. Half a
ites and clear
pr half-mile ,i
ig diorite run-;

K. 75° W. (quartzose schist). At Sturgeon Portage, three and a
half miles farther down we find hard greenish gray slaty diorire,
K. 35° to 00" \V., cut by a great dyke of greenish gray slati-like
crvsralline difjrite rnnning north and south. Six miles below the
portage are seen ''soft grayish green calcareous talcoid schists, ^.
55' AV.'' Eight miles more bring us to outcrops of "gray diorite
or volcanic ash, holding sliarn crystals <jf black hornblende, larger
grains of white feldsitar, and small crystals of iron pyrites." At
Loon Portage, three miles down, the rock is " dark, greenish gray
hornhlendic schist," and at Davis' lia|)id. a mile below, it consists
of " chloritic and hornblendic schist." After this last portage wo
pass into the Laurentian gneiss.

On the Ground Hon' River the southern boundary of this great
area is considerably fartlier north than shown on Dr. Pell's map.
This ri\-er was examined for ten miles below the point there re]uv-
sented and the contact was not found: the whole region around
AVawayeskatching Lake and a considerable distance to the east is
gneiss. The same observation liolds true on the Pishkaungama
Eiver, the Iluronian at the contact being represented by massive
and schistose dioriles.

This area is acain met with on the }\[isanabie Piver. which it
crosses in two belts separated by about eight miles ot gneiss, The
more northern of these belts i- seven or eight miks wide, at right
angles to the general strike, and the southern not more than six, at
the point where the river crosses it. The rocks in both belts do not
differ materiallv from those seen in other parts of the area. In the
first belt the average strike is a little south of west. tl\c rocks being
the usual assendilaue of ciuartzose schists and some mica
schists crossed by belts of diorite. The second belt, towards the south,
shows much quartzose schist and fine hornblende schist. '1 here was
no opportunity to examine these rocks west of the river; the Inints
as shown on "the sketch arc copied directly from Dr. Bell's map.

The second Iluronian belt extends in a north-ea>terlv direction
for abont eighty miles, crossing the Canadian Pacific Railway be-
tAveen Pidout and AVoman Piver, and terminating near A<pies(pia
Lake. The area end)races Sa-ge-tow-wash-ka, :Ma(:agaming and
Gromid ITog Lakes, and it was along this route that it was exam-
ined. On passing down the river from Rice Lake gneiss is en-
countered as far as the third portage, a distance of about three and

a half miles. Here, however, UTay hornblende schists crop oiit,
followed by uranite Avith inclnsions of dark hornblende schist
in such numbers as to indicate a sort of pant breccia. From
this point to Lake Sa-c;e-tow-'\vash-ka extends about a mile
and a hal+' of swamp showins; only occasional exposiires 1 gray
granite and green diorite.

-Vt *ho prominent point one and a half miles from the mouth
of the river ou the east side is a massive green diorite, Xorrh
from here, on the west side of the lake, a ty]ncal hornblende
granite extends for some miles along the shore. On the bay from
which the ri\cY flows out are first seen very fine-grained whito
schists, almost pure (luartz but probably containing some tine
sericite, for they weather out a dull white. These rocks mucli
resemble the variety des(!ribed as novaculite. They are followed
by green chlorite schists, mixed with greenish hornblende granite,
to the foot of tlie bay. Between this lake and Lake ^fatagamiiig
there is a fall of 150 feet; the country is very rough and the rocks
varied and well ex])osed.

At the first portage, immediately on leaving the bay, are seen
dark green chloritic and hornblende schists passing into light' r
mottled schists to the north. At the next iiortage, one and a half
miles down, green rocks like those above are seen si.)lashed with
(piartz. Another mile and a half intervenes to the third portage,
where are found a syenitic rock, greenschists with pyritc and a fine-
grained sheared granite showing under the microsc(3pe a large
percentage of fine quartz, a verv little greenisli mica and scattered,
relatively large, crystals of orthoclaso. A short distance north a
series of vari-coloured pchisis cross the srream. These rocks are
somewhat soft and sericitic in places and contain small seams
of quartz. Very similar rocks, striking east and west, are
seen on entering ;^[atagaming Lake; they rise into considerable
hills, having a banded appearance of white, arcen. reddish, purple,
etc. Xearly half a nule of po^diyritic hornblende granite follow-,
occurring in ])elts. interlaminated with gray quartzose schi-^t^
and light green chloritic schists, striking north-east and dipping
40° to the north-west. Whitish schists arc common about a mile
beyond the wide granite belt. At the point where the lake begins
to open out we encounter dioritic schists followed by hard grav
and light green varieties. About a mile lower down, where thi>

ists crop oiit,
iLlonde schist
rcccia. From
l)out a milo

siircs ^ gray

5111 the muutli
orito, Xorrh
al horiibloiulii
the bay from
irainod wliite
iig- i^ome tiiic
e rocks niiicli
are followed
leude granite,
; MatagaiuiiiiT
and the rocks

bay, are seen
'; into liglitiT
ne and a half
si)la<hcd witii
third portapv,
ite and a fine-
■cope a hiriio
and scattered,
tance north a
ese rocks are
I small seams
id west, ai'c
) considerabK;
ddish, purple,
I'anite follows,
rtzose schists
and dippine;

about a mile
le lake begins
by hard grav
n, where the

lake bends to the east, soft sericite schist is found, striking east
and west and dipping 20" to the north. 0])posite are seen hard
quartzose schists. Very little more rock is seen on the lake or on
the river below as far as Ground Hog Lake.

Half a milo north of Ground Jlog Lake soft friable whitish
schists run east and west, dipping at a high angle. Three miles below,
the river is broken by the Ivaskamene liapids, where are seen soft
micaceous slate-like rocks suitable for whetstones. Two miles
below these rapids sericite schists cro]) out, striking east and west.
Two and a half miles from this point a heavy rapid, ^lekesewa.-un,
occurs. Here a dyke of heavy diorite crosses the river. u few dey,rees
north of east; above it are seen gray and green schists, and below
five or six varieties of closelv baudetl quart/^ose schists. On an
island a mile and a half farther down we lind hard gTay cpiartz
bchists and diorite with pyrite. The Latu'entian contact occurs
just below, but a dyke of massive diorite X. -M)° W. is found at
the Ostandigististagan Fall a little farther down.

This area is also visible on the canoe route between Ground
Hog and Pishkanogama Jvivers. The trail leaves the former river
a few miles below Ground Hog Lake. On the third iiortage gneiss
is encountered, but towards the end of the trail it gives place to
briji'ht e-reen fissile schists, probably chlorite. On the small lake
succeeding, similar schists are observed striking east and west and
mixed with sugary quart/ite. Similar rocks are seen on the next
portage, and the northern and eastern shores of the following lake
are of gneissoid muscovite oranite, while gray micaceous ITuronian
schists occur to the south and west. A creek connects this lake with
a larger one on which are seen in order, fine grav gnei-s, pro-
tovermiculite (I) schists, striking noi-th-east and south-west, gray
quartzose schists striking east and we<t and diyiping 20° ^'., soft
friable sericitic schists striking north-east and south-west and
dipi)ing vertically, soft brown highly ferrnainous examples s]ilashed
with quartz; fresb specimens seem to indicate an extri'inely altered
porphyrite infiltered with secondary silica.

is'ear this last exposure a snuill stream enters another lake on
which are found green sericitic schists and sugary (piartz, massive
gre(>n and schistose diorites with iiyritc, soft white schists, and hard
white spotted varieties, probably altered porphyrites. Fresh speci-
mens are much greener than the surface samples, and under the

inicro«copo show fi.u-m-alncd iM.]vM- dceoinposition products and
indistinct liii-lit i-Tccn chlorite wit', a little quartz. The second por-
tnuc l.cy..nd this lake j.-in^ a stn-ani ll..\yin- into the Pishkann-
fiania; on it occur hard ,i>Tay quartzose schists.

The lluronian area crosses the rishkano-anui Uivev in thrrc
narrow helt-. The most northerly has a width <d" about throe inih'^
and shows hut few exposwes of white, uray and ,i>reen stdiisjs aver
aiiinu' north-west in strike and dii)pini:' to the south-west. Near thr
foot of ri<hkano.i>:ania Lake the second belt crosses au<l shows green
foliated schists ai)parently uiore (luartzose than dioritic. The third
belt is found as a narrow band about three miles up the lake, and
consists of foliated oreen talcose schi-^ts, striking east and west, with
a di]) of no" to the north.

Trom this descri))tlou it will bo obsorved that the basic eru])-
tivos are found towards both the north and south borders oi \\ir
area, and that tlu>y are not at all common towards thex-eutre. Thi>
is also true of tlu^ altered basic enq)tlves, diorite schist, grconschists,
etc. The (luartzose schists, cru^^hed granites and more acid rocks
generally are far ujore characteristic of this belt than of the first,
where aitere<l basic cruptives ])robably constitute a large percentage
of the area. *

The third great llunjnian area occurs on the south-west arm
of ]\lisanabie Lake, where it is exposed for about eight miles; it
narrows to a j)oint towards the north and crosses Long Lake as a
spur. On approaching this region from the east we first encountov
bands of diorite cutting the gneiss nearly north and south an:l
di])ping 20° E. Four nules west of Ferry Point wc enter a region of
mixed schists striking about north and south, lied, green and gray
quartzosc schists and crushed granites arc interlaminatod with
diorite, diorite schists and much grecnschist or altered diorite.
These rocks fonu high bare hills the sunnnits of which seem to bo
occiqiied by massive diorite while the various schists form the
flank.

The fourth Iluronian area crosses the Abitibi River, extending:
from the Lobstick Portage to below the canyon, a distance of about
seven miles. The average strike is a little north of west and tho
effect on the river is remarkable; a series of heavy rapids are form-
ed followed bv a distinct canyon two miles in Icngi:!!. This
formation is decidedlv eruptive in origin, little trace of schists of
any kind being observed.

products and j
le second por-
hc Pij^hkann-

!ivor in tlirco
it throe mill-
1 scliists aver
St. Xoar tlic
I sliowr! grci-ii
L'. Tlie thiiNl
the hike, au<l
nd west, with

le basic erni)-
orders of thr
•centre. Thl>
, oTcenschists
re aci<l rock-
1 of the fir?t,
s;e percentage

uth-west arm
i-iht miles; it
nji' Lake as a
irst encountcv
id south aiil
er a region of
:een and gray
niinated with
tered dioritr*.
ill seem to he
sts form the

'or, extendi) It:
ance of about
west and tln'
iids are fonn-
cngth. This
of schists of I

The first indication of the presence of this belt is seen on an
island above the Lobstick Portaiic. where tlie liiieiss passes into
]i:i('a s(diist strikinsr north-wot and sontli-east with a dip of 20
to the north. Dn the east side the rock i- diorite and at the south
side it is augite sveuite with soiu(> plagioclase, and with numerous
liarnets in the more weathered parts; it varies in structure from
massive to quite schistose and towards llic -outh-wesi corner
is horiddendic and hiahlv pvritous.

At the Lol)stick Portage is seen tirst a highlv horidilendic
schist followed by streaks of dark gray schist with pyrite, whicdi
is succeeiled by augite syenite and (piartz iiorjthyry. heconiing more
granitic in appearance down stream.

Augite syenite occurs about two miles tlown and is traversed
l)v narrow bands of Rue black diabase, running in all dir(>ctions and
showing beautiful examples of dislocation and niiiiiainre taultnig.
This rock seems to pass into diorile or rathir alternates with
diorites; a rock occurring above the Ibrcdi Portaiic itresents a much
altered appearance and may he a syeiute or diorite with spheiie
and mellilite. Above the Oil Can Portage a highly feldspathic
augite syenite of coarse structure is seen; at the foot of the portaije
the rock is somewhat the same hut contains ralhir more ])lagiocla<e,
ioid is grayish black and speckled in appearance^ and shows evideni'C
of ilow structure running -N. ^io \V. iSonie >uiall veins of iine crystal-
line calcite occur throughout this helt. At the head of the cany(-tn
the rock is practically the same as at the Oil Can Portage. Three
quarters of a mile down a snndl amount of an<irthosite occurs, and
a little beyond a much decaved granite. One iuil(> down tlu^ cliffs
are nearly 200 feet high and are formed of dark gabhro nnxed Avith
irregular masses of granite an<l traversed hv numerous calcite^
bands. A crushed granite or perhaps quartz porjthyry succeeds to
the north and continues, with a north and south strike, to the end
of the rough water.

How far the belt may exten<l east and west is not known. Dr.
Bell does not mention it on the :\ratagami. but describes numer.ms
eruptive dykes, which may represent it. On the .\[i?anabie, nearly
in the required line of the strike, a TTuronian belt crops (Uit which
is possibly continuous with this, but lackin--' proof of the continuity
we must regard it as a separate area. On a.scending the river it is
encountered about a mile below the point where the river makes
8

«4

the fii-ciit 1)011(1 to the eastward and i,-; reiire^eiited l)y a heavy rock
uf trappeaii a.spect; this is I'ldlowcd hy various sehists of dark
colour, intorhmiiiiatod bands of diorite and l)olts of irranito and
folsite. I'nfortunatciy want of time prevented the ohtaiiun^' of
specimens, a nneros('oi)ic examiiiation of wliieli wotdd have estab-
lished or disproved the identity cd" these rocks with those at the
canyon of the Aliiti])i. The f(»rination continues to the foot of the
honp- I'ortaiic a distance of aho\it five miles. (See Dr. Bell's
h'rporl, ])aiic '■]'']')).

X(>ar St. Peter's Portai>e some narrow hands of Tluronian
rocks intersect the iiueiss; these consist of both dioritic and quart-
/ose S(dn'st, hut it is douhtful if they are of sutHcient extent to ho
cla-ssed as a lluroiuan area.

The only other Iluronian belt is that lyinc,' to the westward
of Trout Lake as dctennimd by Dr. Dell. The writer had no
opportunity of .<eeiiiji>' this area and depends entirely on Dr. Bcdbs
observations that the rocks here consist of '* rather dark coloured
hornblendic schists, with an east and west strike."

eavy voek
> of dark
anite and
aiiun^' of
II vo estal)-
iso at the
out of the
:)r. Bell's

nur(»iiian
nd quart-
cnt to 1)0

westward

r had no

Dr. Bell's

coloux'od

SUMMARY.

As a petroaraphieal series most of the rocks of those various
rejiious may ho desorilxMl iis altered eniiitive<, hoth acid and basic,
which have, for the most |)art, lieen suhjected to iuteii-e nietaiiim-
phisiii. Mixed with them are other schists <d' chistic, oriiiin consist-
iiiii' very largely (d' (luartz. The whole comi)lex shows evithMice of
iiiiicii dynamic metamorphism and represents a more or loss con-
stant schistose structure, with th(> himinae dipiiinii' at iusih angles.
While a great similarity exists between the ditl'ercnt areas there
are, in a general way. some peculiarities belonging to each. The
first or great area i-<, on the whole, more l)asic tlian the second, tlie
rnost important rock being diorite with its (hn'ivatives diorite schi-t
and greenschist. These basic rocks seem to form the centre of tlie
area and the more acid representative". (]uart/.(>se schists, altenHJ
porphyries, etc., appear to be distributed more towards the bordeis.

The second area Is decidodlv umre acid with a preponderance
of crushed granites, felsites, altered (piartz porphyries and acid

schists.

The third division ihow-i considerable diorite of a somewhat
massive nature, froquontly fornnnii' hills, whicdi are tlankeil by the
same series of schists as in the other regions.

The lluroniau area of the Abitibi canyon is ([uite different
from any oi those and must be roganh'd as a large eruptive dyke
coini)os(>d princi]>ally (d" augite sveiute passing into gabbro.

The schistose areas seem to be comparable to hawson's Ivee-
watiu scries, at least in part. They mav aho be couii)ared to the
gi-eonstone schist area of iMarquette. Their origin is i)robably
similar to that of the regions mentioned and will not be discussed
liere; the reader is referred to 15uUetiiis i'd (ISild) and SO (1S!)2)
of tlio V. S. Geological Survev, ami to the lieport of the (ieological
Survey of Canada^ Part '% 18S8.

The sketch map accompanving this ]y.\])vv is compiled largoly
from Dr. Bell's map of the region, corrected in ]daces by the more
recent determinations on the base and meridian lines of Alexander
Nivon, O.L.S., as well as hv the compass surveys con<lucted by the
writer of this paper ahmg most of the canoe routes. It c'annot claim
any great accuracy but will serve to indicate, in a general way. the
distribution of the rocks in question. Owing to the small scale it
was thought advisable to introduce but few names other than those
mentioned in the text.

V/7

^y^

SKETCH or
PART

or MOOSE RIVER BASIN.

Scale. — About 20 Miles = I inch.