^ ^ bl^ 4* IMAGE EVALUATION TEST TARGET (MT-3) J/ ^/ ^it. -< « LO I.I ;f:i^ IIM !r 14= 2.0 1.8 1.25 iim 11.6 Photpgraphic Sciences Corporation k ^ \ •\ 23 WEST MAIN STREET WEBSTER, NY. 14530 (716) 872-4S03 autres exemplaires originaux sont filmds en commengant par la premidre page qui compcrte une empreinte d'impression ou d'illustration et en terminant par la dernidre page qui comporte une telle empreinte. The last lecorded frame on each microfiche shall contain the symbol —^' (meaning "CON- TINUED "), or the symbol V (meaning 'END"), whichever applies. Un des symboles suivants apparaitra sur la dernidre image de cheque microfiche, selon le cas: le symbole — ► signifie "A SUIVRE", le symbole V signifie "FIN". Maps, plates, charts, etc., may be filmed at different reduction rdtios. Those too large to be entirely included in one exposure are filmed beginning in the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate the method: Les cartes, planches, tableaux, etc., peuvent dtre film6s d des taux do reduction diffdrents. Lorsque le document est trop grand pour dtre rerroduit en un seul clichd, il est filmd d partir de Tangle supdrieur gauche, de gauche d droite, et de haut en bas, en prenant le nombre d'images ndcessaire. Les diagrammes suivants illustrent la mdthode. 1 2 3 1 2 3 4 5 6 '//^ ^ LAKES OF NOETH AMEEICA A READING LESSON FOR STUDENTS OF GEOGRAPHY AND GEOLOGY BY ISRAEL C. RUSSELL TBOFESSOR OF GEOLOGY, U.NIVF.K8ITV OF MICU1GA17 GLXN & COMPANY BOSTON • XKW YORK CHICAGO • I.ONDOX SB Ciil'VliKiiiT, 1895. liV ISKAKL C. Ul'SSKLL ALL BiaUTS llliSKUVED 30.7 iCht flttitn.-tiim Drtsx (,1 \N \ 1 i)M r \ \ Y ■ I'l-'i- Ann Arbor, Michwan, April 12, IH'M. GROVE KARL GILBF.RT, V. S. OKOLOOICAL SIRVKT, WA91IIX(JT0N, D. C. My Dear Sir : — It is now fourtee,, years since you first «„i.,ed „.y f„ofsteps to the beaches of Lake »onne- vill an., po.nte. out .he striking contrasts i„ the sc.pturin, of the n.ountains above and beh.w the hor.on to wh.ch that ancient sea fiooac the now desert valleys of Utah. For several years Mnula lake. „. Nevada, California, Oregon, and Washington; and through your a.lvice and su«,es^.,.s 1 was enabled to see nuu.y .hin.s ,hat otherwise n.inht have escaped notice ™« yitin. t:.,s little book, which so inadeauately describes son.e of the n.ost interesting acknou ledge o your volume on Lake Bonneville and of your more general discussion of the lopography of Lake Shores-books that are numbered an.ong the classics of An.erican geolo-'y .edica";-::;:^:;::^""^'"^" " ^'^ ~"'^'" '"^•^"^^"-- ^ ^^« - ^^ ='""-' - I remain, very respectfully, ISRAEL C. RUSSELL. PREFATOPvY I^TOTE. A lau(;h ijortiou of the facts [)eitiiiiiiiig- to the lakes of North America, jjieseuted in this hook, were gleaned hy the writer during thirteen years' geological work for the National (iovernnient, and are lecorded principal- ly in the jnihlications of the U. S. Geological Survey. The facilities for exploration afforded hy my connect' '»n with (iovernnient surveys enahled nie to visit yarious parts of the United States, inclusive of Alaska, and to ohserve many phases in the topographical development of our continent. The puhlications of the U. S. (Jeological Survey, and of several State surveys, also contain the records of ohservations by others, relating to the subject here treated, which have been freely used. It is hoped that this popular presentation of a small part of the lesults cf the various surveys referred to Avill serve to direct attention to tlie rich and varied store of information contained in the reports of my colleagues and fellow- workers. Besides the publications of official surveys, many pajjere relating to the subject here discussed have appeared in journals, proceedings of scientific societies, etc., to which references may be found in footnotes in this volume. The origin of lake basins and the history of the great cycles in the development of the relief of the land to which they pertain, have Ijeen discussed especially by Professor W. M. Davis, of Harvard University. Professor Davis lias also read the manuscript of this Iwok and kindly given me the benefit of his criticisms and suggestions. I. C. II. INTRODUCTlOiq". Lakes have their Inrth iind ileath in the t<)pc)jTriV[)hic development of the liiiid. A certain chiss form a eharacteristie feature of hinds recently elevated above the sea; othew belong with the earlier stages (ir youtii of streams; while still others iippear during matuiity or in the old age of the rivers to which they owe their origin. I^akes of a different ty[)e are associated with modifications of topography due to glaciid and (o volcanic agencies, and to movements of elevation and depression in tlie eai'th's crust. Lakes, like mountains and rivers, have life histories which exhibit varying stages from youth through maturity to old age. The span of their existence varies as do the lives of animals and jdants. In :irid regions they are frequently born of a single shower and disappear as quickly when the skies are again briglit; their brief existence may be said to resemble the lives of the Ephemera. Again, the conditions are such that lakes perhaps hundreds of square miles in area, are formed each winter and evaporate to dryness during the succeeding summer; these may be compared with the annual plants, so regular are their periods. Still othera exist for a term of yeara and only disappear during seasons of exceptional aridity ; but the greater num])er of iidand water bodies resemble the Sequoia, and endure for centuries with but little apparent change. So long are the lives of many individuals that human history has recorded only slight changes in their outlines, but to the geologist even these are seen to be of recent origin and the day of their extinction not remote. The tracing of the life histories of lakes and the recognition of the numerous agencies that vary their lives and lead to their death, gives to this branch of physiography one of its principal charms. ^mtm vUi iNTit<)i)i(rrioN. Mi- Lakes are also expiessive of cliinatlc coiulitions. In hnniid n'^ions they usually overflow, are fresii, and vary hut HJij^'htly in ;in'a or in (It'itth, from season to season, and from i-entury lo ctMitury. In arid lands tlu-y are frequently without outlets and eonst'tjuently alkaliiu! and saline, and fluctuate in sympathy with even the nunor chant^'es in their climntie environment. The history of a lake l)e][,nns with the oricfin of its hasin and considers amon^' other suhjects the movenu'uts of its waters, the changes it pro- duees in the topo^naphy of its shores, its relations to climate, its geoloKicid functions, its connection with [dant and animal life, etc. It is in this general order that the lakes of Ncnth America are considered in the present volume. The standpoint from which the suhject is treated is that of the geologist and geographer, its relation to man being left to the archaeologist and the historian. C () N T E ]S^ T S. INri{01)L< TION. ril.VI'TKIt I. ORIGIN OF LAKE BASINS, l)i:i'iiKNsiOKs ON Ni;w L.\m> Aiii,a«* . ... JJamin-* nil: ro Atmosi-iikiiic A(ikn< ii;h , , , , " '• ■• Ai^iKors Af STocKTf)X Bar, Utah , Mai- of Gravfi, Bar retainin<; HiMDoi.irr Lake, Nevmia . Mai" of Crater Lake, ORE<;oy •■...... Sketch of Ahert Lake, Oregon- . Chart of Lairentian- La.ve*, snowisr; rREVAii.iNr, Cirrents Se.\-ci..ff in BoiLiJEK Ceav, South Maxitou Island, Lake Michigan . * . . . . . . . Sea-ci.iff IV San-iiston'E, Ar Train Island, Lake Sii-erior . E.mhankment formed in Lake Bonneville, Wellsville, Utah Gravel Spit, Shore of Ar Train Island, Lake Siperior A Kecitrved SuT, Gkaxd Traverse Bay, MiciiitiAN . . . . Sea-CLII FH AND TeRRACES FORMED ON THE SllORE OF LaKE BoNNEVILLE OyL'iRRH Range, Utah Map OF Saline and Alkaline Lakes in the Arid Region . Map OF Great Salt Lake, Utah, showing; Changes in Area . The Hi': I Sierra, from North Shore of Mono Lake, California Map of Mo.vo Lake, California Map of Lake Iroqlois Map of Lakes Bonneville and Lahovtan . . . . . , TiFA Towers on tsie Shore of Pvhamid Lake, Nevada TiFA f;KAGS, SHOWING Si CCESSIVE DEPOSITS, CaRSON DesERT, NeVADA Typical Specimen of Thinolitic Tcfa Pyramid Island, Pyramid Lake, Nevada . . , Cross Secttovs of the CaSons of Canadian and Mora Rivers, New Mexico Profile of a Sea-clifp and Terrace Profile of a Cct-and-Built Terrace . , , Sketch Map op an Emrankment Map of Sand Bar ahoit the Head of Lake Scperior Map of Sand Bar on the Soith Shore of Lake Ontario Section of a Delta Diagram showing the Rise and Fall of Lake Laiiontan Diagram showing the Relation of the Terraces of Lake Lahontan TO Pyramid Lake Page • 8 . 10 12 . 14 20 , 20 ;!4 42 , 44 40 , 48 50 52 70 78 84 8h 08 10!! 110 112 no 120 18 44 47 48 49 60 108 111 LAKES OF NORTH AMERICA. CHAPTER I. ORIGIN OP LAKE BASINS. Difficulties arise in cla.ssifyino- lake basins, similar in character to those met with when a systematic discussion of cfhiciers, rivers, mountains and other features of the earth's surface is attempted. That is, there are no natural fi^ron[)s se[)arated by hard and fast linos, into which they naturally fall. Certain types may be selected, however, answerint,'' to genera among })lauts and animals, about which most lakes may he g;oui)ed. In selecting these types we are guided by their mode of origin, and are thus led to an incomi)lete genetic classification, based on the natural agencies which produce depressions in the earth's surface. I'oin-c'H.sions on now land area. — On lands recently elevated above the sea or left exposed by the eva[)oration or drainage of inland water bodies, there are usually inequalities, and \vater frecpiently collects in the dei)res- sions and forms lakes. There are com})aratively few lakes of this type in North America, for the reason that large portions of our coasts are sinking and new land areas are rare. The lakes of Florida, however, are good e.vam[)les of this class. They are surrounded by marine rocks of recent (-rigin. and are but slightly elevated above tlie sea. In fact, all of the topograi)hic features of Florida indicate inunaturity. The luxuriant, vegetation of the southeastern coastal [)lain, masks the slight inecpialities of the surface, and, by clogging the slack drainage, leads to a greater 1 Tliis subject has hccii discussed liy numerous writers, and ]ias led to controve.sies not yet ended. Tlie must extended and most sy.stemati;' treatment tiiat it l.is received may lie found in an essay by W. .M. Davis "On the classification of lake basins," in Hoston Soc. Xat. Hist., rroc. >ol. til. 1HS2. ji]). :! 1 ">- .'iS I . The numerous references iriven in this paper constitute the best biblio<;rai)liy of the subject available. An imiiorlant .supplementary pa[)er by the same author is republished as an ap|ieudi.\ of thi' present volume. LAKES OF NOUTH A.MKltlCA. I'l' ' !li' expansion of the lakes than would appear if tlie land was barren. The Avealth cf vegetation tends also to })reserve the orioiaul harriers fioni erosion. Al)oiit the southern shore of Hudson hay lliere is another area reeently ahandoned hy tlie sea, on Avhieh there are hdces, hut this region is so little known that it eannot he jjointed to with contideiiee as a ease in point. • In the Great Hasin, as tlie vast area of interior drainage l)etween the Sierra Nevada and ]{oeky mountains is termed, there are many lakes, some of them of large size, wliich oeeui)y depressions in tlie surfaces of sedimentary deposits left exposed hy the evaporation of much larger Pleistocene water bodies. Great Salt lake and Sevier lake, Utah, occupy the lowest depressions in valleys formerly flooded by the Avaters of a great inland sea to which the name Lake Bonneville has been ai>plit'd. Pyramid. Walker and other Ldces in Nevada, occur in valleys Avhich are deeply filled with the sediment of another ancient water body named Lake Lahontan. In these instances, however, and in many others of similar character throughout the Arid Region, the positioiis of the present lakes on the apiiroximately level floors of desert vallej's have been partially determined by I'ecent movements of large blocks of the earth's crust adjacent to lines of fracture, and by the unecjual deposition of alluvial material swept out from mountain valleys and dei)osited on the adjacent plain. These recent changes have modified the character of the basins now occui)ied l>y lakes, but essentially they are depressions on new land areas, and form the most typical examples of their class that can ])c found in this country. There are irw land areas about the borders of the Laurentian lakes, which have been left exposed by the recession of still greater lakes that occupied the same basin at a com[)aratively recent date, and also in the region drained by Red river in Minnesota and Canada, formerly flooded a vast lake named in honor of F^ouis Agassiz. Along some of our rivers, also, which flow through ancient valleys now deci)ly filled, there are narrow aieas of new land, similar to the recently ex[)osed borders of the Laurentian lakes. In all of these instances, however, the lakes foimcd in the ine(]ualities of the surface are small and of little importance. Lakes on new land areas are surroundeVV1\ 1 OUliilN Ol' LAIvK HASINS. 8 ere are , ill the if much !, Utah, I Avaters as heeu valleys er l)0(ly y others , of the sys have i of the ^position (I on the r of the ; on iie'.v that can in lakes, kes that ) in the )()(loh)rado, have recently been described by G. K. (iilbert. .Tour, of Geol., vol. il, 1805, pp. 47-4». LAKKS (»F NORTH AMEUICA. ilii: ! ill r 1 1 I' I ! I I ! I action, are wind erosion basins or areas of [)ronounee(l rock deeay, from which ghiciers have removed the h)osene(l material without deeply abraid- ing the uuweathered rock beneath. The mode of origin of rock-basins is still a matter of controversy, but it seems evident to the writer, not only from I'eading the viirious views advanced by others, Init also from personal observation in many lake regions, that rock basins have been forined by each of the agencies mentioned as well as by a combination of the two. The formation of basins ])y ice erosion and by chemical solution might be included among the results of atmospheric action, but luider the classification here adopted they fall in different categories. Atmospheric agencies also lead to the formation of basins by depo- sition ; as for example, when sand is drifted into dunes. Drifting sand freciuently travels across the country for scores of miles in the direction of the prevailing winds, and sometimes obstructs valleys so as to cause lakes to form. The best illustration of this occurrence known to tlie writer, is in the central part of the State of Washington. The drainage of one of the deep narrow valleys known locally as " Coulees," which trench the Great Plain of the C'oluml ia, has been obstructed by immense sand dunes, so as to form a dam and retain the water of Moses lake.^ Below the dam of drifted sand there are several springs fed by lake waters percolating through the obstruciion. These serve to keep the v/atersof the lake fresh. 'I'he s])rings below the sand drifts unite to form Alkali creek, which in winter sometimes has sufTicient volume to reach the Columbia, but in summer suffers from evaporation, and terminates in a series of alkaline pools. Drifting sand may lead to the destruction of a lake as is illustrated by an exami)le in western Nevada. The branch of Truckee river, supplying Winnemucca lake, is partially obstructed by wind-blown sand, and a struggle for supremacy between the river and the encroaching dunes is in progress. Should the sands prevail and a dam be formed, the water sui)ply of Winnemucca lake woidd be diverted to Pyramid lake, and its basin would soon become desiccated. Volcanic dust is carried great distances by air currents, and might accunudate in a valley s(» as to obstruct its drainage. No lakes, retained by dams of this nature, are known on this continent, although thousands (»f square miles in the western part of the United States were covered, in Pleistocene and recent times, to a de})th of many feet Avith fine volcanic 1 I. C. Kussell, "Geological Jieconnoissance in Central Washington," U. S. Geol. Siirv. Bulletin, No. 108. OIJIGIN OF LAKIO ItASINS. iiy, il'om f iilmiid- 'k-l)iisiiis iter, not [so from ive been lution of solution lit under by de[)o- iuj;' sand direction to cause n to tlie drain cige ;," wliich immense ses lake.^ by lake keep the ;e to form to reach erminates llusti'ated cee river, )wn sand, croachin']^ e formed. Pyramid nd mio-ht , retained thousands overed, in e volcanic Geol. Surv. dei)osit.s, which in some instances have assisted other agencies in pro- ducing inecpialities of the surface. Itasins lun[^i'(l dvcr ii pi't'cipice iilH)Ut two ImiidiL'tl I'uct liii,di, und foniu'd a cataract of tlic nature of Shoshone falls, Idaho, hut rivalinu^ Xianara in orandcur. 'l"\\o hasius were excavated in the rocks at the hase of the falls, which wcic left as lakes when the j^laciers retreated and the Columhia returned to its old channel. These lakes still exist althoutjh desert shruhs ^'row on the hrink of the precipice o\er which the watei-s of the flooded and ice-laden liver previously thundered. Each of the lakes is by estimate a mile lont,'' and half a mile broad, an.d of considi-rable depth, as is shown by the (hirk blue color of their waters when seen from the crest of the encircling clitts.i The deeper positions of stream channels excavated during floods, may be transformed into lakes when the waters subside or when the course of a stream is cL.u.ged. This is shown by the temporary i)onds remaining in many humid countries during droughts when water no longer flows through the customary surface channels, Imt is more common in arid regions where the streams are subjected to still greater fluctuations. 'I'he basins just deseiibed are formed principally by excavation, those noted below are due to deposition. In regions of rapid erosion, a high grade and conse(iuently rai)id tributary, may bring to a sluggish trunk stream more detritus than it is able to carr}' away. When this happens, the main stream is more or less c(»inpletely obstructed, and lakes may result, liasins of this nature occur in the steei)-walled valleys of the Sierra Nevada and Rocky mountains, and are to be expected wherever streams have cut back their trenches far into an u])land and receive liigh-grade tributaries. The alluvial cones about the bases of moiuitains in the Arid Region are frequently several miles in radius, and have a thickness near the mouths of the gorges from which the material forming them was dis- charged, of two or three thousand feet or more. When such deposits are formed on the opposite side of a valley only a few miles across, they may unite one with another so as to form transverse ridges and give origin to basins. Alluvial cones are especially conspicuous in regions where the drainage in the valleys is weak or entirely wanting, thus favoring the f(n'mation of basins in the manner just described. Lake Tulare, in southern California, may be cited as an example, as it is retained on a broad alluvial plain by material swept out by torrents from canons in the ' I. C. IJussell, 'Geological Keconnoissance in Central Washington," U. S. Geol. Surv. Bulletin, No. 108. I H have T cone ■I worls bodi( of ai 1 Rep., > OlllcaN Ol' LAKK liASlNS. "(1 ovev of till' Two •ll Wi'W (1 to its on tho :^e-la(U'n a mile 1 by the icircling )(ls, may ouise of niainin<>" er flows in arid IS. Ml, those ly rapid iiaii it is e or less no occur )untains, [1 ches far I Ke^ ■ion near tlie was dis- > )Osits are hey may origin to here the i iring the 1 uhirt , in ^ led on a ;i ns in the ''■ Geol. Surv. 1 Sierra Nevada. In regions where tlu' conditions are most favorahki foi' tlie gidwtli and [(reservation of alluvial cones, there is hut litth- rain-fall, and the material deposited in the valleys is apt (o l)e porous and of such a character that it ahsorhs water ii-adily ; for this reason lakes may he absent and the land remain desert-like and arid although basins exist. A lack of close adjustment in the transjtorting power of streams may sometimes he observed even in humid co ntrii-s, and in regions of mild relief. As described by (t. K. Warren, ^ the excess <»f material brought l)y ('hi[)peway river to the Mississippi, obstructs the main stream so a.s to c-ause an expansion of its waters known as Lake I'epin. An approxi- mation to the same conditions occurs where Wisconsin river and Illinois river join the " Father of Water.s"; but in these instances it is only in the low water stages that the ponding becomes conspicuous. A tendency in the same direction was noted by J. W. Powell while making his ad- venturous journey through the canon of the Colorado ; dangerous rapids were encountered at localities where lateral streams had swept debris into the main channel. Perhaps the best examples of lakes held by obstructions dej)()sited by lateral streams that can be cited, occur in valleys draining to the Assinil)()ine, jNIanitoba. The lakes referred to, are situated in valleys that Avere cut down to a gentle slope when the abundant drainage of glacial lakes flowed through them ; but the weaker modern streams are unable to maintain such a faint grade, and are being silted up where tributaries enter. Long narrow lakes are thus formed above delta-fans built by streams having a higher grade than the main valley.^ The .separation of lakes lirienz and Thun, Switzerland, has been cited liy Davis as an example of the partitioning of a valley by the union of deltas from opposite sides. Interlaken stands on the beautiful alluvial l)lain thus formed. Several other similar examples in central Europe have been described by various authors. Lakes retained by the dei)osits of lateral streams and by alluvial cones, pertain to young and immature streams, and are incident to their work of ei'osion. As topographic development progresses, these water bodies are obliterated, but when streams reach maturity and old age, lakes of another class ajipear along their courees. , .. 1 Am. .lour. Sci., vol. 10, .'M ser.. 1878, p. 420. - Warren Uphain, " Heport on Lake Agas.siz," Canadian Geol. and Nat. Hist. Surv., Ann. Rep., Tol. 4, 1888-89, p. 22 B. , -.,-. 8 LAKKS OF NOUTH AMKUICA. In th of mature sti that Ii It (1( th (I i-ti 111 tlic cose ot mature streams that Have eiu down me seaward portion of their valleys nearly to hase-level, that is aindoximately to the level of the oeeaii, and where rivers risinj,' in mountainous re^'ions tlow across low plains, it freiinciitly hapi)eiis that (lie more eiieifjfetii' tributaries towards tlicir head waters bring in more detritus than the <»'ently llowinj,' trunk streams are able to carry, and de])osition takes i)lae(! on their bottoms and over their Hood plains. When the main stream is floodcul and inundates its valley, its load is dei)osited most abundantly on the immediate bordei-s of its t'hannel, and builds up lateral embankments (»r levees. When this hai)[)ens, the latend tiil)utaries joining- the main stream in its lower eoui-se, may not be able to lill up their valleys as rapidly as the borders of tlie main river are raised, and are conse(piently ponded. Many shallow lakes have been formed in this manner along the borders ol the large rivers flowing to the (Julf of Mexico. The most eoiispicuous examples occur along the banks of I't'd riv.'V, Louisiana, where Literal lakes, as has been pointed out by Davis, are arranged along the side of its levees like the leaves on a twig. Ill the maturity and old age of rivers, when they meander in hroad curves through a wide Hood plain, as in the case of the lower .Mississi[)pi, the loops are frequently cut off, as shown on i'late 1, and erescent-sliapcil or "ox-bow" lakes are left. Kxamides of lakes of this chaiacter on a small scale may be seen along the border of many sluggish Inooks which traverse deei)ly filled valleys. Ill the formation of low-grade deltas, like those now in process of con- struction at the mouths of the Mississippi, Nile, Ganges, etc., the waters break through the levees of the main stream during floods, and form branching channels or "distributaries," which in their turn bifurcate in a similar manner, and build up their ehannels and inundated borders. In such instances low areas are frequently surrounded by embankments, and left as basins containing shallow lakes. Many examples of this occur- rence are found on the broad delta of the Mississipi)i. Of these Lake Pontchartrain is the largest at the present time. Lake Rorgne, in the same region, is another exanqjle, not yet completed. The delta lands of the Khiiie, in Holland, and of other rivers in northern Germany, contain many lakes and swamps of the type here considered. The celebrated Zuyder Zee was formed in part as a delta basin and in part by the con- struction of natural embankments adjacent to a low sliore. Miniatuiv illustrations of this method of forming l)asins may be seen on the delta> of many small streams, ])uilt in lakes and ponds. I I rd portion nx'l of till! icross low ■rt towiirds 'n\\r trunk ttonis and innndatL's tii bordem A'heu this Viiv I'oui'se, crs of tlu' How lakus r^e livi'is [ili's ot'C'Ur s has been 58 like the r in broixl .lississi[)pi, L'nt^sliai)e(l actor on a )oks whic'li ■ess of con- tbe Avators and form urcate in a mlers. In ments, and this occur- tliese Lake rne, in the Ita lands of ny, contain celebrated by the con- Miniature I the deltas L.VKKH OK NmiTI' AMIIItrA. Pl.ATK 1. • .^r" OX-BOW LAKES, LOWER MISSISSIPPI. 1 i li i 1! i i! OUKilN OF LAKK IIASINS. 9 The overloiuU'd strciiins from ohicii-rs mIs.) fmiii levees, in nuu'li the Siiine niiinner us in the ease of more mature streams, 'I'h'se emliaiik- meiits are apt to Ik; formed of hoth coarse and tuie material, and sometimeH enelrwe low ureas, so lus to ol»struet their drainage and give origin to lakes and ponds. Young streams, on account of the an)ount of dehris eon- triltuteil to them, thus in some instances, simulate to a certain degree the hehavi(U'of more mature rivei-s. Small lakijs of the class here ri'ferred to occur al)out the southern Iiorder of the Malasi»ina glacier, Alaska. h. liitx'niH f'linnrd l>!i inirrH ami runrntx. — Basins a'e fr» (piently formed along the ocean's shore and on the lM)rder of lakes, where sand and gravel '»ars have heen huilt across the entrances of Uiys, or extend from luailland t<» headland so as to cut off a curve of the shore. Numer- ous examples of water hodies that have heen isolated in this way, occur along the Atlantic coast and ahout the shore of the Laurentian lakes. The history of some of these secondary lakes may be easily read from the exceedingly valuable series of charts published by the II. S. Coast and (ieodetic Survey and by the U. S. Lake Survey. It frecpiently ha])- jjcns that lakes separated from the ocean by narrow sand bai-s, are fresh. This is due to tlie fact that the movement of water through the shore deposits is from the land seaward, and the originally saline waters in such enclosures have been flooded out. The seaward flow of underground water also exjjlains why fresh water may be obtained in wells on sand bars of the character here referred to. Besides living examples of the chiss of lakes liere considered, there are basins of a similar origin still to be seen about the borders of lakes that have ceased to exist. In the Great Basin, and esi)eeially on the bordei-s of the valleys formerly tlooded by the waters of lakes Bonneville and Lahontan, there are small lakes and enclosed basins not now flooded, which are due to the formation of embankments about the margin of those ancient water bodies. The valleys formerly covered with the water of these great seas to the depth of many hundreds of feet are now for the most part parched antl arid, and desert shrubs cover the em- bankments of sand and gravel on v, Inch the surf formerly broke. Only a few of the secondary basins formed along those ancient shores can be referred to at this time. At the town of Stockton, l^tah, about fifteen miles south of Great Salt lake, there is an innnense gravel bar, formed near the highest stage of Lake Bonneville, which sweeps comi)letely across the entrance of a valley and retains the waters draining from the southward, so as to form Rush n I 1© LAKES OF NORTH AMKIUCA. I !i!ill ill! m i'i lake. This lake is variable in area and (le})tli. Sometimes it measures two and one-half miles in breadtli and is about five feet deep ; aq;ain, during seasons of unusual drouglit, it eva})orates to diyness. Tlie bar to which it owes its origin rises one hundred and fifty feet above its surface, and under more favorable climatic conditions would retain a lake many square miles iii area. The view of the great bar at Stockton and the map of the same localitj^ presented on Plates 1 and 2, are so graphic and truthful that time need not be taken to des<;ribe them. Another ex.unple <)f a lake basin formed by a l)ar crossing the entrance of a lateral valley, is furnished by Lake Annie, near Fort Bidwell. Cali- fornia. The ancient hike on the l)order of winch the bar now retaining Lake Annie was constructed, flofxled Surprise valley, in the nortlieast corner of California, during Pleistocene times, l)ut is now represented by eyceediugly slialiow alkaliiie lakes. Lake Annie is a few liundred yards in diamcier, and is ke})t fresh and sweet by the escape of its surplus waters tlu-ough the endtankment retaining it. Perliaps the l)est of all the examples of the class of water bodies now under consideration, that can be referred to, i.j Humboldt lake, Nev.ada. This lake ()ccu[)ies a secondary basin in one of the valleys formerly flooded by the waters of l^ake Lahontan. When the ancient lake was lowered so as to approach extiiiction, a bar was formed directly across the end of Hum- boldt valle}', where it opens out onto the Carsen desert. The w'aters of Humboldt river were retained by this bar when Lake Lahontan fell so as to leave it dry, and a lake formed above it. The waters escaped across the bar and cut a channel, s(, as to partially drain the l)asin above; but in recent years an artiticial drain has l)een constructed in the opening, and the lake now covers a gi-eater area than it would had the natural con- ditions remained unmodilied. A map of the bar retaining HumboMt lake, on which much of the history of its origin can be read, is shown in Plate4.i .,-. ^,^: : ■ : . "^'.^ Basins ihw to }>rla('ial apr<'iu'i<>s. — On the surfaces of glaciers, esjie- cialiy on the lo\\er portions of n6\6 regions, there are frequently shallow depressions holding lakes which give variety and an additional charni to the. wintry landscapes with which they are surrounded. No ca.se is known in which these lakes are })L'rennial, although they foini in the same locali- ties year after yeai'. 'I'liey ai'e of little geological interest, for tlie reason 1 I. C. Hussi'U, " (^UiUeniary Ilistovy of Lake Lahontan," U. H. Gt'ol. Surv., Monograph No. 11. t I measures p ; aoain, The bar above its ain a lake skton and so graphic e entrance well, (-ali- ' retaining northeast spvesented ,v hundred its surplus )()dies now e, Nevada, rly flooded lowered so id of Hum- ; waters of tan fell so iped across ve ; but in ening, and itural con- Ilunibohlt 5 shown in eiers. espe- tly shallow 1 charni to e is knt>nn anie local i- the reason . , MuiiDgraph y.7^v ■m: ; liv / -» /■ ' //// ; / ■ 1 ' 'I'll" ##« ./,! i iV .a a. a u so 2, o 72 cr m _j t < c/5 < LU o o < r: - i < 9 CO S " -I O 2 O UJ ! i;r ■_a.jujJiiii i .Miii.irmr-r nnr immmm ::i Bl OltlGIN OF LAKE BASINS. 11 that they leave but slight if any permanent records. Their watera are so clear that practically no sediments accumulate in them. On conti- nental glaciers, however, such lakes might exist from year to year, and perhai)S receive sufficient tleposits to leave recognizable records after the ice disappeared. Certain deposits of exceedingly fine, light colored, clay- like material termed loess^ in the upper Mississipj)! valley, are believed by some [)ersons who have studied them, to have been accumulated in lakes on the surface of the great ice sheet which formerly covered that region. Wlicn glaciers flow through valleys surrounded by mountains, they sometimes obstruct the drainage of lateral valleys so as to cause lakes to form. The dams in these instances are formed by the ice in the main valleys. The type of this class of lakes is furnished by Miirjelen lake, Switzerland. In this instance a lateral valley l)elow the snow line is dammed by Aletsch glacier which flows past its mouth. The lake is variable in area, being sometimes a mile long and at other times completely drained owing to the enlargement of the tunnel beneath the ice dam through which it discharges. In Alaska there are many lakes of the Milrjelen type. About the southern bases of the foot-hills of Mt. St. Elias there are several water- bodies that are held in check by the Malaspina glacier. The largest of these, known as Lake Castani, at the southern end of the Chaix hills, is two or three miles long and a mile broad when at its highest stage, and discharges through a tunnel eight or nine miles long, beneath the ice sheet to the south. The position of this sulhglacial river can be traced by a depression in the surface of the ice, and when above it, the muffled roar of the impri;- ned flood can be heard far below one's feet. Of many lakes similar to Lake Castani in the same general region, perhaps the most instructive is one discovered by John Mnir, in Stikine valley, Britisli Columbia, near the Alaskan boundary. In this instance a lake about three miles long and approximately a mile broad, and receiving the drain- age of five or six residual glaciers, is held in a lateral valley by Toyatte or Dirt glacier, which flows past its entrance. The outlet of the lake is tlu'ough a tunnel in the ice, which is sometimes enlarged so as suddenly to cmi.ty the basin and cause a flood in Stikine river. , _ .. i^.^-, -. .. - The lakes formed when glaciers obstruct the drainage, hre variable ■in size, owing to changes in their draining tunnels, and are frequently emptied, as in instances just cited. The surfaces of these lakes are many times 'jovered witli floating ice, which is left stranded when their waters 12 LAKES OF NOUTH AMKIMCA. i Mi escape. They are unusually turlnd with silt ^wought to them by glacial stieams, and leave inii»ortant ^leposits to mark tlieir sites when the condi- tions are no longer favorable to their existence. The most widely known example of the formation of terraces about the borders of a glacial-dammed lake, is furnished by thf Parallel Roads of Glen Koy, on the west coast of Scotland. The origin of these terraces was a fruitful source of controvei-sy for many yeai-s ; but the explanation that they are clue to the taction of the Avaves and currents of a lake held in a lateral valley by a glacier flowing past its entrance, has finally been accepted as satisfactory. It is wortliy of note, that lakes of the type just desc-i'ibed, not only occur in mountain valleys, but also about the ends of mountain spurs jtrojecting int'i encircling ice sheets, as on the northern border of the Malaspina glacier. The deltas and terraces foimed in such lakes may remain in unexpected places, as high up on the side of a mountain, whei; the retaining glacier is melted. When the land bordering an ice sheet slopes towards tlie ice, the escape of the waters formed l)y the melting of the glaciei", as well as streams from the adjacent areas, is checked, and margin-'.l lakes, some- times of large size, are foimed. Two small examples of this class of Avater-bodies were seen by the writer at the northern base of the Chaix hills, vVlaska. During tlie close of the (Jlacial epoch, Avhen the ice-sheet occupying northeastern North America was retreating, there came a time when the southern margin of the ice faced a northward-sloping land- surface, and lakes far laiger than the present I^aurentian lakes, were formed. The largest of these ancient seas, named I>ake Agassi/,, covered the region in Minnesota and Canada now drained by Red river, and otliers were formed in the Laurentian basin. AVhen glaciers melt, the rock surfaces left exposed are frequently planed, grooved and polished. In such instances, the evidences of the friction of the flowing ice and of the sand and pebbles frozen into it, aiv ])i'()nounced and unmistakable. Tliese marks of abrasion are frequently buried and concealed by deposits of debris of various kinds which were transported on the surface of tlie living glacier o. enclosed in its mass, and left as superficial deposits when the ice melted. In the lower por- tions of mountain valleys previously occupied b}' ice streams, and over tin,' outer b(U'der of regions formerly covered by continental ice sheets, tlie deposits of d(?bris are in many instances so abundant that the worn rod; surfaces beneath are completely concealed. llii! iil hj glacial the coiuli- aces al)out llel Iloads se terraces xplanatiou ike held in inally been ci-ibed, not ntain spurs •dcr of the lakes may utain, when the ice, the , as well as lakes, some- lis class ol f the Chai\ the ice-slieet i-ame a tinu loping land- lakes, wen ssiz, eoveri'il d river, and e frequent 1\ ences of tin .'11 into it, au •e frequonth s which well in its mas-., le lower poi- imd over tlu' e sheets, tho he worn rock | '^i if i '4 ■ill ,1 Lakes of 'MoRTn America. PlJlTE 3. MAP HF THE PASS bet««en • RUSH AND TOOELE VALLEYS, UTAH. showing ihr WAVE BUILT BARRIER. By H. A. Vrh«»l«r. M A» OwiwiFf. MM 0f Jnr^mt Chmuktt, i^fiprvxf Vertical Section Trom jc to KuBh Lake STOCKTON BAR UTAH. (AFTER GILBERT.) Compare viith Plate 2. iHf ■"•^s,. II, i m ORIGIN OF LAKE UASINS. 18 The study Loth of livinpf fjlaciers and of the vocords left hy ancient ■ glaciers lias proven that Howing ice both erodes and dei)osits. and that ! basins ivsult from each of tliese processes. Wlietiier a ghicicr shall erode its beds or deposit material upon it, bcems to de[)end largely on it:' grade,, and conse(inently on its rate of flow. In high-grade valleys among mountains forn)erly occupied by glaciers, the higher and steeper portions of the main avenues of ice drainage, are usually intensely glaciated, and the worn and rounded surfaces are frec^uently bare of glacial dei)osits : l)ut the lower portions of such valleys, especially where they o})en out on a i)lain. are almost always heavily covered with morainal material. Not only are moiaines deposited in the mouth of the valleys, but .sheets of gravel, clay, and boulders are spread over the bottom of the glaciated troughs, showing that the iee- Streams in such situations deposited material on the surface over which Jhey flowed. t. Above the region of most intense glaciation in lofty mountains there is zone, embracing the higher summits, where polished and scrattdied jBurfaces are rare, and where there is but little debris. This ui)})er region was the site of the n6\-6s or snow fields of t'^e glaciei-s that abraded the rocks at a lower horizon and deposited their loads when the grade decreased and the ice currents were slackened. A similar association of region of glacial abrasion and an outer zone of glacial dei)osition, may recognized in countries formerly covered by continental ice sheets. In the region of most intense glaciation, in the case of both Alpine and fontineutal glaciei-s, as has been shown by extended observation, there ii'e numerous rock l)asins, the sides and bottoms of which are polished and triated. A large number of lakes of this character in the Cordilleran legion have been examined by the writer, and their study left no doubt tliat they were due to glacial action. These rock basins are confined to Weas of intense glaciation, and are absent from wljacent areas where the conditions are essentially the same, except that glaciers have not passed over them. It is impossible to point to examples where living glaciers are actually engaged in wearing out rock basins, since their work of abrasion is neces- sarily concealed; neither is it possible to satisfactorily observe the process T)y whieh glaciers polish and striate roi-k surfaces, yet no student of the subject doubts that these results are jtroduced by moving ice charged with sand and gravel. The nature of the evidence leading to the conclusion jat many rock basins are due to glacial abrasion, is of the same character ,oir 14 LAKi:S OF NORTH AMEIIICA. mi iiii! as the evidence from wliich it is coneludjd that many smootlied and stri- ated rock surfaces are due to the same agency. The rock basins of tlic cliaracter here referred to, are confined to regions of former glaciation, not only in America but on other continents, and are wanting where other evidences of ice action are al)sent. The interiors of tlie basins themselves are smoothed and striated, and bear incontestabhj evidence tliat in part at least, they are due to the abrasion of sand-chai'ged ice. These moic general considerations arc in sucli harmony with what is known of tlic woik of ice streams, that they carry even more weight than special studies of hidividual lakes. Although the evidence leading to the conclusion that many rock basins in glaciated regions are essentially of glacial <-rigin, seems to the writer to be conclusive, it is but just to state that, even after thiily years of ardent controversy, there is still a difference in o[)inion among geolo- gists and others, in reference to the abrading power of nioving ice, and its ability to erode rock hasins. The literature bearing on this question is so voluminous that it is impracticable to present even an abstract of it at tbr present time.^ \\'itbout considering further the results of the destructive action of glaciers, let us see what is the character of the basin they produce by construction. Fortunately in this connection there is little difference dt opinion. The terminal moraines left by Alpine glaciers in their retreat, fre- quently form crescent-shaped piles of debiis, convex down stream, whi( li act as dams, and retain lakes. Hundreds and })robably thousands ul exam[)les of lakes held in check by obstructions of this character, exist in the valleys of the Cordilleras, and are common in every formerly glaciat( il mountainous region. Tlie Twin lakes in the Arkansas vallev, C'oloradn.- several small lakes on the west side of Mono valley, California,^ ami numerous sheets of clear water in the Wasatch mountains, Utah, so well known to tourists, are types of this class. Similar lakes occur about tin 1 This subject has received special attention since the appearance of a celebrated pnjn : by Hainsay. "On the glacial origin of certain Swiss lakes," Quar. .Jour. Geol. Soc, vol. 1 p. ISo ; but a unanimous conclusion has not been reachec , .as may be seen by consult in. Nature for 1803-04. The present status of this interesting controversy is presented in pajier by T. G. IJonney, .and accompanyiufi discussions, in the Geoj.n^'aphical .Journal of '1; Hoyal Geoffraphical Society, vol. 1, 18'.):>, pp. 48l-o(M. • F. V. Uayden, U. S. Geol. .and Geoff. Surv. of the Territories, Ann. Hep., 1S74. p; 47-;"):!. .T. .T. Stevenson, ICxplorations and Surveys vrest of the 100th Meridian (" Win > Survey"), vol. :5, 1875, pp. 441-444. 8 I. C. Russell, U. S. Geo!. Surv., 8th Ann. Uep.. 188(1-87, I'l. .15. ' ; I I I, ■M I and stri- iis of the ition, not cvv ntlu'i iiemst'lves in part at lese more wn of tlif ui spLH'ial many i'<'*'l< i.nis to tlu' hii'ty ytii^i'^ iiong geolo- ici', and it> it'stion is SI : of it at til. vc action <> prodiK'e It.v difference of retreat, fr>'- eam, wliitli loixsands Lcter, exist in vly glaeiatt'l y. Coloradn.- iftn-nia,^ Utah, so u.'i cur about tlu celebrated pap*' leol. Soc.,vol. 1- een by consult in- is presented in al Journal of '' n. IU'Pm t«"^- V eridian (" Wb" < < > uj" < O CQ Z) X a z z < H a: QC < Q3 uJ > < >* '■<«*. OliKilN OF LAKK UASINS. 16 extremitieH of the existing' {jfliiciei-s of this country, from the Hi^h Sicini, Ciilifoniiu, northward to Alaska. 'I'hese arc retained liy moraines, from which the iee has reeeded within a few years, thus h-aving not even the 8ha(h)W of a (h)uht as to their mo(U' of origin. Many of the hikes of Scandinavia and of Switzerland are retained hy ancient moraines, as are also in part, the long, deep lakes on the Italian side of the Alps, and (haining to the I'o. The most striking exami)le of the type of lake here descrihed, however, Avhich has l)een studied liy the writer, is Lake Wakatipu, on the east side of the Soutiiern Alps, New Zealand. This magnilieent water body, surrounded on all sides hy lofty Bnow-cliid jtcaks, has many of the characteristic features of lakes Como and .Miiggiorc, and is not second to them in majesty and hcauty. The drainage of mountain valleys, in which moraine-ditmmcd lakes Ihave been formed, is frecpieiitly so ahumhint tliat stream channels are cut vMthrough the obstructions, and the lakes drained. When this occurs, .Px^autiful grass-covered vales or "parks,"' as they are called in the Rocky mountains, are formed. These charming valleys are (juite as beautiful and frcipiently furnish as gi'cat a contrast to the ruggcdness of the sur- .rounding scenery, as did the gem-like lakes that i)ri'ce(le(l them. In most instances the dcc[> mountain valleys of North Ameilca, low occupied l)y moraine-dammed lakes, were excavated by streams jrevious to being glaciated, and only served temporarily as avenues for Ice drainage. Their main toi)Ograj»hic features are due to stream erosion M,nd weathering. Oiny minor changes such as the smoothing and round- ig of their bottom contours, can oe ascribed to glacial ii.l)rasion. % The general sheets of debris left after the retreat of continental glaciera tnd by the melting of the expanded extremities of large Alpine glaciers, re usually uneven on account of the manner of their dei)osition. and abounds in de})ressions which may hold water. Jn many instances the lakes originating in this manner are without surface outlets, their sur- plus water escaping by percolation. I (^n the formerly ice-covered itortion of nortlieastern North America, fhe lakes occupying dejuessions in the general covering of superficial liaatcrial are so numerous that the position of the southern boundarv of fte old ice sheet may l)e approximately traced on a diaiuage map of the ^giou by noting the southern limit of the lake-strewn jjortion. The old land surface south of the glacial boundary, is almost entirely free from uiidrained basins ; any scjiiare miU's in an a. !n portions of Miinicsota, Michi^nm. and adjacent areas, whi-re tho drift is niiusnaliy dL't'[», the hdii's in irrcj^Mi- liir depressions on its snrface sometimes luimher a seore or more to th( wjnare mih'. It is estimated that in Minnesota alone, there are not U-ss than ten ilionsand lakes of this elass, l)esides many swamps and marshes marking the sites of former lakes of the same typ'e, whieh have heeonie choked with vegetation. Nnnii'rons lakt'sof tiu^ same charju'teras those on t'"' drift of \hv. Nortli- eastern Stales and Canada, oeeni' ahoiit the sonthei-n margin of Maliispiim gla< ier, Alaska, in (h-pressions in moraines left hy the retreat of the ice within the past few }ears. These very modern basins, some of whieh arc still ocen[)ied in i)art hy the ice of tho retreating glaeiei-s, are simihir in every way to the basins on tiie moraine-eovered snrfaces jnst referred to, and aiv snrronnded by topogrnphy of the same character, thus leaving no room tnr donbting that each of the two series is due to similar agencies. When the general sheet of d(5bris left after the retreat of continent;il glaciers does not completely nuisk tin' pre-giacial topography, foinici Vidleys are sometimes dammed, ar.d lakes of another type produced, in many instances these lakes are long and narrow, and indicate, to sonir extent, by their form, the character of the ancient drainage lines tiny occupy. Again, they may be broad water-bodies, and occupy ancieiii drainage basins, the outlets of which have been closed. Pre-glaci;il valleys may be deei)ened hy ice erosions, as well as obstmeted, and tin two processes may unite v<) form lakes, as is l)elicved to have been tin ease in the group of " '''ifi^,er lakes " in the central part of New York svatc' Still another type ox lake basins, due to glacial agencies, is found in unconsolidated v iter-laicl material ileposited about the borders of ict- sheets. When the stream-borne ddbris from a glacier is abundant it forms low alluvial cones and saiid and gravel plains, which may surro'uni or cover isolated ice masses. When such buried ice masses linally nul- a depression is left, and may be water-fdled. The boi'ders of su( h lal1" I.AKK ItASINS. 17 i\iuliv(ls of (lid watt'V- Miflii,!j;ini. ^ in inv^n- llOll! to 111* n; not loss 11(1 miirslK's ave become f llio Novtli- if Malii^l'iiiii t of lUe if«' 1)1' wliicli aiv lilar in overv lI to, autl nil' r no room for s. i coutinont;il apliy, t'oiiiHM vodiK'Otl- 111 •ate, to soUH' trc! linos tluV cupy aneieiu Pre-s^iiriM cted, and \h lavo been lli' sv York svati'.' ■s, is fonnd in )rders of i>'- abundant i' may suvvt>'uii'i es finally nul: of sudi lnl^»- il forms sttri on tlie natun of sand aii' Am. Bull., ve. Bull., vol. 5, IrfH gravi'l with liollows of tlic character just descrilted, .scattered over their Hurfaces, are known as "pitted plain.s," and tlnd their most accept;'d)le exphmation in tht' livpotliesis just su^'^'este voleniilc afjeneies. — Ine(|ualities on tlic surfaces f)f lava sheets sometimes giv;; vi.se to lakes in nnich the same manner as lakes are formed on the surface of glaciers. Examples of such basins in '^various stages of extinction, by drainage and sedimentation, occur on portions of the lava plains of Washington and Idaho. A lava stream may cross a valley so as to obstruct its drainage and fl*ause lake to form above it, in nnich the same way as glacici's dam " iteral valleys. A large lake was formed in this manner, proljably in 'leistocene times, on the Yukon river, Alaska, where it is joined by Pelly liver. A series of lava fli'ws there filled the river valley from side to side ito a depth of several hundred feet, and formed a dam which retained tfihe waters of the Yukon, and. gave v".rigin to a broad wattr-body known jlw Lake Yukon.^ The obstruction has aince been cut through along the Southern margin of the old channel, leaving a series of btusaltic precipices ^D the right bank of the river. 1 Warren Uphain, Bo.ston Soc. Mat. Hist., Proc, vol 2.'). pp. 228-242. ^ W. M. Dawsoi:, " lleport en an exploration in the Yukon district," Canadian r-eol. ^at. Hist. Surv., Ann. Hep., 1887-88, p. 132 B. I. C. Rui»spn, "Notes on the surface geology of Alaska." G^ol. Soc. Am., Bull. vol. 1, BOO, pp. 14(1-148. C. W. Hayes, "An expedition thro"gh the Yuk^^n district^" Natioaai Geog. Mag., 1)1. 4, 1892, p. 150. ii'ir .aimuiUiiLiiHTtilMIWili 18 LAKES OF NOUTH AMERICA. Another instance of the fonnation of a hake on account of the filling of a valley by a lava flow, hut on a nuu'h smallei' scale than the example cited above, has been observed l)y the writer, at the junction of Canadian and Mora rivers, New Mexico. Canadian river, for a distance of perhaps a hundred miles, flows through a steep-walled gorge, in which for a space of several miles, near where Mora river joins it, there is an inner gorge, as .iidicated in the following cross section : Fio. 1. — Cross Section nv the C'aSons of ('axahian am> :\Ioha KrvEns, New MEXiro (J. J. Stevenson;. The valleys excavated by Canadian and Mora rivers were filled to a de})th of 400 feet by basalt, as indicated by vertical lines in the section, and were subseiiuently eroded to a depth of 280 feet deeper than before the obstruction. The lake v.hich existed above the lava flow has been drained, and only indefinite traces of its former presence now remnin.^ Similar instances of the damming of streams by lava flows, are known on the west slope of the Sierra Nevada, but are also of .ancient date. The lakes that were formed have been drained, and their bottoms trans- formed into grassy valleys. Two small lakes, held in check by a recent lava stream, now exist at the Cinder cone, near Lassens i)eak, in northern California. Beneath the lava retaining these lakes there is a sheet of fine lacustral marl and dia- tomaceous earth, showing that a former lake was partially filled by thr molten rock, now hardened into compact basalt.^ Another class of lakes due to volcanic agencies, occupy the bowls of extinct cratei>!. These occur in various situations, being sometimes at the summits of high volcanic cones, and again in depressions in broad, featureless jjlains. The walls enclosing them are s;tmetinies formed of compact lava, but more fre(pi'}ntly consist of scoria, lapilli, and so-callcil ashes, blown out of volcanic vents during periods of violent eruption. 1 Thi.s instructive locality haa beeii described by .1. J. Ste.eiison, in Am. Phil. Soc, Proc, 1880, pp. 84-87. " J. S. Diller. " A Late Volcanic Eruption in Northern Celifomia. " U. S. Geol. Surv., Bulletin No. 7y, 1891. ORIGIN OF LAKE BASINS. 19 le filling example Canadian ; perhaps •r a space ler goi'ge, MEXiro filled to a l\e section, ban before \ has l)een emnin.^ are known cient date, toms trans- ow exist at beneath the ivl and dia- lled hy the le bov.'ls of (inetimos at ns in broad. s formed ot ud Ho-calk'il iiiptiou. Iiil. Socl'iw . S. Geol. Surv., At Tee Spring buttes, a group of small volcanic cratei-s, near Fillmore, I'tah, there is a pool of water in the throat of an extinc^ volcano, wliich ()('cu[)ies a deiJiession formed by tlie recession of the lava that once rose in and partially filled tlie crater.^ Tiie Soda ])onds on the ('ai*son desert, near Kagtown, Nevada, occupy lapilli craters, the linis of which rise 20 to 80 feet above the surface of the adjacent })lain. The larger })ond has an area of 208 acres and a depth of 147 feet, and its surface is 60 feet below the general level of tlie desert.^ A crater similar in character to those holding the Soda ponds, occurs on one of the islands in Mono lake, California, and is occupied by alkaline waters. The water within the crater stands at the same level as the sur- face of the surrounding lake, a connection between the two being main- tained by percolation through the intervening embankment of incoherent lapilli.3 One of the numerous cratei-s near San Francisco peak, Arizona, is said to hold a lake at a considerable altitude above the adjacent country. In the summit of Mt. Toulca, ^Texico, a deep depre.wion produced by violent eruptions is stated by Davis to have been similarly transformed. In many volcanic regions in other countries, lakes of this class are known to occur. They aiC common in Italy, o>i North Island, New Zealand, and are reported to occur in the Caucasus, on the Solomon Islands, in India, etc. A typical example of a water-filled crater is fur- lushed by Lajij^her See, on the border of the Eifel, Germar.y, and lias l)een described and illustrated l)y Edward Hull.* Still another class of lakes due to volcanic agencies occur where the summits of volcanoes have been blown away by the energy of the con- fined vapors within ; or when the base of a volcanic pile has been melted so as to cause it to subside into the conduit from which the material com- posing the mountain was extruded. It is believed that l)asins have resulted from each of these processes, but observations on their actual formation are lacking. It is known, however, that volcanic mountains of large size are sometimes literally blown away, as happened in the case of Krakatoa, in 188(5. ' (J. K. Gilbert. " Lake Bonneville." IT. S. Geol. Surv., Monofrraph No. 1, 1800, p. :J22. - I. C. Hussell. "Lake Lalxontan." U. S. Geol. Surv., Monof,'raph No. 11, 1885, pp. 72-80. * I. C. l{us.sell. "Quarternary History of Mono Valley, California." U. S. Geol. Surv., 8th Ann. Rep., 1880-87, p. ;173. ♦ " Volcanoes : I'ast and l»rescnt." Contemporary Science Series, pp. 122-123, ■r-^ w 20 LAKES OF NOKTH AMElilCA. n In several volcanic regions there are deej), circular depressions, known as " calderas " or " crater-rings," which are believed to have been formed by the blowing away of the mountains tliat once existed above them. A somev/hat complete series can 1>3 established between craters that have been pai-tially broken down by subsequent eruptions, and crater-rings, about which there are in some instances no vestiges of the oi'iginal craters remainintj. There is evidence also in the character of the rocks surround- ing crater rings, and in the adjacent topography, which sustains the hypothesis of their violent origin. Two of the largest calderas yet discovered, occur in Italy, and are occupied by Lago di Bracciano and J>ago di Holsena. As described by J. W. Judd, the first-named is nearly circular, Avith a diameter of six-and-a-half miles; the second, somewhat less regvdar, hfis a o-th from north to south of ten-and-a-cpiarter miles, and a breadtii of nine miles. The only examples of crater-rings in North America that can be referred to are Gustavila lake, Mexico, of which the wi-iter has been unable to obtain detailed information, antl Crater lake, Oregon. Crater lake has been described by C. E. Dutton,^ and is considered l)y him as worthy of a high rank among tlifi wonders of the Avorld. It is situated in the Cascade mou .tains, in northwestern Oregon, thirty miles north of Klamath lake, at an elevation of G239 feet al)ove the sea. It is nearly circular, Avithout bays or prf)mont()ries, as indicated on the accom- panying map, Plate 5, and is from five to six miles in diameter. Tlie cliffs of dark basaltic rock encircling it, I'ise precipitously to heights var}- ing from 900 to 2200 feet, and nowhere offer an easy means of access to the basin Avithin. They plunge at once into deep Avater, Avithout leaving even a platform at the Avater's edge Avide enough for one to Avalk on. There are no streams tributary to the lake, and no visible outlet. The Avaters probably escape by percolation, as the precipitsition of tae region is in excess of evaporation, and if an escape Avere not furnished the babiii Avould be filled to overfloAving. Near the soutliAvest margin of the lake, about half-a-mile from shore, a cinder cone, named Wizard island, rises from the Avater to a height »t 645 feet. This cone is regular in form and has a depression in its sum- mit, thus showing at a glance that :t is of volcanic origin, and is in fad a miniature crater of eruption. From the base of Wizard island two 1 Science, vol. 7, 1886, pp. 17t)-182. pp. 157-158. Also, 8th Ann. Rep., U. S. Geol. Surv., 1880-87, m T,AKFs OF North America. tz ris ' —10' 423li: 12ns k/stf CRATER LAKE, OREGON. (AFTER U. S. Geological Survey.) Contour-interTal 200 feet ; soiuidiugs in feet ; lake surface (iiUU feet above sea level. Il'ff^ il i OIIIOIN OB' LAKE BASINS. 21 streams of hardened lava extend outward towards the great walls enclosing the lake, but do not reach them. The sounding line lias shown that Crater lake has a maximum depth of 2000 feet and is the deepest lake now known in North America ; its nearest rival being Lake Tahoe. The full depth of the basin measured from the crest of the enclosing cliffs, is from 2i)00 to 4200 feet. The rugged slopes encircling the lake as well as the island that seem- ingly floats on its jdacid surface, are forest covered, thus softening and rendering picturcscpie the otherwise oppressive grandeur of the scene. More remarkable, however, than the unicjue scenic features of Crater lake, is the story of its origin. The site of the great de[)ression Avas once occupied by a volcanic niountain which reached far above the highest point on the cliffs now enclosing it. and was probably as conspicuous a member of the sisterhood of mountains of which it formed a part, as any of the neighboring peaks, but the once prominent i)ile has been removed so as to leave the profound gulf that now fascinates and stai'th;s the observer. The character of the sculptiuing on the outer sIojjc of the truncated mountain shows that it was eroded, both by streams and by j glaciers, before the catastro[)he that carried away its sunmiit and left only a hollow stump to mark the site of the ice-crowned peak that formerly gleamed in the sky. The removal of the summit of the mountain is supposed to liave been [due to a mighty explosion, similar to that which ])lew off 5000 feet from [Krakatoa ; or else that the mountain was melted from within and its [summit engulfed so as to leave the depression now partially filled with [placid waters. Of these two hypotheses, the second seems to accord best Iwith the observed facts, for the reason that fragmental deposits on the svuface of the adjacent country, of the character that would be exj)ected lad the sununit of the mountain been blown away, have not been recog- jized. Subsequent to the removal of the sununit of the mountain, •newed volcanic energy of a mild character built the c .iter-island within |;lie crater-rinsf. A circi lar depression in but little disturbed stratified rocks wliich cars some reseml)lance to a crater-ring, and which seems likely to furnish le key to the origin of the cable ras of Italy and other regions, lias jcently been discovered in Arizona, about 25 miles southeast of the )wu of Flagstaff. This unique basin has been carefully studied by i. K. Gilbert, but no account of it from his pen has come under the rriter's notice. The observations stated l)elow are mainly from a *>o LAKES OF NOUTH AMERICA. i|';:|;M; M description of a model of the locality published in the American Geologist.^ This " crater " in what is known as Coon butte, is three-fourths of a mile in diameter and its l)ottom is depressed from 500 to {WO feet below the encircling rim, which rises 1 50 to 200 feet above the surrounding plains. The surface limestone of the region, elsewhere horizontal, is steeply inclined quaquaversally in the cliffs around the crater ; and masses of the samn stratum and of an underlying sandstone, are strewn in irregular profusion outward from the crater to the base of the butte, which has a diameter of about two miles. In leps amount, the same debris reaches outward on all sides over a nearly circular area to a distance of about four miles. No lava, bombs, lapilli, or other vol- canic products, Avere seen. The formation of this irregular crater-like de})ression is referred by Ciilbert, perhaps provisionally, to a steam explosion. The occurrence in the vicinity of Coon butte of hundreds of fiag- ments of meteoric iron, up to about a pound in weight, and of several l)ieces weighing from 20 to 600 pounds, led at first to the thought that possibly a meteorite of great size might have struck this spot, buried itself out of sight and thrown up a crater-like rim. This hypothesis, upon being tested, was abandoned, however, because the volume of the raised rim and of the rock fragmentb scattered about, was found to corre- spond very closely Avith that of the depression below the level of the plain : and for the second reason, that a magnetic survey failed to indicate the existence of any large mass of meteoric iron competent to make such a crater, within at least a depth of many miles. This second objection, however, is now considered of but little weight, since the meteoric fragments found about the crater, although now magnetic, have undergone alterations of a character which seem to indicate that when they first reached the earth they might not have had any or but slight magnetic properties. The changes produced in the surface frag- ments are due to atmospheric influences, which would not reach a deeply buried body. The crater-like depression in the summit of Coon butte is without water, for the reason that it is situated in an arid region, but under humid skies would no doubt be transformed into a lake. The only counterpart of Coon butte as yet discovered, is situated in the central part of the Peninsula of India, some 200 miles northeast of 1 Vol. 18, 1894, p. 115. 'IW6 OIMGIN OF LAKE UASINS. M Bombay. Tliis remarkable crateriform lake, known as Lonls lake, is described by K. I). Oldbam ^ as follows : "Tlie surrounding country for bundreds of miles consists entirely of Deccan tra[», and in tliis rock tbere is a nearly circular hollow, about 800 to 400 feet deep and rather more than a mile in diameter, containing at the bottom a shallow lake of salt water without any outlet, whose waters deposit crystals of sesquicarbonate of soda. The sides of the hollow to tlie north and northeast are absolutely level with the surrounding country, while in all other (bisections theie is a laised rim, never Acced- ing 100 feet in height and fretiuently only 40 or oO, composed of blocks of basalt, irregularly piled, and [)rt'cisely similar to the rock exposed on the sides of the hollow. The dip of tlie surrounding traps is always from tlie hollow, but very low. "It is dillicult to ascribe this hollow to any other cause than volcanic explosion, as no such excavation could be produced by any known form of afpieous denudati(tn, and the raised liin of loose blocks around the edge appears to preclude the idea of a simple depression. It is true that there is no sign of any eruption having accompanied the formation of the crater ; no dyke can be traced in the surrounding rocks ; no lava or scoria'^ of later age than the Deccan trap period can be found in the neighborhoo(.. The raised rim is very small, and cannot contain a thousandth part of the rock ejected from the crater, but it is imi)ossil)le to say how much was reduced to fine powder and scattered to a distance, or removed by denudation. " Assuming that this extraordinary hollow is due to volcanic explosions, the date of its origin still remains to be determined. That this is long posterior to the epoch of the Deccan traps is manifest, for the hollow appears to have been made in the present surface of the country, carved out by ages of denudation frcnn the old lava flow. To all ai)pearauce the Loiuts lake crater is of comparatively recent origin, and if so it suggests that, in one isolated spot in India, a singularly violent exfJosive acti(m must have taken place, unaccompanied by the eruption of melted rock. Nothing similar is known to occur elsewhere in the Indian Peninsula." Besides the obstructions to drainage produced by overflows of lava, and by volcanic explosions, it may also be not'l that volcanic dust and ashes, ejected from volcanoes during times of violent eruptions, may be deposited over the adjacent country in such a manner as to choke the streams and possibly form dams which would retain lakes. This process » " A Manual of the Geology of India." 2(1 ed. Calcutta, 18!t:]. pp. 19, 20. a: ill lliil ;i: 1 III lis: ll 24 LAKES OF NORTH AMEUICA. has already been referred to ia connection with the formation of 1)asins through the action of eolian agencies. Lava streams frequently cool on the surface while the liquid rock below is still flowing. In such instances, when the crust is sulliciently strong to sustain itself, the molten lava beneath flows out, leaving caverns. Openings of this nature may become water-filled and form subterranean lakes, or their roofs may fall in, leaving depressions open to the sky. Lakes and ponds occupying such depressions are thought to exist on tlic vast lava sheets of Oregon, Washington and Idaho, but clear, simple exam[)les of the type are not at hand. On a small lava flow on an island in Mono lake, California, there aic depressions occupied in part l)y water, which are due to a general sul)- sidence of the surface on account of the outflow of molten rock below and the crumpling of the crust into concentrir, crescent-shaped ridges. Another mode in wliich volcanic agencies may produce depressions is by subsidence of the surface about volcanoes, due to the removal of lava from subterranean reservoirs, but no instances where this has certainly occurred have yet been observed in this country. Ilasiiis due to the iir .ict of meteors. — The study of the origin of the crater-like forms on the surface of the moon recently made by Gilbert.' was suggested by the hypothesis that depressions on the earth's surface might result from the impact of meteoric bodies. This suggestion has already been referred to in describing Coon butte, and is one of great interest. Up to the present time, however, no basins on the eartli's sur- face are known which can be ascribed to this agency. If the earth was formed by the coming together of a large number of previously independent meteoric bodies, as is thought to have been tlie case by Lockj-er, all evidence of such an occurrence in the relief of its surface is wanting. Small meteors are known to reach the earth every day, and a number have been discovered weighing many tons, but suth an event as the earth coming in contact witli a planetary mass a mile i»r several miles in diameter, as seems to have lia^jpened in the case of the moon, is not only unrecorded in history, but, as just stated, there is w evidence in the surface features of the earth to show that such :ui event has happened in recent geological time. If the earth once had a pitted surface, like the moon, and was scarred b}' vast crater-like i"The Moon's Face," I'hilosophical Society of AVashiiigton, Bull. vol. 12, 1803, pr -| 241-292. ORIGIN OB' LAKE IJASINS. 25 .ear, simple depressions, each one the record of the piercing of its surface and the hurial within its crust of a planetary mass previously rcvolvinfi; independ- ently in space, the date of the last of the catastroi»hes which produced that condition must hf,ve heeii so remote that erosion has removed all surface evidence of the fact. Still farther negative evidence may he cited, inasmuch as no buried meteoric masses recognized as such, have been found in the rocks now forming the earth's surface. This is r.ot proof, however, that the meteoric hyi)othesis, as applied to the earth, is not true, as the main events in that drama are assumed to have been enacted befo"o, the formation of the stratilied locks now recognizable. krol. 12, 1893, m' Basins due to cnrtliqiiakcs. — During earthquakes there are undula- tions of the surface of the regions aftected which sometimes produce pei- inaiient elevations and depressions and thus affect the drainage. The passage of earthquake waves through loose deposits may cause them to become more compact and perhaps jjioduce depressions on their surfaces. In these and probably other ways, basins may be formed by eartluiuakes and give origin to lakes. The best examples of lake basins in America, resulting directly from eartlujuake shocks, occur in what is known as the "Sunk country" in i southeastern Missouri and northeastern Arkansas. A series of severe disturbances, known as the New Madrid eartliquake, affected that region between 1811 and 1813, and caused both elevations and dei)ressions in the forest-covered flood jjlain of the Missi.s.sip[)i. This region has recently [been examined by W J Mc(tee,^ who reports that a low dome some 20 miles in diameter, was upheaved athwart the course of the ^Mississippi and that [the river was held in check for a brief period, but soon cut a channel [through the obstruction. An adjacent area some one hundred square [miles in area, was de[)iesse(l and is still, in i)art, occupied by lakes in which the trunks of trees killed by the inundation are standing. During eartlKpiakes in regions occupied by unconsolidated rocks, ater is sometimes forced to the surface with great violence, probably on iccount of the compression of porous, water-charged strata, and lises l^ountain-like above the surface. The water brings with it quantities )f sand and mud which are deposited around the points of discharge and kerve to enlarge the depressions produced by the violent outrush. When fountains cease to play these small cratei-like basins remain as ponds. 1 "A Fcssil Earthquake," in Geol. Soc. Am., iJull., vol. 4, pp. 411-415. ■r- 26 LAKKS OF NOUTM AMKIMCA. Itasiiis duo to orf^aiiii- ajf<*i"«'i<'f*. — The study uf coral reefs lias shown that bodies of sea water are soiuetiiiU'S cut oft' from the ocean. althou<^di rarely coin|)letely se])arate(l, hy the j,'rowth of reefs of liviiiLj coral adjacent to coasts, or as atolls about isolated islands and "banks." liakes of this nature perha[)s occur at llie south end of Florida, and on the West India islands, but no well delined instances have been described. The formation of peat in temperate latitudes rffords another illustra- tion of the mannei- in whicli orjijauic agencies lead to tlie formation of lakes. The growth of the moss known as Sjihai/nuiit, from which peat is largely formed, may ()l)struct sluggish drainage ; and its une(|ual growth in swampy areas leads tf) the formation of mounds with dei)ressions in their sununits. '1 he best known illustration of this type is Drummond lake, in Virginia, but many' smaller examples occur in other swampy areas. It has been suggested that the basins in peat swain})S may havt' originated by the burning of the bogs during times of excessive drouth. That this might happen is evident, but no authentic case of such an occurrence is known to the writer. On the vast tundras skirting the Arctic ocean in both the Old and the New World, there are vast numbers of ponds and lakes held in depressions in the frozen bogs, and surrounded by banks of moss and other vegetation. These water-bodies have probably originated in various ways, but in some instances their birth may be traced to the luxuriant | growth of vegetation in s})ring and early summer about the borders of "j liuLferiufj snow banks. When the vegetation of the tundras awakens after its long winter sleep, its growth is sur])risingly rapid, and the snow drifts that last longest are surrounded with luxuriant mosses and brilliant flowers. When such accunudations of snow finally melt, the vegetation on the areas they occupied is less in amount than on the surroundinu- | surfaces. The tundra increases in depth by the partial decay ani';,'aiii(' arodnced important ehauffes in the minor features of the surface )f the continent. .Many of these ponds, after heeoming ehoke(l with iref,'etation and conveited into peat swamps, have been drained and furnish rich garden-lands. Where brooks and ereeks How tlm .;h forested regions, it fre- quently happens that large trees fall a( r(».ss them and retain the sticks id leaves swept along by the current. When sueh a start is nu de, the uid carrittd, especially during freshets, is lodged among the leaves and ranches, and tends still farther to obstiuct the drainage and lead to the Munition of swamps and lakes. This process has been obseived espe- lj)lly in Red river, Louisiana, where timber rafts several square miles in 3a, and covered with living vegetation, form floating islands and dam ^e streams so as to cause their waters to si)read out in shallow lakes irenty to thirty miles in length.* Numerous instances in the Yukon river, in Alaska, were observed by |e writer, where lateral branches of the stream and the passage ways Itween islands, were closed by accumulations of drift logs that greatly strueted the flow of the watei-s. In some instances these acjumnlations, olllcd " wood yards " l)y steamboat men, are several acres in extent. Still another way in which oiganie agencies lead to the foiination of bteins may be ob-served in swamps where vegetable matter buried beneath nWJ'l iind clay is undergoing decomposition. Openings similar to those produced in alluvial dejxtsits by the violent escajje of water during earth- q^kes, but not necessarily connected with such disturbances, are formed iil;:^narshes by the violent esca])e of gases from below. Instances of this oeeurrence have come under the writer's notice on Smoke Creek desert, ■ ^. ,Z} Charles Lyell. " Principles of Geol()<,'y." 11th ed., Vol. 1, p. 441. Iluinplirey.s & Abbott, ort oil the Physics and Hydraulics of the Mississippi," Professional Papers, Corps of eers, U. S. A., 1801. p. S7. I'jlTf* a^ ^^ 28 LAKKS OK NOltril AMKIMCA. Novada, and «>Il s\v unpv uvas lu'ar Suiitliisky, Ohio. Wht-n tlu'sc ,ljas t'ruptioiis oi'i".'.!', till' soft luud is soiiu'liiiu's throw ii to a tlistaiicc of oiic or two Imiidivtl fcot, ainu'oiMi'al dopri'ssioiis ari' foiim-d wliicli in soiin' of tli iiistaiU't's ohsiTvi'd, art' twoiily fi't't or moic in iu'|>tli. Tl u' i-aviiii;' 111 o tlu' l)anks' lioh's sonu'timt's h-ads to tlu' foniiatioii of pools lifty or sixt fi'i't ill dianu'tfr. llu' riirular poiuls fii'i[iii'iitly to lu' si'i'ii in s\vaiii|) n>i^ions, wlii'ii not diii' to riu'roafliinjjf vi'iji'talioii, probably, in iis:iii instaiu'i's, on_L;iiia ti'.l 111 liii' inaniii'r iifif noted .11 'I'l'.t' n'l'ncration of Ljascs, iirinripally iMihnri'li'd liydroL^cn. in tlif s( mud of till' Mississippi tU'lta, lansi-s ch'vations known as " mud liiiiips. ' ■wliirli in sonii' instaui'i's ari^ Iwt'Uty-livf feet lii>;h. Iiit'ijualitii's pro duri'd in tliis maniu'r miijlit rasily lead to the obstriution of draiuai;i' and till' formatioK of laki's, hut no instance of surli an ofi'iirivui'i' soi'ni-< toh lavo hi'i'u ri'poi ti'd. IM It lias fivqufutly hi-fu ohsorvfil tluil cittlr on visiting; swampy plai^ carry away i-onsidi'riihlo iniantitii's of mud, Millu'iiii!:;- to tlu'ir h't't a matti'd ii; tlu'ir hair, in arid conntrii's wlit'ii' diinkint;' placi's vav usually ill and wiiU'lv si-atti'i'i'd, tlu'v ari' visited hv liitth' iind otlu'r animals in (tin larLji' nuiulu'is und a marked onlaroiMU'nt of tlic water lioli's is prodnrc in till' nianui'r just stalfd Tl lis proci'ss was mori' important wluii thi' plains of North Anu'rira wi'ii' dt'iisi'ly inhahiti'd hy hisoui- M; inv pcri'unial [lools and still nioit' nnmi'rons di'pri'ssious that an' wati'r-tilliil ojily durinjjf rainy seasons, air k-iown as " hulValo-wallows," and ;ii\ b»>lii'\rd to owe thi'ir orii;in to a <;ri'at I'xti'iit to thf earryiiiij away ol mud I'litanu'lid iu the thiek hair of the animals nfter whieh they iiiv named. In the Appah.iehians there are several water holes, usually on tl 'rests of ridties, that are ealled "hear-wallt )WS, md are said to h; n 1 been formed by beaix that sonn'ht m»)ist plaees in whieh to eool tlie.ii Helves 'Uiruig lint we habit. lit! lor. IS is wi 11 1. viiown, sw ine 1 lave a siimkir HnNlns urin«;' the jfrowth of mountains it sometimes hap(tens that tluj rejjfioii iH'tween difVen'ut systems or between two or more ranj^es, beeonnv eni losed so as to form a basin. This proiiess has Ikhmi in aetion in varieii- loealities siiiee hind first up(>eared. and durinjj; the eoursi* of ijeohioieal eiu<| OUKUN OF 1,AKK UASINS. tht>s(> Ljiis dl' Diu' or )UU' t>t till' tvini;' ill "t ty or sixtv 11 s\viimii\ , in iii;ui\ in till' soft ul lumps.' iilitios pro- )t" ilniina^r VIU'C SOlMlls impy pliUHs ir I'l'i't ;ini i.io usually r aiiiumls in is pnuluind rtaut wlu'u us. Maii\ wattM'-tiUttl iiiul arc ins;' away ol •h lliry arc tally »>n tl'l uiil to lia\c vo()l tin. Ill •(> ;i simihii'l rhauijcs ml hilo smallcij .)uutait\s anil| H'us that tl .•OS, luH'tUlll'^ )ti iu vanoi^i must liavo tt'sulti'd in tlu> loiiuatioii of luaiiy lakes; hit' cxainplos of wutor Iiodii's of this typ(> aiv laiv at the pfesont tiiiit'. ptiini|).illy l"(U' the ivasou iliat the (It'i'oiiitatioii o{ the earth's ciust ttsiially y-oes on slowly ittttl the (leptesslotis fotiued ate ihaiiinl »tr lilleil with se(limt'iil.>> its rapidly as they are formed. IMie liest I'xamples on this et)tititient of hasitis fortned hy the upheaval of moiuKains around tlu-ni, oecitr in the L;'reat area of interior (lraiuay;o hetweeii the Koeky iiKUintains and the Sierra Nevada. The majority of till' minor hasius in this reyioii, however, ari- diu> to .seet)ndaiy tause.s, hut the vast seas, sneli as lakes noiuteville and Lahoutan, wliieli h>r- merly existed there, (u cupit'il hasius of the ehaiaeter here referred to. 'riu> Latireutian hikes are ludd in hasius produt'ed in part hy i-rustal iiiovemeiils alVeitiun' lai'oe ait'as, and in part hy eoiulilions ri'suliino- from other causes. l>asins art' also produced \)\ less extensive elevations and depressions of the earth's i-rusi. The corrupttion of a rcLjiou, o\\ iu^;' to I m the hirmation of a scries of approxim;itely parallel folds, known as anti- cliiials and syiu'liuals, as iu the ease of the Appalachian mountains, must fretpieutly produce hasius in which water wouhl he ri'lained, were the process allowed to yt) on witlnmt some eouute-ai'tiui^' ai;ency ; hut hero auain, the movemeuts are usually so slow that, es]tecially in hniuid regions, till' depressions produci'd are destroyod as rapidly as they are formed. While lakes iu syiu'liual hasius luiohi he ex|ii'cted to hv of common occur- rence, they are in reality si> rare that, so far a.. 1 aiu aware, none of the tens of thousands of the lakes of America can ho pointed to as examples. 'I'hero is still another variety of earth inoveiiu'uts iu many instances less oiadual than thi>se referred ti» ahove, to which utauy lakes owe their ori^'in. Fraetures in the earth's crust oi-cur in disturhed rejifions and may he scores or even hundreds of mih's in Iciiotli. 'I'ho edsfcs of the hrokeii I strata on one side of a fracture are somi'times elevated, or those on the opposite sitle depressed, thus torminn' what is known as a " fault." 'I'ho U>'rowth of faults som»'(inies i^oes on so slowly that no pronounced chaujjes in to|)ooiaphy result, for the reason that the rocks on the upheaved side [of tlu' fracture are eroded away as fast as they are raised. .\t other Itimes. however, uiouutain rani>i's are [H'oduood, in whiih the strata are linclin. (i av, ay from the steep, hrokeu face overlookiiij^; the lino of fracture. Ilii reL;ioU8 where sui-h mountain ranees have hceii formed with comjnuativo |rapidity and where deiunlinjx aijeneies are weak, yreat disturUuiees in tlio Irainaufo result, and "fault hasius" are common. Nuiuorous husins of ■w^ 80 LAKES OF NOKTH AMP:KICA. this character occur in the Arid region and especially in Nevada ami sontheastern California, but probably the most typical example is the one occupied by Abert lake, Oregon. Along the east side of Abert lake there is a long line of magnificent piilisades, several hundred feet high, formed by the precipitous face of an eastward dipping fault Ijlock ; the lake washes the base of this escape- ment and occupies the depression formed by the subsidence of the rocks on the west side f)f the fracture. Sinnething of the appearance of Abert lake, as seen from the crest of the palisades a few miles to south of its southern end, and also of the general structure of the iniderlying rocks, may be gathered from the accompanying illustration. The lake is about fifteen miles long with an average width of nearly four miles, and is shallow. It receives the water of a single creek, but does not overflow and is intensely alkaline. Many of the lakes of the ^Vrid region are of the Abert type, but usually the great depressions in which they occur have become deeply filled with the sediments of older water bodies, and they may be considered as occupying depressions on ne\v land areas, or as belonging to the class of basins here consulered, as one prefers. In some instances the faulting that gave origin to the characteristic topography of the Great Basin region has been continued to the present time, and produced escarpments across the bottoms of the deeply tilk'd valleys, so that the existing water-bodies are confined in jiart by recent fault scari)S. An instance of this nature is furnished by Mono lake, Cali-! fornia, which washes the base of a precipice formed by a recent movement I of the great Siena Nevada fault. A similar association has also been observed in coinieetion with several of the lakes of western Nevada. When a fault crosses the course of a river, the edge of the upturned block may rise so slowly that the stream is able to maintain its course j and cut a channel through the obstruction as it is elevated, and a lake isj not formed. Numerous instances of this nature have been observed by the writer in the central part of the state of Washington, where tlu'| Columbia and the Yackima river have eroded deep narrow gorges tlirou<(li M the edges of fault blocks that were upheaved across their courses. With basins produced by faulting, as in other instances of surfiut| ine(|ualities due to movements of the earth's crust, the question whether lake vvill be formed or not, is ansA\x>red mainly by the climatic conditio! in 2 In aril regions the surface effects of orographic movements are countii- acted by erosion but slowly; while in countries with abundant drain;e4' ORIGIN OF LAKE BASINS. M degradation goes on energetically, and nnless the deformation of tl.e surface is coni[)aratively rapid, no pronounced topograj)hic changes result. It is the '-atio between the rate of deformation and denudation which de- termines whether basins shall be formed or not. Evidently tlie most favor- able regions for studying the effects of movements in the eartli's crust on tlie surface relief, are those in which the meteoric and aqueous, agencies are least energetic, namely, in arid regions. Basins due to Innd-slldoH. — On steep slopes great masses of rocks and earth not infre»iuently break away, especially after heavy rains, and descend su(hlenly as hind-slides into the adjacent valley. .When this occurs, the drainage in the valley may be obstructed so as to ca\ise lakes to form. Avalanches of snow and loose rocks also produce similar results, but of a less pronounced character. Small lakes originate in many cases on the surface of land-slides owing to the fact that such surfaces, after the descending mass has come to rest, usually incline toward the clitfs from which they l)roke away, in such a manner as to enclose ])asins. At times, a lanil-slidc plows up the tioor of the valley into whieh it })lunges and forms a ridge, not unlike a terminal moraine, Avhicli may also act as a dam and hold a lake in check. . Examples of l)asins formed in each of tliese several ways have been examined by the Avriter in the state of Washington ^ and in other regions, but need not be described at this time. JBnsins due to chemical action. — In limestone countries the <1 inage is often subterranean and finds its way through caverns formed by the solution of the rock. The roofs of such caverns fall in as the general erosion of the region progresses, and obstruct the drainage channels so as to form lakes. The surface waters reach imderground channels througli openings termed " sink-lioles," or "swallow-lioles," which are enlarged by solution, and frequently become closed so as to hold pon(h:. In portions of Kentucky and througliout the (ireat A^jpalachian valley, where the underlying rock is limestone, circuhir jjonds of this nature are so numer- ous that they give character to the landscajje. Lakes also occur in the caverns themselves, owing to various causes, the most fre([uent I;eing the ; falling of portions of their stalactic roofs, as may be seen in Mammoth jftnd Luray caverns. ' "Geological Uecnmidissancc in Central Wasliiiigtnii," U. S. Gcol. Siirv., Bulletin No. I.18. H 82 LAKES OF Basins of small size, due to chemical precipitation, occur in connection with sj^rings that deposit calcareous tufa or siliceous cinter. Many ex- am])les of pools formed in tliis way occur in the Yellowstone National Park and in other hot s])ring regions of the Cordilleras. Near the Avesi shore of Mono laite, California, there is a castle-like bowl of calcareous tufa^ fully 50 feet liigh and from loO to 200 feet in diameter, Avith several long aqueduct-like branches, which was formed from the water of a sprini; that has now ceased to flow. Far out on the desert valleys of Utah and ^ vada one sometimes finds circular basins with rims of tufa from a few inches to three or four feet high, and holding beautifully clear water with a temperature approaching the boiling point. In othei instances, thesr deposits rise several feet above the adjacent surface and resemble volcanii craters. In their sununits there are frequently steaming caldrons. In regions underlain by gypsum, rock salt, and other easily solul)lr substances, depressions are formed on account of the removal in solution of the rocks beneatli and the subsidence of the surface. Gypsum is thought by some geologists to owe its formation to the alteration of limestone by the passage through it of sulpluirous gases or of sul2)hurous Avaters. When this occurs, the volume of the deposit is , increased and the ground above may be elevated into mounds, and thu« obstruct the drainage. CONCLUSION. In this chapter an attempt has been made to describe briefly the principal types of lake basins occurring in North America, to indicate the processes by which they have been formed, and to sho\r to some extent, 1 where they severally belong in the history of topographical development. Many basins have resulted from the action of more than one agency, i and in not a few instances several agencies have coiiperated in their h production. Basins of a composite character have thus originated, butj the principal cause leading to their existence is usually so pronounced that when carefully studied, they may without great violence be referred to some one of the types here described. The study of lakes has shown that they frequently have a long and syj ire described CHAPTER II. MOVEMENTS OP LAKE WATERS AND THE GEOLOGICAL FUNCTIONS OP LAKES. Tides. — The waters of lakes are influenced by the attraction of the sun and moon in the same manner as the waters of tlie ocean. Giving to the comparatively small extent of inland water-bodies, however, the rise of their waters is so small that it is not noticeable, and can only be determined by refined measurements. Observations made by the U. S. Lake Survey at Chicago, have shown that Lake Michigan has a tide with an amplitude of 1^ inches for the neap tide and 3 inches for the s|)ring tide. "Waves ami eurronts. — Tlie waters of fresh lakes respond to tlie influences of the wind more (piickly than the heavier waters of the ocean, but the waves produced are smaller and less regular than in the open sea. On the Laurentian lakes, waves from 15 to 18 feet in amplitude have been observed during long continued storms. The heavy ground swell of the ocean is but faintly reproduced by the fresh water "seas." During rough weather on tlie lakes the waves are more like the short, "cho]) seas " than the heavy surges of tlie open ocean. The friction of the wind on the surfaces of lakes ])roduces very decided movements in their waters. In their central portions, especially, there are frequently strong currents due to this cause, in addition to the slow movement of the waters toward an outlet. A study of the currents of the Laurentian lakes has been undertaken by the United States Weather liureau, by means of bottles containing a record of the locality where tlicy were set adrift and a request that the finder will note the locality where they are recovered ami transmit the record to the Chief of the Weather Bureau. The results of observations made in the sunnner season of 1892 and 1893, have been published,^ and the general coui-ses of the : currents so far as ascertained, indicated on a chart which is reproduced on Plate 7. The eft'ects of the prevailing westerly winds on the surface movement of certain of the Laurentian lakes, is indicated by the trend 1 U. S. Department of Agriculture, Weather Bureau, llulletin B. fW^ 34 LAKES OF NORTH AMEKICA. iiiliiiil lll;i!K '■'\m: of the principal curreuts. When the hirger axis of a lake coincides with the direction of the prevailing winds, a surface current is established thiough its center, as in the case of lakes Erie and Ontario, with return currents and eddies along the shore and about islands. When lakes lie athwart tlie prevailing winds the main currents combine with the return currents and form minor swirls, as is shown on the chart in the case of lakes Micliigan and Huron. In Lake Superior there is a general circulation which follows the main shore lines, but its couree has not been fully deterniined. It has been found that the currents of the Laurentian lakes have in general a speed of from 4 to 12 miles a day, but in certain observed instances, this is increased to 2i- to 4 miles an hour or from 8(! to 9tt miles a day. The cujreuts in the central i)art of a lake produce slight if any changes on the topography of its basin, but when they follow the short' important results may follow. When the wind blows obliquely to tht; shore, strong currents are frequently produced which follow the general trend of the coast, but cut across bays and inlets. These currents, with the assistance of waves, sweep along sand and gravel, and produce im])or- tant changes on the bottom, particularly when the water is shallow. Tlie role played by waves and currents in modifying topography is considered with some detail in the next succeeding chapter. Strong winds blowing in a nearly uniform direction for several dfi^-s cause the waters of lakes to move with them, and to rise on the shores against which they are driven, so as frequently to produce disastrous inundations. A gale blowing from the north over Lake Michigan has been observed to cause a rise of seven feet at Chicago. Li Novem- ber, 1892, a storm from the west caused the waters of Lake F^vW, near Toledo, to fall between eight and nine feet below the normal fair % weatlier level. At the same time, unusually high water was experienced at the east end of the lake. The differences in the level of the waters of Lake Erie, at liuffalo, between a high-water stage produced by an east- ward blowing gale, and a low- water stage accompanying a westward or off-shore gale, has been observed to amount to 15i^ feet. An eastward movement of the waters of Lake Superior has been known to accom- pany a gale from the west and to produce an unusual rise in the watrr S of St. Mary's river. The height to which the waters reach on hike shores, owing to stroiii: winds, establishes the upper limit of wave-action, and leads to the forma- tion of storm beaches at an elevation of several feet above the normal ii'* ides with itablislit-'il ith return lakes lie he return the case a general 3 not been jaurentian in certain )r from BU rht if any V the shore lely to the ;he general •rents, with luce impor- ,llow. The considered everal days the shores disastrous ichigau has In Novem- Lake Erie normal fair experienced le waters (»f by an east- = westward ov Vn eastwanl u to accoin- iii the water iicT to stroiii,' to the forniii- L> the norm;il CO CO en LU en cc o lii 1 1 mv wji HI iii bitir ii'Ji I IP, ill I, II I -->.7S° 7.78° 7.0(1° 7.7-J° li.!l4° l).(i7° (>.n° 5° 40 )f the water lu'tevs). ami t»t have t they taiices of the rs, hut ley are •nished us and ;ver, as urrents ■iiihauk- so as to u the laniiel id and A case Huron, ions on The it woidd elta has a short forming earn, and action of mtlet.i •orkl are no hikes icthH- papt'i Mechanical sediments. — The coarse sedirnent hrought to hikes by streams is either built into deltas or swept along the coast by shore cur- rents and mingled with the })el)bles and sand derived from the wear of tlie land by shore waves. The liner products of the wash of the land, and of shore erosion, are carrieil lakeward and deposited in stratitied lay- ers over the lake bottom. In general, the slieet of material thus sjnead out is thickest and coarsest near sliore and Ijecomes finer and thinner as the distance from land increases. When sedimentation goes on uninterrui)t- edly until a basin is filled, the result is a more or less regidar lens-shaped body t)f sediments, having a broad central area of fine material, which graduates into a fringe of coarser character about its borders. The coarse strata in the shore deposits overlap and dovetail along their lakeward margins, with the outer l)orders of the layers of tine sediment in the cen- tral i)art f)f the basin, for the reason that the coarser material is carried farther from land during storms than when the weather is i-alm. This general relation of coarse shore and fine off-shore dei)Osits is of interest, especially in the study of extinct lakes, and may enable one to draw their former boundaries with considerable accuracy even when all distinctive features of their shore topography have been obliterated. The sediments of the existing lakes of America, so far as they have l)een studied, are princi[)ally clays, which vary in character according to (he nature of the rocks and soils on the neighboring land. The sediments of the Lattrentian lakes and of lakes generally, particularly in humid regions, are characteristically blue clays. The Pleistocene clays of the Erie and Ontario Ijasins are tenacious l)lue days, simdar to those now accumulating in the same basins; but the clays de[)Osited during a former Ijroad extension of Lake Superior are fine, evenly laminated j)iids- isli clays, and owe their distinctive tint to the color of tlie rocks from which the}' were derived. The sediments now accunuilati:.g in the lakes of the arid regions, l)ut more especially in the temporary or [)laya lakes, are usually light- colored, and have a yellowisli tint when dry. In regions of deep rock decay, like the southern Appalachians, the ,e: suf^FAcc: ,.-'' ^^^ lowing section of a rocky shore, which also shows the relation of the sea cliff h c to the platform or terrace ac at its base. Waves are only abb; to reach the land in a narrow vertical interval, determined mainly bv the dirt'erence in their heiuht durini'' calm weather and when storms are raging. Even in the case of large lakes this inter- val does not exceed ten or iifteen feet, and on account of the debris usually encumbering the shore, the actual zone of erosion on the fresh rock surface is normally very much less than this. The waves thus act like a horizontal saw cuttino- into the lan 3 O 5 CO >" ^ -z ^ 3 03 Ikflect eu w il TMK TOl'OUUAI'IIY OF LAKK SIlnUKS. 47 into (k'cp water and thus lose their power to truiis|»orl. The variiitioiis 111 tlie Hhapes of eiuhiiiikiiu'nt.s Iiiive led to tlie retuiriiitioii of various inore or U'ss s|)eeili(! forms, sueh as sjuts, U>ops, liars, \'-hars, etc., some of wiiicli are descriiu'd In-low. The liuihhiijr of eiiiliaiikiiH'iits «iiii he best sludifd where tlieri' is an iihrupt ehaii^'e in tlie (hivitioii oi the sliore adjaceut In a locality where the formation of a sea elitf and its aeeonipanyini; leri-aee is in progress. Such an instance is illustrated in the following sketch-map : Fio. 4. — Skkt(Ii-mai> ok ax Kmhaxkmknt. The shore on the right of the cove i.s steep and forms a sea cliff that rises ahove a terrace along which the current travels in the dii'cetion indicated liy an arrow. Shore currents follow the liidadei' outlines of the laml. hut (lit across jjays and inlets. For this ivason, in the case hefoie us, the sand and gravel swept ah)ng the suiface of the terrace is carried into deep watei-s and is dejiosited when the direction of the shore changes ahruptly, as the How of the water is then checked. The terrace is pro- longed as an emljankment, having the same level, and is lengthened hy material carried ah)ng its surface and deposited at its distal extremity, i'he construction of such an endianknient is analogous to the mannei' ill which railroad endiankments are made hy carting dirt along them fiom a cut and dumjiing it at the end of the unfinished structure, in cross sections an endjankment .shows a more or less perfect arcrhing of the material, and fornnng v/hat may he termed an "anticlinal of deposition." In the ideal illustration here presented, it is evident that a continu- ation of the i)rocess would result in the i)rolongation of the endjankment until it touched the shore at the left of the hay. The outline of the lake would then he simpliiied and a lagoon formed behind the cndiankment. Should a stream enter such a lagoon, the water escaping from it might keep a channel ojien to the lake, but a struggle would ensue hetween the shore currents tending to close the hreak and the outflowing water striving to keep it oj)en. Eddies in the conflicting I'urrents would result and lead to changes in the outlines of the embankment. fw il if . ir ;i Ifr if. iIHE' 48 LAKES OF NOllTH AMERICA. If ■! ^1 J ■:''! m When a structure like that (lescril)e(l above is incom})lete and projects l"om the sho'-e like an xmtinished raih'oad embankment, it is teimed a sjoiV. An iUustration of such an inst iice observed on the shore of Au Train island, Lake Superior, is shown in Plate 11. See also Plates 2, 3 and 4. When an embankment spans the entrance of a bay so as to shut it off more or less com])letely from the main water body, it is termed a bar, in accord- ance with the custom f)f mariners in designating such obstructions to navi- gation. Maps of bars on the shores of lakes Su- perior and Ontario are re- produced in Figs. 5 and 6, from the maps of the U. S. Lake Survey. The manner in which these were formed, as well as their various modifications ViV.. 5. -MA.. .,F HA.NI. HAK.S: WICST KSU OK LAKK SLLEUIOH. ^^^ ^^^^^-^^^ ^^^^^ .J^^ preSCUCe of channels across them in certain instances, will be understood from the description of a more simple example just given. The end of a spit is frequently turned toward the shore, owing to a deflection of the current that Ijuilt it, or to the opi)osing action of two or more currents, and becomes a hook, as is illustrated on Plate 12. Again, where the hook is more pronounced and the distal end of the structure touches the shore, as happens oci-asionally Avhen there are only slight changes in the direction of the coast line, a loop-bar or V-bar results. In. brief, it may be said that the waves and currents of lakes have the power of excavating cut terraces along the shores confining them and of carrying away the waste from the cutting, together with similar mate- rial contributed by streams, and of building it into terraces and embank- ments of various forms adjacent to neighboring shores. l>eltiiH.— Where streams lu'ing to r. lake more detritus than is carried away by shore current.-5, accumulation takes place and an addition, termed ili|ji!i!]|!i|piiliiijl!!!li!ifli!mn|iii]i™^ ig to a it' two do 1-2. of tlie only results. s liavf m antl ■ mato- inbauk- carrietl tonnetl cc q cc ill a. CO u < Q Z < _J CO < cc \- < HI -J a. (O ■TPT S if- iki i jl - I 1 iC L kil . THK TOPOGRAPHY OF LAKIC SHOPwES. 40 a delta, is made to the land. The most instructive deposits of this nature occur where high grade, streams enter a lake, as when a lake washes the base of a mountain range. In such an instance, pebbles and water-worn ])oulders are swept along by the stream until it mingles with the quiet lake water, where its velocity is checked and the coarser portion of its '^ ^ . — . ~y~^ — --I ' V..i,._ S7 ' Flu. G —Mai- of sand bars: soi'th siioke OP Lake Ontario. load dropped ; fine sand is carried beyond and deposited about the outer margin of the accumulation of l)oulders and pebbles, and the finer niaterial held in suspension is transported still fartlier fiom shoic and dis- tributed over the lake bottom. Tlie, coarse material is deposited alM)ut the moutli of tlie stream in a semi-circular i)ile, the 1)ase of wliicli is l)cneath the water and the apex t-'.mw distance al)ove, wlicre the stream iK'gins to lose velocity. The j)iU' is l)uilt out in all directions in which tlie water has freedom to flow, and a s<'mi-circular or ocjcasionally a truly delta-shaped addition is made to the land. Fine examples of deltas, Imilt by swift stieams adjacent to a precii)i- lous shore, occur on the west side of Seneca lake, New York, near Wat- kins. In these deltas the action of shore currents fn,m both tlie north and south is conspicuous, and the deposits have l>een cut away so as to leave a triangular or markedly delta-shaped outline, but the apex of each " delta " points lakeward, instead of toward the shore as is the normal jiyM i iuM W Mi i iiini i Bn aii 60 LAKKS OF NOJITH AiMEKICA. condition. About the niarjrins of these deltas there are sniall gran4' ^0j^ that are fre(iuently h)0[)ed and enclose la' streams and the shoi-' cu/i'<'ntx. which has niodilied the form of the deltas in the peculiar way yt*t referred to. ^V delta advances as fresh material is added to itK outer marjjfin, swi/J at the same time the apex of the pile rises and slowly migrates up stream. Such a dejtosit has a well-delined structure, due to its mode of giowth. A radial section made from its apex to any point nn its jx-riphery would show three divisions, as is indicated in the following sketch section of a delta built in Lake lionneville, at Logan, Utah. Fig. 7. — Section of a Delta. The history to be read in such a section is this : the fine, evenly strati- fied beds beneath the coarse inclined layers are sediments deposited on the lake bottom, but about the margins of deltas they are usually thicker than on neighboring lakeward areas, owing to more rapid depositions from the watei's of the delta-forming stream. In some instances a broad, low api'on-like deposit of fine sediment is formed about the lakeward margin of the delta proper. As the coarser portion of a delta increases, it advances lake\,-ard and covers the layers of tine sediment previously laid down, and fre(piently causes them to become folded and wrinkled and occaHionally broken and faulted, on account of the weight of material imj)Osed u[)on them. The l)oul(lers, gravel and sand brought down by a stream are carried to the outer nuargiu of its (-elta. and roll and slide down its siUnnerged lakeward slo')c so as to fornr inclined layers. The angle of inclination of ti!e.■^< layers is the angle of stability in water of the material fofmioi: them. Where the deposit is n.Kunly of rounded stone and gravel, the angle of slope is in the neighborhood of 30 to 35 degrees, but in souh instances is steeper and the structures are unstable and '"-'-.. rabl^^ foi landslides. The triangular area shown in the seetiou. alKive the inoiirj d beiis. the .subaiii'ial [»o;tiun (if the dtdta. built by the >'rean\ o. »» -ini i ru.^. ,-i,^l^ i..J4La.i)^ .iL^ " ■< k-i^^M-' I' Mrs JIM' f), »ttfi I roam. lOWtll. m of ii y strati- sited on thicker osilions V hroad. iii formiiii: ,^el. th.' In StHlH- I) Op; fol '.)>'0s. ■ i( i ili'--. t!J O ill OQ Ui cc UJ en C3 iO UJ > Q UI m ( s \' n i( ^\ t.-] tl sL ei fn ta (le ah fi-e m noi isl hor alx) and SJio lie the cf)m stru c'ati( basi] ] istic ice. nient taket THE TOPOGRAl'HY OF LAKE SHORES. 51 over its surface. It is really an alluvial cone, similar to the conical piles of debris so conunoii in uesert valleys at the mouths of high grade cartons. It is irregularly stratified, tlie layers being inclined at a low angle corre- sponding with the slope of thy surface of the structure at the time tliey were laid down. The change from the gently sloping and irregularly bedded material of the alluvial portion or cap of the delta, to the steeply inclined and more regularly bedded layei-s, marks the level of the lake in which the dei)Osit was formed. The outer margin or periphery of the delta, is in a horizon- tal plane and retains the same position as the delta .idvances, providing there is [)ractically no cliange in the level of the lake surface. Tlie surface slope of the cap of the delta, along radial lines from the ai)ex to the peri[)h- ery, is gently concave to the sky. On recent examples the surface is frequently scored with radiating and branching channels, or "distribn- taries," left by the changeable stream that built the structure. As a delta increases in size its apex rises and slowly migrates up stream, as already stated, so that in large deltas of liigh-gra^le streams the apex is frequently well within the mouth of the canon through wliich the draiiv age is delivered. In the deltas of low-grade streams, like the Mississippi, the divisions noted above are not readily distinguishati>le, as the material forming tiiem is fine throughout and the inclination of all the layei-s [» gentle. Should the surface of a lake be lowered after having stood at a definite horizon for a long period, the terraces, end)anikments, deltas, etc.. formed about its borders become conspicuous featui-»-s of the expoi*ed land surtace and another series of similar forms is at onee begun at a lower lev**!. Should another subsidence follow, another series of horizontal lint^ will be added to the topography of the shores. A rise of a lake -akuses the submergence of previously formed shore features, and they may l>e- come covered with fine sediment or have other wave and current-built structures imposed upon them. Such changes If^d to puzzling compli- cations in the records, as has been observed in many instances where lake basins have been emptied and their sides and bottoms laid Imre. Ice-biiilt walls. — In addition to the topographic features character- istic of lake shores thus far noticed, there are others due to the action of ice. In northern latitudes the formation of sea cliffs, terraces, embank- ments, et(;.. about the margins of lakes, excepting those of large size, takes place mainly in the summer season. In winter, when most small 52 LAICKS OF NOUTII AMKllICA. lakes arc Iid/cii over, tlic cxpaiisiini ol tlif icr |»iislit!s ii|) stones and fjcravcl aliiiin' slidvinn' sliorcs and t'Dnns otlicr t(»j)niri'a|iliic features. Anntlici' process lending' in part in tiic siinic direction conies into play in tlic spring' wlicn llie ice on a lake Ijceonies l)rokeii and is moved hy the wind. The action under these condilioiis is the same tiiat takes place on a nuich larn'cr scah- on tlic shoics of Lal)rapogra[)hy of lake shores, from which the following is quoted : — "The ice on the siiifaci- of a lake exi)ands while forming so as to crowd its edge against the shore. A farther lowering of tem[)erature produces contraction, and this ordinarily icsults in the opening of ver- tical fissures. These admit the water from below and by the freezing of that water arc filled, so that wlien expansion follows a Hulweijuejit jisfc of temperature the ice cannot assume its original position. It conse- quently increases its total area and exerts a sectond thrust upon the shore. VN'lien the shore is abrupt the ice itself yields, either by crushing at the margin t)r by the formation of anticlinals (upward folds) elsewhere ; but if tile shore is gently shelving, the margin of the ice is forced up the declivity and carries witli it any boulders or other hxjse material about which it may have fr(»zen. A second lowering of temperature (h)es not withdraw the protruded ice margin, but initiates other cracks and leads to a repetition of t4ie shoreward thrust. The j)roc,ess is re])eated from time t(j time during the winter, but ceases with the melting of the ice in the spring. The iic formed the ensuing winter extends only to the water 1 Geol. and N:ii. Hist. Surv..()f Cftnacla. Ann. H0-!)1, p. 04 H. * Anini<'iin Naturalist, vol. 2, IStil*. ])i). 1 |fi~14'.). 8 Fit'lh Ann. KHp., V. S. (it-ol. Surv., p. Kli). Vl'l- L list' ollSf- liore. tl le ; hut |» thf lllKlUt ■i not It'iids t'ldin lice in Iwater o LU 03 O UJ cc O X CO TIIK Torui.KAl'KV VV LAKK SHOltES. r)3 margin, and by the winter's oscillation of tenipenitnre can be thrust hmd- wanl only to a ci-rtain distance, determined by the size of the hike and tlic local cliiiiiitc. There i thus for ich locality a definite limit l)eyon(l wliich tlic pinjei'tion of lioulders cannot be ciuried, so that all are de- l)osited ah)nj^ a conunon line wliere they constitute a rid^'c or wall." Shore walls are not cons[)icuous al)out the margin of large lakes for the reason that tliey .eldoni freeze over and also because the winter's ice work is usually obliterated by the more active waves and currents at other seasons. They are not formed about deep lakes for the reason that such water bodies do not become ice-covered, and for the same reason they do not occur in warm climates. In this brief sketch (»f the topography of lake shores, an attempt has been made to direct .attention to the main processes by which the results liave been reached, and to describe biiefly the character of some of the more striking forms produced, without attempting an exhaustive analyMs of the subject. To the reader who would go farther in the studies here outlined, I most heartily recommend (i. K. Gilbert's attractive j)aper on the topograi)hy of lake shore, in the .5th Annual Re[)ort of the U. S. Geo logical Survey, and the more special volume by the same author on Lake Bonneville, forming Monograph Mo. 1 of tlie publications of the U. S. Geological Survey. <^ IMAGE EVALUATION TEST TARGET (MT-3) /. ^ V. f/. ■«!; t 1.0 I.I 1^12.8 2.5 22 M 18 Ul ill U 116 V] is still f>'reater, (>r when the area from which a hd44 part per thotisand t»f total solids in solution, of which 0.0oroximately correct as they depend in most instances on a single analysis and on a small iuiml)er of nieasure- nu'uts of volume. The invisible loads carried by rivers are not only of interest in con- ne'tion with the study of lakes, more esi)ecially of saline lakes, but oi»en a wide lield of research in reference to the chemical deiuidation of the land, the comi)osition of ocean waters, and the source of the material, more particularly of the calcium car])onate. secreted by marine plants and animals. Into tiiis 1)roadcr domain, however, to which our subject leads, we may not now enter. 1 The (lata from wliic'i tlii' fitcts licit' stated were ol)taiuecl, as well as similar infovmation concerning otluT streams, i.s yiveu in Monograph No. 11, I'. 8. (ieol. Snrv., ])[\. 172-17'). liELATlON OF LAKKS TO CLIMATIC CONDITIONS. 57 Types of Fuksh liAKEs. Of the tens of tliousautls of fresli hikes scattered over North Ameriea, and esiiccially abunihint in the iirevionsly trhieiated, nortlieasterii i)or- tion of the continent, or forniin<>- a jiart of tlie more impressive scenerv of the Cordilleian rej^ion, many mi<;ht he seh'cted as types. Atten- tion will lie conlined, liowever, to the (ireat Lakes, drained l)y the St. Lawience, Lake Tahoe, California, and Lake Chelan in the State of Washington. Tlio LainviitiiMi lakos. — The gronp of great lakes drained by the St. Lawrence, as is well known, contain the most maoiiificent examples of fresh water-bodies now existing on the earth. Lake Snperior still ifiains its position as the largest slieet of fresh water known, althongh tlie moi'e recent discovery of Lake \'ictoria Nyanza has bronght a lival into the field. This African lake is estimated to have an area of about 18,000 s(|iiare miles, which is 1:^.000 s(piare miles less than the area of the great American lake; but when an actual survey slir.ll liave been nuuh'. it is ]iossi])le that this difference will be materially decreased. While Lake Superior exceeds all other fresh lakes in extent, it raidvs second among terrestrial Avater-bodles, for the reason that the Caspian Sea is the largest sheet of water not in open communication with the ocean, now existing. The Caspian is saline, liowever, and falls in the second irreat division of lakes here recofjni'/ed. The orii^in of the basins of the Laurentian lakes has been referred to in Chapter L in connection with the action of glacial agencies in obstruct- in.g drainage; an account of their i)ast history is given in advance ii' dis- cussing the I'leistocene lakes of the same region ; at present atteni'ou will be confined to some of the more interesting features of the existing lakes. The U. S. Lake Survey. — A survey of the Laurentian lakes was made by the Corps of Engineei's. C S. Army, l)etween 1841 and 18M1, and is known as the l'. S. Lake Survey.' On the maps or chart published l)y that survey, the outlines of the shores of the lakes and of their con- necting Avatei-s are given, together with the tt)pography of a narrow strip of the adjacent land; the de[)th of water, character of bottom, etc., as ' Ht'ljovt upmi the rriiiiary 'rriiuiguhuiun of the U. S. Lake Survey, by Lieut.-Col. C. B Comstock, Washinjrti'n, lS8'i. w 68 LAKKS (»!•■ N(>I;TM AMKIMCA. 2.t50 .•J7,700 G(M50 Lake Uiiroii ami ';e()rt;iaii liay 2:5,800 :n,7oo 55,500 St. flair river 25 ;5,800 ;}.825 Lake St. Clair 410 3,400 ;5,810 Detroit river 25 1,200 1,225 Lake Erie f).()fiO 22,700 ;32,(i(i(t Niagara ri\('r 15 ;500 ;5i5 Lake Ontario Total 7,240 21.()00 28,840 !).'),275 174,800 270,075 The volume of water tiowing through the rivers draining the various lakes is on an average as follows: St. ]\Iary"s river, the outlet of Lake Superior St. Clair river, the outlet of Lakes Huron and Michigan Niagara ri\er. the outlet of Lake Erie St. Lawrence viver, tlie outlet of Lake Ontario . , Crnic Fkkt I'KR SKCONI). 8(i,000 2:55,000 2(15.000 ;5oo,ooo 1 "Physical Features of the Northern and Xorthwesteru Lakes," Amer. .Four. Sci., M sec, vol. :W, 1887, pp. 278-284. |l 1 UKLATION OK LAKKS TO CIJ.MATIC CONUITIONS. 59 Tlie mean elevation of tlic sinfiiccs of tlic ryauveiitiaii lakes above the sea, their maxiinum depth, etc., as shown by soundiiii^s, are as follows : Mkan Kr.r.vMiox and .Maximi m Dkj'tii. ktc. ok thk Laikkntian Lakks. .150 ,5(10 ,82.') 810 2,(t(iO Ji.") 8,8-10 r(),07o various UK- Fkf.t ;k Sk<:<>nI'. SCi.OOO :!."),()()() '(i.'),(tOO 00,000 •. Sci., 3(1 JlKAN Klkva- rio.v. Ai'i'imxiMATi': AlKAN 1»E1'TH. . Ma. MM CM ln:irii. DrpTii UK 15AMIN Mll.DW Ska Lkvkl. Lakf Erie f.jikc Unroll .... I-iiki' Miclii,i;an . . Lake Ontario .... Lake Suiierior .... .")81 r)8i 217 002 70 2r)0 'M)i) -17.-) 210 7:50 870 738 1,008 140 2H0 1!M KM) The average disehai-ge of tlie lakes is stated by Schermerhorn to be double that of the Ohio and nearly ecjual to one half the dis('haiy ill! iuiiilysis of tlie water ot" St. Liiwrciicc river tiikeii neai' Mdiitreal. 'I'liis analysis may also be eoiisidered as represent int.'; very nearly tlie ei»in- jiosition of the materia, arried in solution hy the lakes iiud rivers of the more humid ixntions of Nir.th Americii.' A.\Ai.vM> t»i' TiiK Watiu oi St. I>a\vi!i;.\< k Hivku. liY T. .Stkhuy llr.\T.'- lNIKXTS. I'AHTH IX A TllorSANIl. Sodium, Nil l*(>tas,siimi, K C'aleiuiii, Cii Miiiiiicsiimi. AIj;' Chlorin.-. CI Cailiiiiiic a(;ih is known in a (|nalitative way, how- ever, to show that important changes in the outlines of these lakes are in proj^ress. The waste of the shore, resultinn' in a hroaih'ninjr of the sur- faces of the lakes, is comi)ensated in part hy the deposition of tiie material removed on adjacent area so as to I'Xtend the land lakcward. as. for exaujple, at the south end of Lah^ Michigan, where heaches and larjj^e sand dunes have been formed, and are still encroachinn in tlu' near future. The lisheries of the Laurentian lakes is another suhject of great prac- tical importance, as they are the most extensive lake lisheries in the world. The lakes ahound in trout, whiteiish. and otiier food iislies, and their shores are dotted with lishiuM vilhii^fes. in which a hardy poi)ulation. skilled in all that pertains to their calling, are 'iving tlii'ir hunihle hut useful lives, and gaining an ex])erient^e which well tits them for naval service should their aid hii called for. The impor'anee of these inland lisheries has received tardy recognition in comparison with the similar industries of the sea horder, hut they are a suhstautial elemjent of national wealth and claim the most careful attention and guidance of hoth state and mitioual legislators. The reports of the U. S. l"'ish C'ommission 'h. w that over ten thousand persons ai'e engaged in this industry : that the capital invested is in excess of four and one-half millions of dollars : and that a hundred million ])ounds of fish are secured each year, which hring to those actually engaged in the work more than two and one-half millions of dollars. It may he noted as an item of interest in connection with the ])hysical history of the Laurentian hasin, that in lakes Superior and jMichigan crus- taceans and tishes have heen found that are helieved to he identical with living marine forms. These are thought hy some persons to indicate that the lakes in which they occur were formerly in open connnunication with the ocean. Considerahle evidence, derived from a study of the foi-mer extent of the lakes, and of the fossils in the sediments of previous water-hodies in the same basins, do not seem to confirm this conclusion, however, and further study of the habits and means of migratioix of the species referred to, is necessary before their presence in inland waters can be satisfactorily accounted for. The movements of the waters of the Laurentian lakes and a few facts respecting their temperature and their ii'fluence on the climate of the itKLATIoN <»!• I.AKKS !'( ) (LIMA lie (.'OMUTIO.N.S. 68 ai>t'd that they may s()(»n icccivc the attention in this (hrt'ctiun tiit'V so well deserve!. >loiiiitaiii lak<'H. No account of the lal^es of North AnuM'ica is i on hrevioiis j)U'te tiiat (h)t's not inehiih- some notice of llie thousands of hasins amid the nortliern A]>i)ahiehians, and in tlie ('(/rdilh-ras, in wliieli the most luaniiiticent seeiierv »>f this continent is n lleet t'(l '11 ii'se awes are .f all sizes, from mere tarns across which one; miyht spring with the aid of an alpenstock, to broad plains of blue, many s(piare miles in area, and worthy of comparison with the most ix-autifnl mountain lakes of othei' lands. Of this aUraetive class of lakes special attention can only lie ^iven at present ti» two examjiles which are deslined to he widely known on account of their many charms. I rider to Lake Tahoe, i'ndiosome(l am(>n<^- the peaks of the Sierra Nevada, and lyin^' partially in Califoi-ina and partially in Nevada.; and to a lakt; of a different ehaiacti'r Init not less maniiilicent, situated in the ("asiiule inouiituins, in the Statu of Washingtoii, and known as Lake Chelan. IaiUv TaiKH'. — This " L^i'm of the Sierra" is situated at an elevation of t)200 feet above the sea and is enclosed in all directions by I'lj^ruc.,!^ forest-covered mountain slopes which rise from two to ine(L Near shore, where the bottom is of white sand, the waters have an emerald tint, but are so clear tliat objects far bem-ath the surface may be leadily distinouished. Farther lakeward, the tints ehanj^e by insensil»h' , iiiclics in (liiiint'tcr, when t'astcncd to a lint! and lowcrt'd hcncatli tin- snrt'ucc. \\i;s clearly visihU^ at a (K'litli ol' lOH feet. It is to In- rfinenihcrcd tli^t tlic li,i,'lit reaching tlie eye in siicli an exptM'iinent tiaverses tlironj^li water twice the disinnee to wliidi llic disc is sid)niereiiment refeired to, lilti feet. The miK instanci' in this conntry in which wati-rs have heen '"onnd to he more tiansparent is in tno f,'i(!at liniestone-water springs of I"'loiida. Soundinfifs made in Lake Tahoe i)y I.eConte, as idrciidy stated. r of Chelan, an Indian chief of consideral)le local renown, -vhose villagt! stands on its .shore, empties into the Columbia through a deoj) tortuous gorge of recent origin and sends a swift stream of clear, greenish-tinted water alxnit two mih'slong, to join the great river in the adjacent canon. The lake is a narrow, river-like sheet of water, with gentle windings, extending westward from the Columbia, seventy miles into the mountains, and is bordered on either hand by a continiU)Us series of rugged peaks that rise from live to over seven tliousand feet above its suiface. The deep, narrow, treneh-like valley, now partially 1 For analyses of the waters of these lakes, see p. 72. m LAKKS OF NOItTH A.MKIMCA. ! 1 1.* ^ water-filled, cnntiniie.s beyond the lic;iil of tlu' lake for a distance of at least twenty-live miles, becoming,' nioic anil more wild and rnj^-^'ed as it nears the heart of the hiijfhlands. 'IMie total lenjjth of this remarkable valley is not less than one hnndi'cd miles, and its width at the level of the lake seldom exceeds four miles. . The sonndinin- line has shown that Lake Chelan is over eleven hundred feet deej), but its full (U'pth remains to be determined. In several sornd- ings madi! by the wi'iter in its central and westeiii })ortio!is, no bottom was reached at the de[)th indicated. The siirfi'ce of the lake is but dij'.j feet above the sea, so that the bottom of the trough is below sea level. Where the clear water of the hike washes the jjrecipitous walls enclos- iuff "t there is no beach, and scarcely a trace on the rocks to show that it has altered the topograi)hy of the shores. The present conditi(»ns were initiated at such a recent tiate that, practically, the only changes they have }»ro(bxced are at tlie eastern end of the lake, where it emcrgi's from the rocky detile of the moinitains and for a short s[)ace expands between com- paratively low shores of gravel and sand. In this region high terraces mark the former level of the water surface. How the great gash in the mountain, fully one hundred miles long, and now filled for more than a thousand feet in de[)tli by the lake, was f.»rmed, is n()t easy to explain. Previous to the birth of the i)resent lake the valley was occupied by a large ghu-ier which flowed through it and joined another great ice stream in the canon of the ''olnnil)ia. The ice smoothed the precipices of rock and [)iled up moraines on the moie gentle slopes at the east end of i!ie valley, but that the main depression existed before the glacial invasion is evident and is in harmony with the histories of many other valleys in the Cordillerai. region. The valley has a still mtne ancient history, and in Tertiary, or in part perhaps in pre-Tertiary times, was excavated in the hard granite, now seen in its enclosing walls, by the slow wear of streams. It is a stream-cut channel, but where the stream rose that did the wcu'k, or whence it Uowed, remains to be deter- mined by a careful study of all the facits bearing cai the problem. It has been the writer's fo'-tune to pitch his cam[) on the borders of both Lake Talioe and Lake Chelan. As the scenery of each is conjured up in revery, it is diflicult to decide which is the more remarkable or which shouhl have the first rant among the mountain lakes of America. Each lake is surrounded by fore.-it-covered UKnintains of mi'jestic proportions and rich and varied details ; the waters <»f each lake are lear and deep in coh)r, or varied by silvery reflections and iridescent tints where the not RELATION or LAKKS TO CLIMATIC ("ONIHTIONS. 07 o-entU' of both (i nji ill r wliicli Eiu'li l)ovtions deep ill 1 the Hot too gentle mountain winds touch their surfaces ; in each instance the scene is fresh and niiiuiint'd. and has the charm of remoteness so welcome to many wlio are weary with the ways of men. At Tiilioe the views are wide and far-reacliing. The shaofgy moun- tains are jjicturesquely groui)ed about the (central plain of waters and the scene is open and, for a mountain stroufjhold. mild and pleasing. At. Lak(; Chelan the scenery is wild and rugged. Tlie narrow stream- like she<^t of water, witli gently curving shores, extends far into tlie mountains and cannot be conqnehended at a glance. Each view, as one ascends the lake, gives suggestions of something still more grand beyond. Eacli turn reveals hic'den beauti"s that entice one on and on. The bordering moiiutain.s become more and more rugged, as we venture farth'U into tlieir embrace. Eacli newly discovered peak is higher and more imposing tliiin its predecessor ; until at the head of tlie lake, the most lofty summits of the range, usually white with snow, can l)e seen far' up the gorge l)eyon(l wdiere boats can go. The narrow valley bottom beyond the lake is filled with majestic trees and a rich profusion of lower vegetation of almost tro[)ical density ; tlie dark vine-entangled forest seems striving to conceal some mysterious shrine farther within the lieart of the mountains. A clear, swift stream tlov/s silently beneath the deep shade of the broad-leaved sycamores; and from far witliin the hidden recesses of the valley, the echoes of unseen cataracts i-ome faintly to the ear. What wonders exist in the U])[)er portion itf tlie valley are not known, as they have been seen by o.dy a few white men and liave never been descrilied. All of the surroundings of this wondcful lake are so fresh and speak so strongly of the untamed beauties of Nature in lier wildest moods, that a visit to the region has the zest aiid fascination of entering an uiuHs- covered country, where each ste[) takes one farther and farther into the unknown. T'he vegetation of the Cascade mountains is fir moie luxuriant and varied than the flora of the Sienv Nevada. \n every nook and corner one is sni'iirised and charmed with the rank luxuriance of tlie gracefully liending ferns, or the jirofusion ami brilliancy of the flowers. On the higher slopes, between the forests and the Imre summits of the cloud- capped [leaks, the angles of the rock are softened by luxurianv mosses and lichens, and the gray of the cold granite is brightened by Alpine blossom). Tent life on the shore of either Lake Tahoe or Lake Chelan is delight- ful. Each lake has its own }jeculiar cdiarms, but their influences on the £* !? • f i -, 1 Ml II ■■;i V 68 LAKKS OF NORTH AMKUICA. mind are different. One <>:• the otlier will be declared tlie mmc attractive according to the temperaimnt of the person who yields liiniself to their influences. Each is poetic, and will weave a web of golden fancies in the mind of its admirer, ^vhicll will be as nectar to his thoughts when his feet tread other and less insi)iring })atlis. Owinjjf to th4 verv moderate elevation of Lake Chelan, its climate is mild throughout almost the entire ye.a', and is deliglitful fr;les of the mountain lakes of America have beeu referred to, for the reason that the sjjace at commrnd does not permit even the mention of the hundreds of charming examples, many of them of greater size and in their milder fashion as attractive as those of the Sierra Nevada and Cascade mountains, which add variety and beauty to tl e New England States, New York, etc. Extending our survey to Canada, a still 1 A more complete account of the region about Lake Chelan than can be given at this time, may be found in a report on the Upper Cohunbia River by Lieut. T. W. Symons ; ITtli Congress, Ist session. Senate Exeeutive Doe. No. 18(i, Wiisliington, 1882 ; and in a report by the .author, on a Geological lieconnoissanee in Central Washington, U. S. Geol. Surv., Bulletin No. 103. . ^ RELATION OF LAKES TO C'LLMATIC CONDITIONS. 09 greater host of inland water bodies of almost every variety imaginable, attract the attention and cause our pen to linger; but here again we can only say that tliey belong to a great class of which types have been briefly described. Salixk Lakes. . , i Saline lakes are formed principally in two ways. First, by the isola- tion of bodies of sea water, as 'vhere a rise of the land cuts off an arm of the ocean, or sand bars or coral reefs enclose lagoons. Second, by the concentration i)y evaporation of ordinary river waters in enclosed basins. Tlie lirst are of oceanic and the second of terrestrial origin. abun- intains, been ourists, assur- wishes of the ^e been lit even lem of Sierra e New , a still en at this )iis ; t7th rcpoi't by 1. Suiv., Saline lakes of oeeanie, <»riK'in. — There are no conspicuous exam- ples of this class of lakes in North America, although lagoons cut off from the ocean by sand bars do occur, especially along the southern Atlantic coast. A large lake of salt water that was isolated from the ocean by a rise of the intervening land formerly occui)ie(l the valley of Lake Cliamplain, but has been freshened and its surface lowered by overflow. Tlie type of saline lakes which were formerly arms of the ocean is furnished by the Caspian sea, the largest body of inland water known. The observations of many travelers have shrtwn that this sea has been divided from the ocean by the elevation of the intervening land. 'VV.e climate of southwestern Asia is arid, and over large areas evaporation is in excess of precipitation. For this reason the ('asj)ian has contracted its borders, in s[»ite of the large contiilmtion of water delivered to it l>y the W)lga and other streams. There is evidence in the chemical composition of tlie waters of ihe C'as[)ian, and in the topograi)hv of land separating it from the lUack sea, to indicate that at first it was freshened by overflow, as in the case of the ancient lake of Cliamplain valley, an i. tliat i'.s present salinity has resulted i)iincipally from the concentration of ri vcr wateis. It may be considered, therefore, of oceanic or of terrestrial o 'igin as one chooses. The Caspian is 180, OOO sipiare miles in area, or nearly six times the size of Lake Superior. Its maximum deiith is in the neigliborliood of ;].0()0 feet, and exceeds the dei»th of any other 'ake known. It is with- out outlet. Its waters contain (!.l2m ))arts in a tliousand of mineral mattiU' in solution, consisting prin('i[!ally of sodium chloride and mag- nesium suli)liate. The waters of the ocean, it will be remembered, coli- cs i^ 70 LAKES OF NORTH AMERICA. tain, on an average, 34.4 parts per tboa.sand, or, in round numbers, 3.5 per eent. One of the most instructive features connected with the Caspian is the manner in which it h)ses its saline constituents by discharging into a secondary basin, where tlie waters mv. still more highly 'joncentrated. On its eastern shore there is a deep bay or gulf known as Karabogaza, which is nearly shut oft" from the main water-l)ody by intervening sand bars, and receives its only influx through an opening in the l)ar about 140 yards broad and 5 feet deep. The water escapes from Karabogaza solely by evaporation, and is replaced by a current fi'om the Caspian which has been estimated by Von 'Baer to carry 350,000 tons of salin(! matter daily from the sea to the gulf. The waters of the gulf have reached the point of saturation for conunon salt, and precipitation is tak- ing place. These peculiar conditions are of great interesc, not oidy in .showing how deposits of salt may accumulate, Imt also in illustrating the manner in which an enclosed lake may deposit a large part of its foreign matter without the entire Avater-body becoming highly concen- trated. Saline lakes of terrestrial oriffiii. — The existence of lakes of this class depen 0| © o © . q . ?c r^ , , , q . . , • » ...,^ 1-^ t-H cc Walker Lake. Nevada. >0 4; ire ^ ire .^ A o o w ^H i*^ 1- -f .K ire ire irs i2 H ^1 X • vt • -t< — • • * 1^ • ■ ' • 1—1 ire CI c q ■ lO ■ -^ ci ire q ci • S ^ 0^ »— » .«. ,» CI cc cc •^ a< u £ ,- o T-H CI i-^i 1-H • ^ ire OS -iSsC lO ' CS q • iC • o cc " • • »-H • • Si * 1-H 5:3'^^ o • • ■n ' o: ■«*< • • ' * • to-* * X CI (f M,r-- C' cc ^.1^ o ire •n u U X -f ^ ^H o ^ ^v' ^ ^ -f ^ ^ ^ ^ , ^ ^ , 5 r 'jc •>! 00 l'^ ire cc •ii CC ci ' lO ■ * d ' ' ' * * * ' * d (M "f X s .-':' ^ ». c: 1^ ^" >.. 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JS « • - 1 30 © ; c •^ 5 C " ?^ 5 "o > >• X M t^ ; "o 3^ r Ol ^ r N .-4 — '/' :^ J^ t-^ ^ ^^ c ; ■^ -a : s s * <^ -s .U C4 M D &,*5 . e^ Ji S t»> a.^ "3 to OJ 01 — CO a^ r. ctf 5 c o -^ r< N li()ltliii<,' a imiuluT of suits in soliitiDU, when slowly cvaporiited, do not (lt'i>osit thuni in a lioino<,'tMU!()U.s mass, hut in sucuossive layers of varyiiii; (•oiii[)osition. As tlic order in wliieli ditl'erent salts an; dejjosited varies with the eoniiiosition of the waters, it is safe to say that in no two lakes is the snecH's-^ion ot" saline deposits formed on evaporation a[)t to he the same. l)isre<^ardin^ for the [)resent the reaction of the varions salts ii[»on each other, it ' evident that in the evaporation of natural waters the order in which the contained salts will he i)recipitated is inversely as the Older of their soluhility. I'^or exan'ple, a salt which re([uhes a l.irtfc amount of water for its solution, or, in other words, is sjiarinjj^ly soluide, will reach its point of saturation and commence to crystallize out as evaporation progresses, previous to the deposition of a more soluhle salt. To illustrate : it has hceu found that calcium carhonate reciuires ahout 10,000 times its weii,dit of water, saturated with carhon dioxide, for its solution ; while calcium chloride is deli(][ueseent, and dissolves in ahout its own weijfht of water. In an enclosed lake to which streams and springs are hringing these two salts in e(iual quantities, and in which evaporation equals or exceeds the supply of fresh water, it is evident that the calcium carhonate wouhl reach its [)()int of saturation and eoimnence to sei>arate long hefore the waters had hecome rich in calcium cldoride. In fact, owing to the deli(piescent nature of the cldoride, natural evapora- tion .seldom proceeds far enough to cause its precipitation. The early deposition of calcium carhonate, when natural waters are concentrated hy evaporation, is rendered the more certain for the reason that it is hy far the most almndant salt found in surfi.ce waters. The fact that various salts are deposited in a I'egular succession when mineral waters are evaporated, is of great service in separating certain ones in a jjure state hy the method known as fractional crystallization. In evaporating the hrines of Syracuse, New York, the [»reci[»itation of ferric oxide and of calcium sul[)hate, or gyi)sum, is first secured hy mod- erate concentration ; the hrine is then conducted to lower vat« and evapo- ration continued until the sodium chloride, or common salt, has mostly crystallized and fallen to the hottom ; the mother-li(pior, rich in magnesium and calcium, is then allowed to go to waste. A similar process frequently takes place in nature, but the salts precipitated collect in the same basin in alternating layei's. In the Soda lakes near Ragtown, Nevada, a double carhonate of sodium and calcium, known as the mineral gaylussite, forms on the bottom, owing to natural concentration. When the waters are still farther evaporated, 74 LAKKS OK NOUTH AMKItlC'A. Il{ 1 li'i sfxliiiin siilpliatf and sodium carlxtiirttf are jtrefipitated previous to tlio I'lvstallizatioii of cominoii salt. It lias ht'cu round on font'eiitrutinj,' sca-watci' that calcium carbonate is usually the first c(»nstitucnt to be jirccipitatcd. This salt is not always found when tlic waters of the ocean aic analyzed, hut may usually he detected in sam|»les taken near shore. The vast quantity delivered to the ocean hy rivers is soon eliminated hy jilants and animals and secreted in their tissues. The succession of chemical iirecipitates fnimcd in sea-water has heen described by M. Dieulahiit' as follows: " Fii-st ii very weak i)rc'cii)itation occurs of carbonati! of lime (calcium carbonate), with a trace of strontium, and of hy(bated ses(iuioxide of iron, miiif^led with a slight proportion of mant^anese. The water then con- tiinu's to evaporate, but remains perfectly limpid, without forming- any other deposit than the one I have mentioned, till it has lost 80 per cent of its oritjinal volume. It then bejifins to leave an abiuidant ])recipitate of perfectly crystallized sulphate of lime with two e(pii\alents of water or gypsum, identical in Lj'eometrical form and chemical con-position Avith that of the jfypsum-beds. This deposit continues until the water has lost 8 per cent more of its orit^iual volume ; then all }tiecii)itation ceases till 2 per cent more of the (uiyinal (puuitity of witter has evaporated away. Then a new deposit bej^ins, not of' gypsum, l)Ut of chloride of sodium, or sea salt. . . . The deposition of piu'e or conunercial salt con- tinues till the volume of the water has Ikmui atjain reduced by one-half, when a ijrecipitalion of sulphate of magnesium beifins to take i)lace Avith it. 'J'his continues, the two salts beinj,' de[)osited in eijual (piantities, till only 3 per cent of tlie orijj^inal (]uantity of water is left. Finally, Avhen the water has been concentrated to 2 j)er cent, carnallite, or the double chloride of jjotassium and mannesium, is deposited. Spontaneous evapo- ration cannot i,n) much further. The residual mother-water will not dry up at the ordinary tempv.ature, even in the hottest regions of the ylolu' ; its chief ccmstituent is chloride of magnesium. A body of sea-water evapcu'ated naturally Avill, then, leave a series of de})osits in Avhich Ave Avill find, as avc diq- down, the folloAving minerals in order: dclicpiescent salts, including chiefly chloride of magnesium ; carnallite, or double chlo- ride of potassium i'.nd magnesimn ; mixed salts, including chloride of sodium and sulphate of magnesia; sea-salt, mixed Avith sulphate of mag- nesia: pure sea-salt: ])Ui'e gypsum; Aveak deposits of carbomite of lime Avith sesquioxide of iion, etc." 1 ropular Science Moiitlily, October, 1802. i;i:lati<)N or i,aki:s to climatu; co.NDrnoNs. :5 us to the Oarbonatc at ahvay.s isni\lly 1m' livfii'cl to I sueieted • has Ik'cii e (calcium (h' of iron, tlu'M coii- riniii^' any 10 j)ci- cent •cipitate of il' water or sition ^vith water has tion ceases evaporated •hlt»ri(k' of il salt con- iV one-half. )»laee with ntitics, till lially. when the (louhle |nns cvaj)!)- ill not (h'v the g-h)he : st'a-water which we litjueseent oul)le chlo- ;hh)ridc of Ite of mag- te of lime Tn the natural evaporation of water in enclosed hasins the snceession will seldom l)e as icjrular as described ai)ovc. for the reason that the process is a|)t to he interrupte(l l)y the addition of fresh supplies of watei', and the suceessioM l)c;,fun anew, or else ehemieal chan«."'s initiate(l which will vary the results. In this coniu'ction it is to lie noted also that chan^'cs of tem- perature, as fi'om sumnu'i to winter, nmy modify the successictn of salts (leoosi ted. The sei)aration of sodium sulphate, potassium chloride, and common salt from the mother li(pU)r derived fnun the concentration of sea-water, liy alternate evaporation and coolin<;\ is the jirinciple (d" Halard's w(dl- known ])rocess largely used for ohtainintf salt from sea-watei' in the south of I'hudpc. In Mesel's niodilication of this }troct'ss, a low tempeiature is ol)taincd artilicially. When sea-water is concentrated until its specific gravity is 1.24 (28° of IJcaume's hydrometer) it deposits ai>out four-lift lis of the conunon salt it orij^inally coutaiui'd : after addinij Id per cent of sea-water to the mother litpior remainiuf;, it is passed thiouu'li a refri^'cr- atiu}^ machine and its temperature lowered t(» — 18" ('. The low tempera- ture causes double decom|)ositiou to take jtlace lu'twicn the magnesium sulpliate and the sodium chloride, sodium sulphate heinq- deposited and the magnesium chloride remaining in solution.' A process similar to that just (leseril)ed occvirs in nature, as is shown hy the precii)itation of large quantities of sodium sulpliate from the waters of Great Salt hdce, durinjr cold weather. This anticipation of llalai'd's ]»rocess is noticed in advance in connection with other features of (ireat Salt lake. The correspondence hetwecu the succession of salts formed hy the evaporation of sea-water, and the succession found in many saline dej)osits deeply buried in the earth's ciust, is of great intcicst and no doubt e\i)lains the genesis of souu' natural accunudatious of this character. It is not always necessary, Iiowcvit, iii seeking an expbmation of the oiigin of beds of common salt, gyj)sum, etc., fouiil;iiits us ii j)art ol" tlii-ir vitiil t'uiictioii. Iiiit tlu' process is not woll iimU'istood.' 'V\h' ori^jin of oiilitic siind, consist iiiLf of little spheres tonnud of coiietiitiie eo;its of eidciuiii ciirhoimte, iiloii^ the shores of (iicat Salt lake, has hoeii referred to an aiialoLfoiis proeess.- Coial-like ^'rowlhs (»f ealeaieoiis tufa in some of the stronj,'ly alkaline lakes of the (irout llasin are also thoiighl to owe ihuir origin to iho agency of low forms of phint life/* An important feature in this function of sulwupioous idunts, is that calcium carbonate may he [irecii)itated from waters that aru far below tho |)oint of saturation. In some instances precipitation is known to occur in this manner from water in which chemical ti'sts fail to rcvi-al moiv {\:m\ a trace of calcium. Feme oxide is not known to be an important dcjiosit in any of tho lakes of North America, although found in abundance in many swamps. Ill Sweden, however, its precipitation from the water of fresh lakes is so abundant that it is of conunercial value. The iron is carried into the lakes by streams, as Ji carbonate, and is [irecipilated on account of the loss of carbon (hoxide, in part at least, thidugh the agency of low forms of vegetative life. In some instances diatoms aie thought to play an im- portant part in secreting the iron. With this brief sketch of the manner in which i)reeii)itates may be foi'med in lakes, let us turn to actual eases where the process is in operation. Of the considerable number of saline lakes of North America that have been studied, two arc here selected as types. These are Great Salt lake, Utah, and Mono lake, California. Fortieth Parallel survey, in charge of Clarence King, in 1809, shows an area of 217<> si^uare miles ; the increase m I'J years l)eing 420 square miles, or 24 per cent. Its outlines when these surveys were made aiv shown in Plate 15. At its highest observed stage in 18G0, it had a maximum depth of 4'J feet, and an average depth of approximately 19 feet. In 1850, the maxi- mum de[)th was 30 feet, and the average .ibout 13 feet. Since 1875, careful records of the fluctuations of level liavc been made and Ijotli annual and secular changes noted. ^ The annual high-water stage occurs in June, and is due to the melting of the snow on the Wasatch and Uintah mountains. The fluctuations embracing a series of years have not been found to be regular in their periods and are not coincident with observed climatic changes. The sliores of Great Salt lake are h)w exce[)t where a mountain uplift j)rojects into it from the north, forming a rocky promontory, and for a sliort distance on its south shore where it touches the northern end (>f the Oijuirrh mountains. Its surface is broken by several islands of whicli two are short mountain ranges of tlie type so characteristic of the (in ;it Hasin. These rise more than a thousand feet above its surface and ;iiv rugged and precipitous. They stand like Nilometers in the salin.; .vaters. and on their sides are many horizontal lines marking former levels of the lake's surface. Tlie highest of these scorings is about 1000 feet above the present water surface. The scenery about this great lake of the Mormon land and in the encir- cling mountains is unusually fine, in spite of the aridity and the generally scant vegetation of the region. The sensation of great breadth that tlie lake insi)ires, together with the picturesque islands diversifying lbs sur- face, and the utter desolation of its shores, give it a hohl on the fancy, ami wakens one's sense of the artistically beautiful in a way tliat is unrivaleil ' The rcciinls (if tliesc clinnjit's up to IS'.tO. tou;etlit'r with ii (lisciissinii of tlieir .sijiiiiticanci' is .yivfu by G. K. CiilbiTt, in Muuo<;mpli Nu. 1, U. S. Geological Survi'j-. .> ''^X Lari:s of Xonrn AMKiiir.\. Pi.ATr; Vi. iBRfOHAM CITY CdREAT SALT LAKE, UTAH. (AFTER GILBERT,) rsiguitioiiucc m: ii. RELATION OF LAKES Tt- CLLMATIC CONDITIONS. 70 1))' any other lake of the Arid region. Tlie iinusuiilly clear air of Utah, especially after the winter rains, renders distant niountains remarkably shar[) and distinct, jjarticularly when the sun is low in the sky and a strong sidelight hiings the sharp serrate crests into bold relief and reveals a richness of sculpturing that was before unseen. At such time the colors on the broad deserts, and amid the pur[)l(! hills and mountains, are more wonderful than artists have ever jtainted, and exceed anything of the kind witnessed by the dweller of regions where the atmosphere is moist and the native tints of the rock concealed bv vegetation. The hills of New England when arrayed in all the gorgeous panoply of autumnal foliage are not more striking than the desert ranges of Utah when ablaze with the reflected glories of the sunset sky. The rich, native colors of the naked locks are then kindled into glowing lires, and each canon and rocky gorge is filled with liquid purple, l)eside whi(;h even the Imperial dyes would be dull and lusterless. At such times the glories of the hills are mirrored in the dense water of the lake : their duplicate forms appearing in sharp relief on the paler tints of the reflected sky. As the sun sinks behind the far-off mountains, range after range fades through innumerable shades oi! piu'ple and violet until only theii- highest battlements catch the fading glory. The lingering twilight brings softer and more mysterious beauties. IJanges and peaks that we"e concealed by the glare of the noon-day sun, start into life. Ft)rms that were before unnoticed, people the distant plain, like a shadowy encampment. At last each I'emote mountain crest appears .as a delicate silhouette, in which all details are lost, drawn in the softest of violet tints on the fading yellow of the sky. To one who only beholds the desert land bordei-ing Great Salt lak(i in the full glare of the unclouded sununer sun, when the peculiar desert haze shrouds the landscape and the strange mirage distorts the outline of the hills, the scenery will no doubt be uninteresting and perhaps even re[)ellent. But let him wait until the cool bresith from tlie mountains steals out on the plain and the light becomes less iatense, and a t-ansfor- mation will be witnessed that will fill his heart with wonder. The saline and alkaline shores of Great Salt lake are either naked mud plains, frecpiently white with drifting salts, or scantily clothed with desert shrubs. The absence of conspicuou.^ flowers is freipiently relieved by broad areas covered witii a peculiar plant, known as Snliconiia^ whi(;h flourishes by the side of this Dead Sea of the West, where all other vege- tation perishes. The Salieornia grows in fleshy stems, without leaves, r 80 LAKES OF NORTH AMEltlCA. ■ "^ If ■a ! j ' j 1%. and look"* not unlike hranehing coral. It is of many shades oi; red, pink, and yellow, thus still further increasing its resenihlance to groves of li\ ing coial. The white, alkaline desert is fre(|nently tinted by this strange plant until it glows like a lield oi iMpine flowers. There are many other interesting features to he noted hy the visitor to the great desert-lake of Utah, but its i)hysical and chemical history claims our attention at this time rather than its artistic setting. The streams Hewing to the lake rise in the high mountains to the east and are clear and limpid, and of such purity that only chemical tests reveal the presence of the mineral matte; they have dissolved from tlic rocks and soils. Several of these streams are truly rivers in volume, as well as in name, and send a naver-ceasing flood to the lake. Their com- bined volumes average throughout the year about 10,000 cubic feet per second.^ There are a number of fissure springs a1)0Ut the lake, or rising beneath its surface. In some instances these are hot and contain more saline matter in solution than is usually found in surface streams. These con- tribute a considerable quantity of the saline matter found in the waters of the lake, but it is Ijelieved that the amount thus derived is less than that furnished l)y streams from the mountains. This conclusion rests on incomplete data, however, as neither the volume nor the composition of all the springs is known. None of the springs supplying the lake, with a single known exception, of small volumes, are markedly saline The salts they contain are ac(piired largely during the upward jjassage of the water tlu'ough the i-ediment of former lakes and their influence on the chemistry of the present lake is more im[)ortant than in the case of any other lake in the same region. It is safe to conclude, however, that the combined volumes of the streams and springs now tributary to the lake, if not con- centrated by evaporation, would form a A\ater body in which no trace of saline matter would be apparent to the taste. Analyses of the waters of Bear river, of Utah lake, from which the Jordan flows, and of City creek, one of the numerous streams f}-om the Avest slope of the Wasatcl; mountains, give an average of about 0.2446 part per thousand of mineral matter in solution. This may be taken as the average composition of the surface stream flowing to the lake. As will be noticed on referring to the average conij)osition of normal rivers previously given, the mineral matter in these streams is nearly double the amount carried in the same volume of water by streams 1 G. K. Gilbert. " Lands of the Arid Region," Waaliington, 1879, p. 72. KKLATION OF LAIvKS TO CLIMATIC CONDITIONS. 81 id, pink, :)f lisiiiii: stnuige iiy other t-lakt! of I lit this I the east ical tests from the iibuiie, as heir eoni- c feet per g beneath ore saline iliese fon- waters of than that rests on tion of all e, with a inie salts the Avater chemistry cr lake in mhinetl eo f not eon- lio trace o f Iwhieh the from jams of ahont Ins may l)e Intr to thti f losition o streams is '.y streams in more hnmid re_i,'ions. This is due, in a measure, to the active evapora- tion that takes ])lae(' fiom them a!id from the lakes on their courses. The waters of (heat Salt lake have been analyzed at six different times. T..0 lesults of these several analyses are widely at variance on account of fluctuations in the volume of the lake. The dates at which the various samples analyzed wei'e collected and the total solids found in 1000 parts of water are here given : ' Datt! . . . 1S.')() siiiimuT LSd!) Auj;-. isTo Dec. ISS.") An-. ISS!) Ang. Ls!)l> ^s 1.1 11 l.l(i-J l.lL'li lls.L' l:!(;.7 KI7.-J Specific <;r;>''f 1.170 Parts in Kmh. __!.■_' 1.157 111.")..") l.ir)({ •JO').l Since the accompanying table of analysis of hike waters was com[)iled, my attention has been directed to the analysis given below, which in several ways is the most com[)let(} and satisfactory that has been pul)- lished. Analvsls of a samplk ok tiik Watku ok Cukat Salt Lakk. Collkcted Ai(UST !), isu-2:^ 1>Y E. Wali-ku. [Expresst'il in OrMiiis in :i I.itiT. Spfcitie (iiavity, 1.1.5fi.] Kl.lCMKST.S AXI) Uadrals. PKOIIAIII.E CoMllINATInX. Xa K r.i 7">.S-i.") :].!»•_>,-) . . . ().()"M XaCl K ,s() llfi.SliO s.7.")(> l.i...SO^ M^Cb M'4Sf), (aSO, FeJ), and AljC),, SiO o.Hlil l.-).()41 .j.:.'l(; S.L'tO (l.iKIl (I.OIS .M- Ca . . . . 4..S14 •) |-> J t'l ^<>j. () ill sulphates . Fe.,(),, and Al,(),, SiO.^ .... lU ),,(),,. . . . Hi- 3 .... ..... 1-JS.J7.S l-2.:y22 '2Mn (I.OOl O.OIS Trace . . . . Faint trace .Surplus SO.j Total ..... Total solids hy evajioration " " [duplicate] . . . (i.().")l •j:}s.l-J 2:i7.0'2.') The average comi)osition of the ccnnbined spring and stream waters tributary to the lake cannot l>e stated with accuracy, but. judging from ' A compilation of various analyses of the water of Great Salt Lake and a di-scussion con- cern inst tlieni, is ,i,dven by (i. K. Gilbert, ^lonop-apli No. 1, l'. S. Geological Survey. •^ SchooU>f Mines [Columbia College] (Quarterly, vol. 14, 1H',I2, p. 58. * A later detcriaination showed about 0.01 gram of Hr. in a liter. I ■fl* 9*4 LAKES OF NORTH AMKIUCA. sucli observations as bear on tlie (juestioii, it seems safi; to assume tliat tlieir min^^ed waters would coutaiu less tliau doulile llie ])ereeiitage of saline matter found in the surfaee streams. The assum[)tion that t!ie combined sjjring and stream waters woiUd contain alxmt (K'-\ part in a thousand, or three one-hundredths of one per cent of total solids in solu- tion, seems as close an ai)[)roximatiou as can now be reached. The waters of the lake durinij recent low stages have become nearly saturated with sodium chloride and sodium sulphate, and under certain conditions these salts are precipitated. The point of saturation for calcium carbonate is passed, and this salt is precipitated [)robaljly as ra[)idly as it h received. The waters are not rich in the (;omi)ounds of bromine, boron, lithium, and iodine, which frequently occur in " mothei- liquors," remaining when the more connnon salts have been eliminated by long concentration, and hence indicating the old age of a lake containing them. The recent analysis by Waller, however, shows these rarer elements to be present in somewhat larger (quantities than was previously su[)iK)scd. The length of time that would be required to charge Great Salt lake with the common salt it contains, under the present conditions, is estimated by Mr. Gilbert at about 25,000 years. i. The (quantity of sodium chloride, or connnon salt, held in the water of the lake is estimated at 400 million tons, and the sodium sulphate at 30 million tons. These iigures indicate the commercial importance of this great leservoir of brine. The separation of the common salt has alieady led to a consideral)le industry, as from 20 to 40 thousand tons have been gathered yearly for a considerable period. Tlie most extended and best conducted of these operations are carried on by the Inland Salt Company at the southern end of the lake. Evaporating vats covering more than one thousand acres have been constructed, and are supplied by pumps which deliver 14,000 gallons of lake water per minute. Pumping is continued through May, June and July, and the salt is ready for gather- ing in August. Dui'ing midsummei' the amount of water eva[)orated is 8,400,000 gallons daily. The yield of salt is at the rate of 150 tons per inch of water per acre. An average season's yield is a layer of salt about seven inches thick, which would be i)recipitated from forty-nine inches of water. The facilities for this industry may be judged by the fact that coai-se salt packed on cars ready for shipping, is sold at the works for one dollar per ton. The mother-liquor is allowed to go to waste, but it is to be expected that sodium sulphate and other salts contained in it will be utilized in the near future. KELATION OF I VKE8 TO CLIMATIC CONDITIONS. 83 Along tlie niiugi'-i of (rreat Salt lake, where the water is only a few inches deep, it hecomes so concentrated by evajmration that common salt crystallizes and forms a hrilliant white hiyer on the l)ottom. In fordin<^ an arm of tlie lake about a mile l)road, in order to reach Staiisbury island, the writer, in 1880, found a crust of salt formint^ a fflisteuinf^ pavement strong enough to support a horse and rider, but occasionally it would give way and lead to uncomfortable tlounderings in the black nuul beneath. The solubility of sodium sulphate is controlled largely by tempera- ture. In Great Salt lake in summer it is all dissolved and the watei-s are clear, but as cold weather ap])roaches it separates and renders the waters opalescent and somewhat milky in (;olor. In the dc]»th of winter, when the temperature falls below zero of the Fahrenheit scale, as it does at times for days together, this salt seitarates in great abundance and is thrown ashore by the waves in hundreds of tons, forming a slush-like mass on the beach looking like soft snow. On such occasions it can be gathered in practically unlimited quantities, l^ut is soon re-dissolved when the temperature rises. The brine of the lake is so concentrated that fish cannot live in it, but it furnishes a congenial home for small crustaceans known as brine shiimi)s (Artemia) and for the larvae of dipterous insects. These are abundant at certain seasons, but not in such vast numbers as in some of the more alkaline lakes on the west side of the Great Basin. It has l)een stated that the vast numbers of crustaceans and of larvae in these waters are due to the fact that there are no fishes or other animals in the lakes that could prey upon them ; a(iuatic birds, however, feed upon them in great numbers, but still the}' swarm in countless myriads. Their food seems to be minute algae of which several species have been described. As shown by the an.dysis given above, the principal salt in Great Salt L.ake is sodium cidoride. In the second example of the saline lakes described below the characteristic ingredients are sodium ijarbonate and sodium sulphate. (Jreat Salt lake may be said to be a mit lake in distinction from a number of water bodies situated especially on the w< st side of the (ireat Basin, which may with propriety be designated as alkaline lakes. Mono lake, California. — This lake, selected as the type of a series of strongly alkaline Avater-bodies in the desert basins of the Arid region, is situated in south-eastern California, within a few miles of the Nevada 84 LAKKS OF NoltTH AMKUICA. lioiUKliiry. It lies at tlie imnuMliiitt' fiistciii biise of tlu' Sierra Neviulu, from wliieh it receives pnietically all of its water supply, and occiipies one of the minor basins eomposinj^' the yivat area of interior (Irainaj^e known as the Great Basin. Its position on the wt-st side of tluf (ireat IJasiii and at the base of tlie yicat fauU s(ar[) forniino- the [Mccipitous eastern sloi)e of the Sierra Nevada, is similar to the situation of (ireat Salt Lake on the east side of the same broad desert area, and at tlie west ]>ase of the mat-nit lee nt fault scar[) forming- tin; abrupt western face of the Wasatch ran^e. Mono lidve, like many other enclosed water liodies of the Arid rcj^ion, is of ancient lineaLje, as is shown by numerous beach lines, carved by former water bodies, on the inner slopes of this valley. The hit^hest of these lines is from ('>70 to 080 feet above the present water surface. The hydrographic basin of Mono lake has an area of nearly 7000 square miles, and. as in the ease of the regitm draining to (treat Salt lake, is divided into two strongly contrasted portions. The southwestern part is numntainous and rugged, and bristles with serrate peaks that rise over six thousand feet above the lake's surface. On the mountains tlie snow- fall is abundant, and several small glaciei's exist in the higher valleys. 'J^he eastern i)ortion of the drainage l)asin is comparatively low. and is arid and desert-like in character. Little rain falls on this portion of the basin, and there are no perennial streams. Only occasionally is tlicre sulKcient precipitation to produce a surface drainage, and normally the rain w'ater and the water produced from the melting of the light winter snows, is al)soi'bed at once by the thirsty soil or returned to tlie atmosphere by evaporation. / To gain a eomi)rchensive idea of the geograi)hy of the interesting region about ]Mono lake, one shimld climb some commanding summit on the High Sierras, on its southwestern bolder, and study the inagnilicont ])anorama s])rea(l out at his feet. Let the reader come with me- to the siunmit of Mt. Dana, named in honor of the venerable J. D. Dana, one of the most prominent peaks overlooking Mono lake, and I Avill endeavor to i)oint out some of the more interesting features of the land we are studying. ; . ■ . The summit we have reached is nearly 13,000 feet above the sea. The only neighboring mount'..ins exceeding it in altitude are Mt. Lyell and Mt. Hitter, which rise with dazzling w-hiteness against the southern sky. From our stiition the entire Mono basin is in view, and much of its his- tory can be read as from a printed page. We are standing on one of the t DELATION Ui-' LAKKS TO CLIMATIC CUNlUTlUN.S. 85 liijifhest points on tlu! rim of a sliar[)ly dt'liiu'd liy(lr(»j,'iiii>lii(' Imsiii. Tlio (Iniiiiiij^i! from nil directions tcMids towiinls tin; ct'iitiu' and forms a lako from wliich tlu' waters I'scape oidy l>y evaporation. Wc ean trace neaiiy tlie entire honndary line of tlie i)asin, for tlie reason that tlie slopes are so plainly marked and the crest lines so sliar[)ly drawn, that there is no doul)t us to the direction that surfaco water would take. The coui-ses (»f the swift, lu'ii^ht stream descendinj]f the mountain can Ix; foUowed from their sources in meltiufj snow-lields, down through deep cafions to where they enter the lake. On the desert side of the basin, however, there are no streams, and hut indelinite traces of the (hy beds of former water-courses. There is no notch in tlu? rim of the basin to suf^tfcst a former outU't. The only possible point of discliarjj^i! for the watei-s when the ancient beaches scoring the inner slopes of the valley were formed, is far to the north, and concealed from view. Apparently at our feet, but in reality a mile in vertical descent below, lies the lake, a silent and motionless plain of blue. Should the wind chance to be strong in the valley, however, its surface would be rallied, the flash of breaking waves would reach the eye, and long lines of froth would streak its surface. At such times abroad fringe of snowy foam, produced by the cluuiiing of the alkaline waters, encircles the shores and renders their outlines unusually distinct. Apparently floating ou the surface of the lake, there are two conspicuous islands, the forms of which show that they are of volcanic origin. That these craters were built since the encircling waters fell below their level, is shown by their unbroken contours and by the absence of terraces on their outer slopes. Beyond the lake the In'own and barren land seems low and feature- less, because of the elevation of our i)oint of view. We can see far be- yond the limits of the drainage basin, in which we are now specially interested, land distinguish many of the desert ranges of Neviula rising above the purple haze enshrouding their base;-' and obscuring the lifeless lands between. The highest of these distant summits, which ai)pears like a spectral mountain floating in the sky, is even higher than the peak on which we stand, but its naked sides are scorched to a cinder-like redness by the desert heat, and no silvery stream can l)e detected in the wild gorges scoring its flanks. Its summit is seldom cloud-cap] )ed, and only in the depth of winter is its ruggedness concealed by a mantle of snow. To the right of the lake is a long range of craters built of fr.agment8 of volcanic rock tlirown out during many violent eruptions, and now (t r H 86 LAKKS OF NORTFI AMEUirA. B 1 1 formiiiif '-'onioiil piles witli ^nicefully Hwcepiiij,' outlines. Several of these now s lent volciUMU's rival Vesuvius in luMjjflit and l)eauty, hut from our elevated stations we can look down upon the dejiressions in tiieir sununits, and the ehiire ranj^e, althouj^h two miles in lenuntains the monotonous gray coloring of granite is hut partially concealed hy the scanty forests in the canons and valleys, or hy the mosses and lichens on the highei- snnxmits. Near at hand, hut across a deep intervening valley, rises Mt. Conuess, hare, rugged, a'ld grand. Twelve miles to 'the •■•outli, across a fragment of deeply ;':oded tahle-land, named the Kuna crest, are the spire-like peaks of Mts. Lyell and Hitter. Thi'oughout the year their summits ari white ^1 ith snow, and small glaciers can he distinguished in the folds of their lUgged sides. Keturning from this vision of wild magniiicence, the eye rests upon a scene hundjler in its charms hut not less pleasing. Between the naked crags forming the summit from which we have gained our com- manding view, and the highest limit of the i)ines, all twisted and deformed from unequal struggles with wind and di-ifting snow, there is a helt of rugged i)recipices and weather-heaten rotdvs that at certain seasons are hright with lichens and fringed with the purple and gold of alpine hlos- soms. These charming decorations on the mountain-'s hrow flourish with rank luxuriance in every cranny and cleft, and not infrequently are in such rich profusion that an entire sunnnit-peak is tinted hy them sis UELATION OF LAKKS TO CLIMATIC CONDITIONS. 87 of these nun oiir uminits, :s rising a luiiioi' rest line eve ciiii I not the II liase ut itli liikes iiioiliited •il)ally to Init lias At one system ot" J streams le valleys the more olor; l)ut coh)ring I' canons Its. Near ess, l)are, [u-nient of ike iteaks larc white [s of their ;, the eye lietweeu our eom- Idt'formed |a belt of Lsons are |)iue hh)s- rish with |ly are in them as with a twilijrlit gh)W. Tn thcwe eh'vated regions May-tlay is a festival of late summer, l»nt it Itrings with it a nuiltitude of charms that are unknown to dwellers in the woild helow. 'Die mountains h"ld out innnmeral)l(! charms to detain us, hut we must desci'nd in our fireside journey, and learn more of the strange lake, the setting of which was revealed from our station on the mou'ilaiii top. Our downward journey is through a dee[) goige witli nearly verticuil \>alls; ii; its bottom a swift, clear stream plunges from ledge t(» ledge, and rusiics through I'ocky clia..in.s witli a roar that never allows the echoes of the ' veals illV It Th stream of cold, delicious wat« ^ ause the chiiractci' of many creeks and rivulets that are rushing down the mountain side to the ever-thirsty valley ])elow. A few springs add their waters to the supply from the mountains, but none of them are saline, and their united volume is far less thnn the volume of any one of lialf-a-dozcn of the mountain torrents pouring into Mono lake. The present density of the lake water is the result of tiie long concentration by eviii)oration of the supply from the mountains. The area of Mono lake in the stunmer of iSIS:}, was :is 14 miles. Its surface is broken by two volcanic islands and by immerous crags, some of which are renniants of islands now nearly eroded away, Avliile others are formed of calcareous (U'ltosits precipitated about submerged si)rings. The soundings given on the mai), show that its maximum dei)th is 1.52 feet, and the mean depth about 01 or (52 feet, its elevation above the sea, when surveyed in 1885, was 0380 feet. In Pleistocene ^imes, Avhen great glaciers descended from the High Sierras and were ];)roh)nged several miles into the valley, the ratio between inflow and evaporation Avas changed, and the lake rose, but never sulli- ciently to discover au outlet. During the time of its greatest expansion, it had an area of 310 S(|uare miles, and formed an unbroken water surface 28 miles long from north to south, and 18 miles broad. Its maximum depth was then over 800 feet. The facts of greatest interest in connection with Mono lake are to 1)6 found in its chemical history. As sl;own in tlie analvsis of its watei-s given on page 72, it is strongly imi)rf.gnated with sodium and with car- bonic and sulphuric acids. The most probable combination of these and other substances present in the watei's is given below : ;i 1 68 LAKES OF NOKTH AMERICA. Hypothetical CoMrosrnox ok tiik Watkr of ^Iono Lakk. BV T. M. (HATAKn.l CONHTITIKNTH. (iKA.M.S IN' A LiTEIt. Pkk < kxt of Total ISOUDH. Silica, SiO., . . . . . Aluiiiiuuin and ferric oxide (Al2Fe2)03 Calcium cailn-iiato, CaCO,, . Majiiicsiiiiii carliimatc, MgCOj Sodium l)()rati'. Xa^H/)j I'otassium clilfjridc, KCl Sodium chloride, NaC'l Sodium sulpliatc, Xa^SO^ . S;diiim carbonate, XajCC^g . Sodium bicarbonate, NallCOj [Specific gravity, 1.045.] 0.0700 0.0030 0.00.")0 0.192S 0.2071 l.H3(i.-) lS..-)033 9.8(190 18.3506 4.385() 0.13 0.005 0.09 0.3() : 0.39 ■ 3.44 34.(10 18.45 34.33 820 53.4729 100.00 As may be seen in the above table, sodium carbonate and ])i('arbonahe form 42.53 per cent of tlie total salts held in solution. The total qnan- tity of theee salts contained in the lake is estimated a+ 92 million tons, the total saline content being 2 45 million tons. Owing to the cost of transportation and the high price of labor, tliis brine is not now ntilized, but it forms a reservoir that may be drawn u})on in the future. The waters of Owens lake, situated a hundred miles south of Mono lake, Avhere the commercial conditions are somewhat more favor- able, is already the basis of a large soda industry. Two small lakes on the Carson desert, known as the Ragtown ponds, or Soda lakes, also furnish large quantities of sodium carbonate and bicarbonate. Tliere are also several other lakes of the same general character in the western part of the Great Basin whicli have not yet been found of economic impor- tance. One of the most promising of these, from a Cv>mmercJal point of view, is Soap lake, in the State of Washington. The great abundance of sodium cacbonate and bicarbonate in Owens, Mono, and other lakes on the Avest side of the Great Basin, in contrast with the amount of these salts in the brine of (Jreat Salt lake and of other similar water bodies on the east side of the Great liasin, is due mainly to differences in tlu; character of the rocks of the two regions. The moun- tains on the west are largely formed of volcanic rocks, and yield alkaline 1 Ainer. Jour. Sci., 3d Ser., vol. 36, 1888, p. 149. [: Total i. L'arbonahe till qu.ui- ion tons, iil)(»r, this wii upon les south )re fiivor- Likes on kes, also liere are tern part 10 inipor- point of Owens, contrast of other [lainly to lie nioun- alkaline ?' t> cc a r, U- X 1 C < 2. o S* rr. u n 3 ^ ■t; n " o ^ « ii 'W :^ s <• « 1 .a 3 c« ii a Pr, c 3 X RELATION OF LAKES TO CLLMATIC CONDITIONS. 89 salts to the waters flowing over them or percolating through their inter- stices ; while tlie rocks of tlie eastern area are hugely .se.Unientary in origin, and supply sodium chloride in excess of sodium ^arhonate. Ihe cliemieal liistory of the lakes of the Arid region is not only an interesting an.l attractive study, but one of great economic importance, as they hold an alnmst unlimited supply of common salt, and of sodium ca.oonate and bicarbonate, sodium sulphate, and other salts in less abun- dance. Ihis supply is still farther augmented bv the deposits of former akes now evaporated to dryness. The salts precipitated from these ex- tinct lakes, in some instances, whiten the surfaces of desert valleys, but more frequently they are buried beneath or absorbed in the clays forming the smooth plains left l)y the evaporation of playa lakes • The importance of the lakes of the Arid region to those interested in salt and alkali industries is so great that the table on page 72 has been inserted to show the comparative values of the brines thus far analyzed. More detailed information in this connection may be found in the inibli- cations cited below.^ r S rini J «M ■ . • ^"'''■' ^^^^^^g'-aPh ^o. 11. _ I. C". Hussell, " Lake Mono " l. S. (,eol. Surv., 8th Ann. Hep., 188(i-87, pp. 287-200 _T r p„sc„ii " i. Waahino-ton " TT e n^^i c ,. ,. . ''l'^'"''"' ^.'.'- — L L. Kussell, Keconnoi.ssance n Washington U S. Geol. Surv., Bulletin No. 108. -T. M. Ciatan' "Natural Soda " V S (.01 Surv., Bulletin No. 60. -T. M. Chatard, " Analyses of the Water of slrAme ica^ Wa^Oreat Salt .^, .eho;/:i ^^^?C^^^^:LC:S'^:1^ CHAPTER V. THE LIFE HISTORIES OP LAKES. Lakes, like many other features of the earth's surface, as stated in our introductory clia[)ter, have their periods of growth, adolescence, maturity, decadence, and old age leading to extinction. The lives of most lakes are so long that human records cover only a small portion of their histories, hence their growth and decadence can seldom he traced by observing a single individual. By studying many examples, however, in various stages of development and decline, we are enabled to obtain separate links in the cliain of their existence, and may determine, at least in outline, the general course that they run. li}- having the theoretical history of a normal lake in mind, one is enabled to determine the period of life attained by .any special example that may be studied. The histories of all lakes are far from uniform. There are various accidents, as they may be termed, which introduce new conditions, and may renew their j'outh or hasten their decline. In general, lakes may be grouped in two great classes, in each of which the rule they play is in th(! main the same. The differences in the lives of these two classes depend mainly on climatic conditions, and have been noticed in descril)- ing fresh lakes and terrestrial saline lakes. The destiny of a lake born beneath humid skies runs in a somewhat definitely prescribed channel and (lej)arts in a marked way from the more varied life of a lake originating in an arid region. Tlie general outline of the history of each of the two classes referred to is briefly as follows : . Lakes of liiiniid Ite^'ioiis. — The normal lakes of humid regions are comparatively short-lived. The streams tiibutary to them bring iu sediments which tend to fill their basins, to these are added the debvis of water-loving plants and the hai'd paits of animals, and at the same time the streams flowing from them tend to cut down their outlets and drain them at lower and lower levels. Two processes thus conspire to diminish their volumes and shorten their existence. The deposition of sediment on their bottoms usually leads to their extinction more quickly THE LIFE HISTORIIIS OF LAKES. 91 IS stated lescence, 31- only a ence can iig many I'line, we 3nce, and run. By nabled to that may re various ions, and s may be ay is in o classes desei'il)- xke born unci and lating in the two regions I bring i'l lie debvis [he same [lets and Ispire to isition of (quickly than the lowering of tlieir outlets, for the reason that while incoming streams are frecjuently turbid and heavy with sediment, the outgoing waters are clear and tlierefore have Imt little power to erode. The clear outflowing waters deepen their cliannels l)y the slow process of chemical solution, but when the rocks over which tliey pass are soft and inco- herent, they may soon become recharged witli sediment and make rajjid progress in deepening their channels and in draining the basin al)ove. Tlie lives of various lakes may (lifter in length and liave minor variations according to local conditions, but tlie main features in their histories will conform to the same general outline. The filling of lake basins by sediment fie(][uently progresses more rapidly than at fii-st might be supposed. In some instances its rate may Ije observed from year to year, and attracts the attention of even the casual observer. In countries that have l)een long inhabited, there is sometimes histtnical evidence of the rate at which the boundaries of lakes have contracted. At the head of Lake Geneva, Switzerland, for example, the Rhone is bringing in large (quantities of silt derived from the gly this [)rocess their basins are transformed into alluvial plains, through whicli wander the streams that were tributary to the antecedent lakes. 'I'liese streams l)eing no longer robbed of the material they carrv in susj)ension. are enabled to attack their channels l)elo\v the forme/ lakes with energy, and to deepen and broaden them. The grade of the streams through the alluvial ])lain, marking. the former site of a lake, is increased, aiiil the removal of the soft lakebeds progresses as the channel belo\\' is deepened. Streams flow through alluvial })lains with slackened speed, and form winding channels, and swing from side to side of their valleys, thus reducing the general level. The load j)reviously deposited in the basin is again taken up and the deferred task of transporting it to the sea is resumed. Former lake- 1 Principles of Geology, 11th edition, 1873, vol, 1, p. 413. m LAKES OF NORTH AMEKICA. I I basins thus become terraced valleys, with streams winding through them in broad curves, and in civilized regions afford rich farming lands and charming sites for towns and cities. At a later period, if some outsiile influence does not change the course of history, the alluvial deposits are dissected to the bottom, the terraces of soft material are removed, and all records of the once beautiful lake may be lost. This transformation maj* require tens of thousands of years for its completion, yet the end is inevitable. The various stages in this general history might be illustrated by an abundance of examples. Thou- sands of lakes in the formerly glaciated region of northeastern America still retain the freshness of youth, and their nearly level bottoms may be considered as unborn lacustral plains. The terraced borders of Lake Cham- plain, and of the Laurentian lakes, mark the former extent of water bodies that have passed the youthful stage. Many terraced valleys in the Cordilleras record the former presence of lakes in basins that are now completely drained. In other localities, as in the " Parks " of Colorado, no terraces may be distinguished, but vestiges of lacustral sediment still floor their bottoms. Many valleys in the same region drain through narrow stream-cut gorges, but all other evidence of their having been formerly water-filled has vanished. The time required for these muta- tions is vast when reckoned in years, but to the geologist they are transient phases in the topographic development of the land. The even course of history, outlined above, may be varied somewhat, as when the outflowing stream is rapid and especially when falls occur in its course. Waterfalls are formed especially where streams flow over nearly horizontal strata where a hard surface layer rests upon shales or other easily eroded beds, as is typically illustrated at the Falls of Niagara. The ujulermining of the hard capping layer is effected by the removal of the soft beds beneath, and blocks from the brink of the precipice fall to the pool below and assist the swirling water to deepen a basin. A fall thus cuts back the ledge over which it plunges with comparative rai)id- ity, — in the case of Niagara the rate of recession is from 4 to 6 feet per year, — and may lead to the drainage of a lake before its basin has been deeply filled with sediment. The succession of the principal events in the hist jry of a valley may thus be hastened, but the ultimate results will be essentially the same. Many small lakes, especially in forested countries, where the surface waters filter through layei-s of vegetable d^'bris before gathering into rills and brooks, are filled mainly by organic agencies. Water plants, and THE LIFE HISTOIIIES OF LAKES. I 98 iprh them luds anil he course B terraces tiful hike s of years ;es in this i. Thou- 1 America lis may he ike Cham- of water eys in the ,t are now Colorado, iment still 1 through ving heen lese muta- , they are somewhat, [s occur in flow over shales or if Niagara, 'emoval of lice fall to In. A fall ive rapid- [6 feet per has been iUts in the [its will he the surface into rills lants, and especially Sphnf/num or peat moss, grow about their shores, and extend- ing outward, form a thick mat of intertwined roots and stems that float on the surface. The finer Avaste from this sheet of floating verdure falls to tlie bottom and forms a peaty stratum. To this layer contributions are made by other aipiatic vegetation, as the lilies, reeds, rushes, and many beautiful siilKXciuatic plants. It also receives the trunks of trees falling from the shore. The small lakes of the prairie region especially, are fre- quently transformed in this manner into 1' tutifnl fields of wild rice. In the central part of moss-encircled lakes, practically no mechanical sedi- ments are t1e[)osited, but mollusks, crustaceans, and fishes may tliere find a well sheltered home and thrive in such abundance that the bottom soon becomes covered with their remains. Microscopic forms also inhabit the water and their siliceous cases frecpiently accumulate so as to form thick la} ers, known as diatomaceous earth. A continiuition of this process under favorable conditions leads to the rapid extinction of small lakes. Tlie o[)en waters are converted i.ito hoga and swamps, on which forest trees encroach and still farther assist in the transformation. When these de^josits of organic matter are drained, they frequertly furnish rich garden lands. The lakes exterminated by this organic process in the drift-covered por- tion of North America, can only be estimated in tens of thousands, and probably equal in number the lakes still remaining. Lakes of Arid Regions. — On every continent there are broad areas where the skies are without a storm cloud for many months each year and the air is dry and hot in all but the winter season. The lakes in tliese desert regions have a different general history from their sisters whose banks are fringed with green vegetation and overshadowed by forests. Where the rainfall is small and e"»'aporation active, the lives of lakes depend on delicate adjustments of climatic conditions. As the barometer rises and falls in harmony with changes in atmos[)heric pressure, so en- closed lakes fluctuate in sympathy witli changes in humidity or in tem- perature. The ephemeral lives of playa lakes have already been described, but the larger lakes of arid regions, although subject to many fluctuations, may have a longer span o^ existence than lakes of corresponding size and similar topographic environment in humid regions. As enclosed lakes do not overflow, there is no loss of area owing to the lowering of outlet. Tributary streams bring in material both in solution and in suspension, all of which is left as evaporation progresses, and tends to fill their basins, but the volume of their waters is not directly diminished by this process. !»4 LAKES OF NOUTH AMKUICA. i'; I f' f I As their basins are filled, however, the watere expand and offer a greater snrface to the atmosphere, thus promoting eva|)orati()n. A continuanct' of this process results in so enlarging the water surface that in time evap- oration e(pials the snp[)ly and the water hody i)assi's to the condition of a playa lake. Sedimentation may raise the water surface so that an outlet is found before the playa stage is reached, thus transferring an enclosed and saline lake to the class normal to humid regions, already considered. The existence' of lakes in (;ountries where there is a close adjustment between precipitation ansitcd in enclosed basins are also protected, from destruction, as they cannot be removed by streams until some change inaugurates free drainage to the sea or to some lower basin. A continuation of aridity in a desiccated lake basin, results normally in the burial of the lacustral sediments beneath subaerial de[»osits, thus again insuring their preservation. To follow this subject farther would lead to a comparative study f>f the processes of erosion in arid and in humid regions, which is beyond the scope of the present essay. It will be seen from what has been presented above with reference to the normal course of the lives of lakes, that in s])ite of the many varia- tions they present, the seeds of death are planted at their birth, and they are destined, sooner or later, to pass away and give place to other condi- tions. Interruptions of the even tenor of the lives of lakes, in lioth arid and humid regions, such as the effects of u[)heaval and depiessicm of the earth's crust, earthquakes and volcanic erui)tions, might be considered, bat these abnormal incidents, like the acicidents in human lives, cannot be foretold, and apply to individuals rather than to classes. CHAPTER VI. 3 STUDIES OF SPECIAL LACUSTRAL HISTORY. It will iippear to the reader of the i)reee(liiig elmpter' that not only are lakes ephi iiieral features of the earth's surface, but even the changes they make in the to[)Ocrraphy of their shores, altliougli perliaps engraved in solid rock, are of shox '. duration in comi)arison with the length of the eras into which the earth's history lias been subdivided. Tiie lakes of Pleistocene times, liowever, left records which in many instances are still legible, and form a connection between historical and the most recent geological times. As examples of extinct lakes w-hose histories are still clearly legible, a brief account will be given of former water bodies of the Laurentian l)asin, and in the region now draining to Lake Winnepeg, Avhere the climate is humid, and of two formerly extensive lakes of the Arid region. PLEISTOCENE LAKF.S OF THE LAUHENTIAN BASIN. Long curving ridges of gia >'el having the appearance of great railroad embankments, following the general trend of the shores of lakes Ontario and Erie, but usually at a distance of several miles from their present borders, wcn-e noticed at an early day in the settlement of New York, Ohio, and Ontario, and correctly interpreted as l)eing the records of previous high-water stages of the lakes they encircle. These ridges became high- ways of travel as civilization advanced, and gave origin to the term "ridg(! road" still to be seen on local maps of the region referred to. These ricif^es and other associated records have claimed the attention of geolo- gists and others and have been made the subject of special incjuiry. The territory traversed by them is so extensive, however, that their study is still far from complete. The ancient beaches about lakes Ontario and Erie have been followed and studied, esi)ecially by G. K. Gilbert, in New York and Ohio, and by J. W. Spencer, in Canada. The records of former water levels north of Lake Superior from Duluth to Sault Sainte Marie, have been traced and mapped by A. C. Lawson. To the south of Lake Superior the ancient shores have been systematically followed by F. B. Taylor. Many other HTUDIKS (U- Sl'KClAI. LACCSTltA I- IIISTOKY 97 . not only e changes 1 engraved (jtli of tlu' e lakes of es are still lost recent rly legible, Liinrentiau Avliere the aid region. at railroad es Ontario |eir present ■few York, |of [)revions 'iune liigli- lerni "ridge :o. These n of geolo- lury. The lir study is In followed lio, and by lis north of Itraeed and pe ancient llany other observers have also contributed to tliis study, but not in such a methodical manner oh those whose names have just been mentioned Some of the |)roblems that have ])resented tiiemselves during this investigation have not yet been satisfiictorily explained, l)Ut at least an outline of the I'leis- tocene history of the Laurcntian basin may be presented with the under- standing tliat it is to be niodilied as additional facts are obtained. The most dramatic episode in the geological history of North America was the formation during I'leistocene time, of glaciers many hundreds of feet in thickness over the northern part of the continent. The ice advanced from the north and not only covered the Laurcntian biisiii, l)ut spread southward beyond the southern border of its watershed. The ice i(»vered this region with various advan( js and retr.ats tor thousiuids of years, and when it linally withdrew, the inunediate ancest(>rs of the present (Ireat Lakes were born. There are severel observations tending to the conclu- sion that during an interglacial time when the ice receded far north of its maxinmm limit, lakes were formed in the same basin, but in this connec- tion there is little evidence to claim pofjular attention. Previous to the Glacial e^joch or the (treat Ice age, as it is frequently termed, the region under review was an old land surface with riveis flow- ing across it to the sea. Its draini>ge system was well dcvclo})ed and the streams meandered through broad valleys, bounded in part by steep escarp- ments. In general relief, it nuist have resend)leil the upjier portion of the Mississippi valley as it exists to-day, where the topogi'aph}- has not l)cen modified by glacial action. The conclusion that the Laurentian region was exposed to erosion for i long period previous to the Glacial epoch, is based on the character of tht- ivlief of the hard rock surface now covered in part by glacial deposits and on the fact that no sediments of younger date than the C'arlioniferous period, with the possible exceptions of terranes of Cretaceous age in por- tions of iNIinnesota, occur within its borders. It may be suggested as a tentative hypothesis, that previous to the rilacial epoch the greate • part of the Liiurentian basin discharged il> waters southward to the Mississippi, and that during the iirst iidvance of the ice from the north, the drainage was not obstructed so as to form importiini lakes. This suggestion rests in part on the fact that no lake deposits have yet been found beneath the lowest sheet of glacial ddl)ris lining the basin, — this negative evidence is of little weight, however, as such de})osits, if they exist, would be mostly beneath the present lakes and therefore exceedingly difficult to discover, — and on the character of an 98 LAKES OF NOUTII AMKIIK^A. ancient rivor viilU'V IciKlinj,' sontli from (he sontlicrn ont and west low [)aitin<^ ward to the etween the arlier lakes vest de})res- outrtowliifj ay instances ;s near Fort waters that nilar outlet referred to. ties on the northward, th another. higher hike south was , the site of o the level I'a river was lowest sag iited in pre- le work of as to drain t a pre-glacial 3nnined. y i [ft 1 V 1( o n e( (li o> >sli fo ca be th( STUDIES OF SPECIAL LACUSTKAL HISTORY. m Lake Erie at a lower level tliiui at present, the shore lines \o\v forming about its margin will l)e abandoned and another line added to the records aljout its l)ord(jrs. For a long period in tlie history of the Ontario basin, tlie outflowing water escaped through tlic Mohawk valley. New York, as lias been shown by (xilbert, and the discharge of a large part of the Laurentian l)iisin reached tlie seii by that channel. The series of well dehned water-marks about the O.itario basin formed at this time, has been named the " Iroquois beach," by Spencer, and the ancient lake outlined by it is known as " Lake Irfxpiois."' When the ice front retreated still farther northward, the present course of the St. Lawrence was uncovered, the Mohawk channel was abandoned, the water surface fell, and existing conditions were establislied. During various stages in the enlargement and subseqiu'nt contr:iction of the lakes about the southern margin of the Laurent'dc glacier, beaches were formed which in some instances, as has been shown l»y Frank Lev- erett, in Ohio, are continuations of the moraines deposited at the margin of the ice where lakes did not exist in front of it. In otiicr instances moraines ojcur that are partially or wholly buried beneath lake sediments and mark the boundaries of the ice front where it was margined by water bodies. At many localities where tlie former wAter markings are well pre- served, they were made on low shores, and took the form of ridges re- sembling railroad embankments. The highest of these ridges marks the maximum limit of the water bod}' about which it was formed. As the water fell the higher beaches Avere abandoned and others constructed at levels determined by lower outlets. When the bordere of the Ldvcs were of ice. shore, records are wanting, but as stated above, buried nioiMines may mark the position of the dividing line between the water and the C(mfining ice. While the ancient beaches were in process of construction (he alain- dant sediments carried into the lakes, were s][)read out as slu ets of (.-lay over the deeper portions of vhe basin, and at the same time the areas near shore received deposits of sand. Icebergs broke away fnmi tlie glaciei-s forming ihe northern shores of the lakes, and floated over their surfaces, carrying stones which were dropped as tlie ice melted, and became im- bedded in the clay on the bottom. These dei)osits surioiiiul the ju'esent Laurentian lakes and luiderlie them. About the lioiders of Lake Erie they appear as a stiff blue clay, — known to geologists as the " Erie clay," I',- 100 LAKES OF NOllTH AMlililCA. m charged in some instances with large houlders of crystalline rock, — and as sheets of yellow sand, known as "delta sands," which rest on the clay, and are especially ahundant where the mouths of ancient streams were located. Ahont the shores of Lake Sni)erior and frequently extending many miles inland, there are ancient clay deposits of a pink color, that were accumu- lated when the l«isin contained a much larger sheet of water than at present. The heaches ahout the borders of the Laurentian lakes were originally horizontal, but as has been shown especially by (rilbert and S])encer, they are in many cases no longer in their original jjosition. Changes in the elevation of the land liave occurred and the beaches liave been carried u[) or down with it. The amount of change in level shown by the warping of the beaches abovit Lake Ontario is considerable, and illustrates the character of the slow u[)heavings and subsidences known to be in progress over wide areas of the earth's surface. It is stated by Gilbert^ that "the old gravel spit near Toronto, belonging to what is known as the Davenport ridge, is forty feet higher than the contemporaneous gravel spit on wliich Lewiston is built ; at Belleville, Ontario, the old shore is 200 feet higher than at Rochester ; at Watertown, N. Y., 300 feet higher than at Syracuse ; and the lowest point in Hamilton, Ontario, at the head of the lake, is 3"25 feet lower than the highest point near Watertown. Frf)m these and othei' measurements shown on I'late 18, we learn that the Ontario basin with its new attitude inclines more to the south and west than with tlie old attitudes."' This rj(>neral tiltinj'' has throv»n the waters of Lake Ontario westward and flooded small tributary valleys so as to drown them and make miniature flords. Movements in the earth's crust Avere also in progress during the long period in which the ancient lakes of the Laurentian basin were making their various records, as is shown by the fact that the abandoned beaches do not all lie in })lanes parallel Avith es'ch other. The higliest of tlie ancient beach lines about the north shore of Lidl~2-">7. * "Sketch of the Coastal Toixijrrapliy of the Xovtii Sidi' of Lake Superior," in 20tli Ann Rep.. Minnesota, Geol. and Nat. Hist. Surv., pp. 1S1-2S!). STUDIES OF SPECIAL LACUSTRAL HISTORY. 101 In -iOtli Ann ai)pi-oxiniately pamllel with it. Observations on the amount of defoiina- tion that this beach has suffered, are not as extended as coukl be desired, but near its western extension there is evidence of a cliange of level of about one foot per mile. liecent observations by F. B. Taylor' in the legion adjacent to Lake Superior on the south, have shown that ancient Ijeaches may be clearly recognized at many places between Duluth and Sault Sainte JNIarie. The facts recorded by Taylor supplement in a very interesting manner the work of J^awson on the nortliorn side of the same basin, although fai-ther study is necessary before tlie entire history of the great predecessor of Lake Superior can be Avrittcn. At the south, the highest beach has an eleva- tion of from 512 to 588 feet above Lake Superior, or from 1014 to 1190 feet above the fea. Taylor suggests that when the entire outline of the highest beach at the north shall have been traced, it will be found that there were straits connecting the Superior basin with that of Hudson Bay. This Mould imply a submergence of a very large portion of the North American con- tinent to a depth of over a thousand feet. The erosion produced by the movement of ice sheets many hundreds of feet thick, over the Laurentian basin, modified and subdued the pre- vious relief, and tli> ddbris left Avhen the ice melted covered the country witli a sheet of superficial 'leposits to such a depth that the character of the underlying hard-rock topography is only occasionally revealed. The depth of these glacial deposits over 'reat areas, as in Micliigau and Wisconsin, is from one to two hundred feet, but is probably of less average thickness in Ohio aiid New York. All pre-glacial drainage channels were either olistructed or obliterated and a new surface given to the land. The drainage was thus rejuvenated and is still innnature. The effects of glacial plantation and of glacial deposition, in forming the basins of tlie present Laurentian lakes, has been pointed out in discussing the origin of lake basins. In this brief sketch I have endeavored to show that the history of the Laurentian basin includes a study of the liard-rock topography as it existed previous to the Glacial epoch ; the disturbances and changes in drainage i)roduced by the ice invasion and by movements of elevation and dejjression; the obstruction of the ancient waterways by glacial deposits ; and the origin of new chainiels of d'ljcharge, as the glaciei-s 1 " A rcconnoissance of the abandoned shore lines of the .outh coast of Lake Sn])erior," in Am. Geol., Vol. 13, 1894, pp. 305-383. 8ee also more recent papers in the same journaL 102 LAKES OF NOUTH AMKUICA. ; passed away, — all of these links in the ooniplex history have not been completely worked out, and this attractive Held is still open to the geolo- gist and geographer. In conclusion, it is Imt t'air to state that while the liistorv of tlie Laurentian basin outlined above will, I believe, be accepted as in tlie main correct by most geologists of the United States, whose attention has been directed to the subject, it is widely at variance witli the coiudusions of at least two Canadian geologists. Sir .1. William Dawson maintains, if I understand his hyi)othesis correctly, that the sea, laden with icebergs, invaded the Laurentian basin in Pleistocene times, and that the ii">rainesand other deposits occurring in it aiul over a wide extent of adjacent country, and believed by most observers to l)e of glacial origin, are shore accumulations, and that icebergs and floe-ice played an important part in their formation. The ancient beaches about the Laurentian lakes, while considered as true shore lines by S[)encer, are tliought l)y him to have l)een formed at sea-level durinsr a time of continental submeruence, and that the ocean had free access to the basin. It may be that in these summary statements I do injustice to the views of the gentlemen referred to, Ir.it the conclusions indicated are so widely at variance with a vast body of consistent evidence gathered by a score or more of skilled observers, and is so directly <)p[)osed to my own observations, both of living glaciers and of the records of past glaciation, that they (h) not seem at present to l)e open to protital)le discussion. A subsidence of the eastern border of the continent during the later stages of the Glacial e[)och, or following its close, throughout a belt widening from New York city northward, and including the valley of Lake Champlain, is well known. When the studies leading to this con- clusion are extended to the basins of the Laurentian lakes, however, not only is there an absence of salt-water shells and other evidences of marine occupation, but, seemingly, positive evidence of lacustral condition. The region to the north of Lake Superior has not been sufficiently studied to admit of an opinion being reached in reference to the questions just considered, from the records there obtained. It may be found that the highest shore-line in the Superior basin was formed by a water body in direct communication with the sea to the north, as suggested by Taylor. Should this hypothesis be sustained, it would add an interesting cliapter to the history of the Superior basin, and render a review desirable of the evidence of a similar nature in the eastern portion of the region now drained by the St. Lawrence. not l)0('n the geolo- iiy of tlic us in tlie Mition has ^nt'lusions itains, if 1 fs, invaded 1 and other Antrv, and imdations, t'oiiuation. side red as formed at the ocean ice to the ted are so liered by a o my own sjfhiciation, lion. -• the hater ut a belt valley of ) this con- vever, not of marine on. ifhciently (^nestions nnd that ater body ested by iterestini^f desirable le region STUDIES OF SPKCIAL LACUSTKAL HISTOltV. lua »- The views of Dawson and Spencer are set forth in the pub lications mentioned in the following footnote,' nnd shou (1 be attentively studied by all who undertake to re id the history of the Laurentian basins from the original records in order that their conclusions may be fairly tested. Lake Agassiz. At the tinu' the remarkable changes described above were taking place in the i^aurcntian l)asin, there were corresoonding revolutions in the geogra[)hy of the region to the northwest whii'h now drains to Lake Winncpeg and thence through Nelson river to Hudson l)ay. It will \h' ri'adily seen on glancing at a niaj) of Canada, that if a glacier of the i-oiitinental type should advance southward from the Hud- son bay region, the drainage would be obstructed ami a lake formed over the country of mild relief surrounding Lake \Viinie[)eg and the Lake of the Woods, and extending southward through the Ked i{iv( r valley, far into Minnesota. Such a lake would discharge southward, and contribute its surplus waters to the ^Iississii)})i. Should the hypothetical glacier re- ferred to advance until it occupied all of the Winncpeg basin, the lake about its southern margin woukl be obliterated, and there would be free drainage to the Gulf of Mexico. Shouhl the glaciei- then retreat to the north of the divide now se}mrating the waters flowing southward to the Gulf of ^Mexico from those flowing northward to Hudson bay, a lake would be born about tlie margin of the ice, and would incres":.e northward as the ice retreated. When a channel leading northward was uncovered and rendered available as an outlet for the lake, the ponded waters would have their level lowered and their area contracted. The study of the Pleistocene records in the Red Kiver valley and thence northward in ^Lanitoba, has shown that changes very similar to those postulated above actually occurred. The evidence of the former existence of a large lake in the Red River valley was observed as far back as 1823 by Keating, the geologist of the first scientific expedition to that region. Subse(pient contributions to this investigation have l)een made by several observers, and notably by J J. W. Dawson, "The Canadian Ice Afje," Montreal, lS!i:>; .J. W. Spencer, " Tlic De- formation of InKjuois Beach and Birtli of Lake Ontario," in Am. .lour. Sci., .ser. ;!, vul. -lO, 18iH», pp. 44;]-4.")l ; J. W. Spencer, "Deformation of tlie Algon(|uin Reach and tlie Birth of Lake Huron," in Am. .Jour. Sci., ser. H, vol. 41, 18!H, pp. 12-21; .T. W. Spencer, "I'osi- I'leistocene Subsidence versus Glacial Dams," in (ieol. Soc. Am. Bull., vol. 2, 18!(1, pp. 4O0-474. 104 LAKES OF NORTH AxMEUICA. fn Gen. G. K. Warren, who first explained the origin of the valley now occupied by Lake Travei-se, liig Stone lake, and the Minnesota river, by showing tliat it was excavated by a stream flowing to the Mississippi from a former lake to tlie north. This ancient river, whose sonrce has long since been sapped l)y northward drainage, has been named lliver Warren, after its discoverer. The great lake that formerly flooded the Winnepeg basin, and dnring its highest stage overflowed through River Warren, has been named Lake Agassiz, by Warren Upham, in honor of Louis Agassiz, Practically all of the facts and conclusions here presented concerning tlie history of that remarkable lake, have been made known through the long-continued and skillful investigations of Upham, under the auspices, at different times, of the geological surveys of Minnesota, the United States, and Canada,^ respectively. The Red River of the North rises in the western part of Minnesota, and receives the tribute of Lake Traverse, situated on the Minnesota- Dakota boundary, and at the southern limit of the country formerly flooded by Lake Agassiz. From Lake Travei"se the present drainage is northward through narrow channels sunken in the sediments of the former lake. Between the streams there are broad, nearly level, inter- stream spaces, forming typical examples of new-land areas, on which shallow ponds form during rainy seasons. About the borders of this broad, level extent of prairie land, now transformed into wheat fields, there are gravel ridges which mark the surface level of the former lake at various stages. These ancient beaches have been traced northward and found to diverge toward tl»e northeast and northwest when the central area of the old lake was approached, and have been mapped so as to show approximately the extent of the water body that built them. By patiently following these ancient shore-lines, it has been demonstrated that Lake Agassiz covered a region about 110,000 square miles in area. Its diameter from north to south was G75 miles, and from east to west, in the wider portions, varied frqm 225 to 300 miles. It was the largest of the Pleistocene lakes of North America thus far discovered, and exceeded the combined areas of the present Laurentian lakes. The rim of its hydro- graphic basin embraced a region not less than half a million square miles in area. At the site of Lake Winnepeg the ancient lake was 090 feet deep. 1 A report on these investigations appeared in the Geol. and Nat. Hist. Survey of Canada, Ann. Kep., vol. 4, 1888-i), pp. 1-160 E, and a monograph on the same subject is soon to be issued by the U. S. Geol. Survey. STUDIES OV SPECIAL LACIJSTHAL HISTOKY. 105 One of the most interesting discoveiios in eonneetion with tlie beaches of Lake Agassiz, is that they are no h)nger hcn-izontal, and besides do not lie in phiins tliat are parallel one with another. TIk; highest water line when followed nt)rtlnvard has been found to rise at the rate of 200 feet in 300 miles. There are five beaches that are especially })rominent and mark a lingering of the lake surface at their respective horizons. The higlu!st of the series, known as the Herman beach, when traced northward from the southern end of the Ked Kiver valley, has been found to divide into several ))eaches at different levels; the vertical intervals between the division imaeasing northward. The meaning of this fact seem.s to be that the land was rising at the north at the time the beaches were formed and at the same time the surface of the lake was lowered by reason of the opening of new outlets. To the north of Lake Winnepeg the higher of the ancient beaches are absent and the lower ones difficult to trace. The countiy still farther toward Hudson bay is low and does not present a barrier that under any plausible hypothesis could have been made to act as a dam to retain the waters of Lake Agassiz. What then could for a time have reversed tiie drainage and led to the formation of a lake over a hundred thousand square miles in area? The origin of Lake Agassiz as explained by Upham, is in harmony Avith the history of the former lakes of the Laurentian basin. It is su})- posed to have owed its origin to the presence of a vast ice sheet over the Hudson bay region which dammed the northward drainage of the Winne- peg basin and caused the waters to rise until an outlet was found at the south and River Warren began to flow. When the ice retreated, new outlets at lower levels became available at the north and the waters fell, but lingered for a time at the horizon of each of the various beaches that have been referred to, at lower levels than the Herman beach. There are facts in connection with the ancient floods of the Laui-entian and Winnepeg basins, which seem to indicate that the weight of the ice during the Glacial epoch caused the land to subside, and that when the ice melted an upward movement was initiated. Tliese movements, and also the attraction of the ice body to the north of I^ake Agassiz, have been thought to explain the gradual rise of the ])eaches when traced northward. The strange transformation that the Winnepeg basin underwent in Pleistocene times, leads one to wonder if in the region now drained hj' Mackenzie river, and occupied in part by Great Slave and Great Hear !1 1 lOG LAKES OF N'OKTH AMKUICA. lakes, there may not be equally wonderful records awaiting the coming of the patient in(iuirer. ht^;' Pleistocp:ne Lakes of tffe Ctueat Basin. Diu'ino- the time of great elimatic changes that witnessed the birth, growth, and decadence of the great lakes of the Jy.airentian and Winiiepeg basins, described above, e(inally important tluctnations occurred in tlie lakes of the Arid region. Many of the valleys of Utah and Nevada, and of adjacent areas both north and south, that are now parched and desert- like throughout the year, were then Hooded, and in some instances tilled to the brim so as to overflow. All of the enclosed lakes west of the Uocky mountains were then of greater size than at present and underwent marked changes in sympathy with the advance and retreat of glaciers on neighbor- ing mountains, and had their oscillations controlled by the same causes, viz., variations in i)recipitation, evaporation, and temperature. Of these numerous water bodies there were two of broad extent Avhich may be taken as types of their class and will serve to give an epitome of the history of their time. The two ancient lakes referred to are IJonnc- ville and Jiahontan* aiul are represented on the map forming Plate 19. Lake IJonneville was named by (iilbert in honor of Cap'ain B. \j, K. Bonneville, U.S.vV., who made a bold explorarion iut(^ the wilds of the Rocky mountains in 1833, and was the first person to gather reliable information concerning the region formerly occupied by the great lake now bearing his name. The reader will perhaps liave an additional interest in the following sketch, when he recalls the "Adventures of Captain Bonneville," so graphically described by Washington Irving. Lake Lahontan first received definite recognition in ihe re})orts of the 40th Parallel survey luuler the direction of Clarence King, and was named after Baron LaHontan, one of the early explorei-s of the Mississippi valley. Why LaHontan's name should have been thus connected with a region more than a thousand miles beyond his farthest camp, in preference to the names of men who boldly crossed and recrossed the land referred to when it was a trackless desert infested wi*h roving bands of savages, I must leave to others to explain. As siiown on the accompanying map, Plate 19, Lake Bonneville occu- pied viie basin in which Great Salt lake now lies, on the east side of the 1 Clarence King, U. S. Geol. Exploration of the 40th Parallel. Vol. 1, 1878, pp. 400-520. — G. K. Gilbert, "Lake Bonneville." U.S. Geol. Surv., Monograph No. 1, 1890. -L C. Rns.sell, " Lake Lahontan." U. S. Geol. Surv., Monograph No. 11, 188.'>. ) coming of ^AKKs OK N,„frii Amkhi, A. rr-ATK i!). the bivtli, Wiiuu'pcu- ■red in the evada, and and dt'sert- mces HIIimI tlie Rocky :;nt inark('(l I neiji'hljoi- uie causes, tent wliicli epitome of ire Bonne- late 19. II n. L. E. lids of tlie er reliable ^reat lake additional sutures of rving. arts of the vas named ppi valley. Ii a region ference to eferred to savages, I viWe occu- ide of tiic pp. 490-520. 890. - I. C. i, STl'DIKS OK SPKCIAL LACUKTItAL MISTOnv. 107 Great Masiii, while Lake Laluuitaii Hooded a st-russ of irn-'pfular valleys on the west shhi of the saiDt; jri-eat area of interior (h'aiiiaf,^' and is now repre- senti'd hy Pyramid, W'innennicea, Walki'r, Cai-son, iind IIinnl)ohlt hikes, Nevachi, and hy Honey hike, California. These two ancient lakes were eonteniporaries, and, althon<,di differinpf in their histories, ])ear similar testimony in reference, to cdimatii' chanifcs and .tl sni>i»lement t'ach others records in a reiii;nkal)l»! maiinei ikal)h 'II leir hydronrii[)hic hasins joined each other in noi lii-easlern Nevada, for a distance of abont twenty-live miles, and toj^ether occupiiMl the entire width of till- (Jreat IJasin. Lake Uonneville received its water supply from the Wasatch and I'inta monntains, then snitw-clad thron<,di(»nt the year and hoklinj^ glaciers of the Ali»ine type in many of their valleys. Several of the ice streams on the precipitons western slope of tin; Wasatch monalains reached nearly to the ancient lake which washed the hase of the range, and one of them was prolonged for a short distance into its ■waters. Lake Lahontan derived its principal water su[tply from the Siena Kevada, which formed the western rim of its drainage basin for a distance of 250 miles, and, like the eastern borders of the Honneville basin, was glacier-covered. liuke Bonneville at the time of its niaximnin extension had an area of 19,7*)0 sipiare miles, and a hydrogiajdiic basin 'tii.OOO scjuare miles in area. The more irreynlar water surface of J^ake I^ahontan was 8.4:22 sipiare miles in area, and occupied the lowest depressions in a hydro- graphic basin containing 40,7 7 '> square miles. The great size of the hydrograi)hi(! basins of these lakes in comparison with their extent of water surface, is a noteworthy feature. The ratio of the extent of lake sui'face to area of hydrftgraphic basin in the case of Lake Bonneville was as 1 to 2.6, and in the case of Lake Lahontan about 1 to 5. The corre- sjjonding ratios in the basin of Lake Sujjcrior are as 1 to 1.72; and for the combined Laurentian lakes as 1 to 8.11*. The small extent of the ancient lakes of the Great P>asin in comi)arison with the areas draining to them, more especially in the case of l^ake Lahontan, indicates that the climate of their time was not markedly humid. The maximum de^jth of Lake Bonneville as recorded by beach lines on the mountain forming its shores, and on the precipitous islands now rising in (treat Salt lake, w'as lOf)'^ feet. Tlu^ greatest dejith of l.,ake Lahontan was 880 feet. The most striking difference in connection with these two ancient seas is in reference to overflow. The waters of Lake Bonneville rose I 108 LAKKS OF NOKTH AMKUICA. until they found an outlet and escaped through a elianiiel leading north- ward from ('acJH' valley, in I tali and Itialio, to, Snake river and thence to the ('nlniul)ia. The ontHowiniu; sticani at its source crossed incoherent alluvial deposits and lapidly cut down a channel of disciiar^-e to a depth of 870 feet, thus lowering,' the lake; hy that amount. I)urin<,' this episode; in its history the lake was fresh, hut at later stajjfes, when its surface fell helow the level of the hottom of thtr chainiel of dischari>ly of Lake I^ahontan was less ahundant and it never rose so as to liiul an (uitlet. Its waters were perhaps hrackish duriufT its higher stashes, and hecame saline and alkaline as concc^ntration j)ro;^iessed. Kach of these hdces had two hififh-water statues, separated hy a time ol' low water and prohahly of complete desiccation. The second hi<,di-water stage in each instance was the more marked of the two. These fluctua- tions are indicated in the f(»llowing dia' mountains and the eharaeteristie ttipojfia- phy due to tlie wmk of waves anil eurri'iits on theii' Ittwfr slopes. 'I'he ■lianntd of ilis('har<>'e lowt'ifil until a sill tif resistant liineston enannei oi ins('nar<,M' was lowfreii unui a siii tn resistant limestone was reaehed wliieh determined the httri/.on of the strongest and hest devtdttpetl terraces and emhaidvinents in the hasin. A well detined heaeh at this htui/.on is knt)wn as the " Pi'ovt) heach." the name In iny dcrivetl from the ttiwn tif l*ri>vt), Utah, which stantls on a hroad delta ftirmed hy the sedi- ment of l*rovo river, when the lake stt»od at the hori/.tm of its h)West point of (lischar<,'e. The waved)uilt sti'uetures inarkinrm as if al)an(h)ned hy the waves hnt yesterday. In the Lahontan hasin the shore tt>i)Ot>iapliy was never stroiififly j)roiiounced. Flnctnatitnis i>f level were not controlled hy an ontlet, and the nnnicrons islands and heatUands diminished the intlnence of the wintl and checked the action of waves and cnrreiits. The chemical histories of lakes IJonneville and Lahontan are fully as instructive and of as crreat interest as their physical chanj>es. In this connection, the liasin of Lake Lahontan has heen ftminl to exceed its comi)anion in the completeness of its records. The escape of the waters of Lake Bonneville insured its freshness dnrint'' a part of its history. The ahsence of an outlet for the waters of Lake Lahontan led to a hii>h def^ree of concentratit)!!. When lake waters arc coiK^entraved hy evaporation the lirst snhstance to be precii)itated, as previously described, is calcinm carbonate. About the shores of Lake Bonneville there are in favorable Itu-alities, consider- able deposits of this stibstance in the form of coral-like incrustations known as calcareous tufa. It appears on rocky points and forms a cement for gravel and sand on the outer borders of some of the terraces, but is insignificant in amottnt and simple in character, when compared with the truly immense accumulations of a similar nature in the Lahontan basin. 110 LAKKS OF NORTH AMKUICA. !!.'■' vi Tlu' pivc'ii»itati()ii of caleium carbonate ffom l;ikc waters takes place priiudpally in two ways: it may separate in tlie opiMi lake and tall to the bottom in a finely divided state and become mingled with mecliaidcal sediments so as to form marls, oi' it may be }>reci[)itaied where solid rocks occnr and cover them with a dense incrnstation. The ability of ordinary snrface waters to dissolve ealcinm carbonate, dejiends maiidy on the carbonic acid gas they hold in solution. Lake waters lose their dis- solved gases most rapidly whi're they form breakers along the shore, as in such instances they are most thoroughly aerated. For this I'eason, the bohU'st headlands are apt to receive the heaviest deposits of tufa when the waters dashed against them became concentrated. It is at such ^)calities that the princi[)al deposits of tufa in the lionneville basin occur. It ha[ti)ens also that calcium carbonate has a tendency to accumulate about solid bodies, not only because they afford a stable supjuu-t, but for the additional reason that points and angles indm-e crystallization. Calcareous tufa was deposited in vast (piantities about the shores of Lake Lahontan Avhei'ever there were rocky slopes and in increasing abundance from an horizon high iip on its borders down to the deepest point now exposed. The fluctuations of level in Lake Bonneville Avere rec^orded principally by beaches and embankments of mechanical origin : similar changes in Lake liahontiiU arc made known by tuf.t deposits of chenucal origin. The tufa of the J^ahontan basin i)resents three main varieties, each of which is composed of concentric layers as is shown in Plate 21. The smallisr divisions seem to indicate minor changes in the chemistry, anottoms and still wholly or in part submerged. The islands in Pyramid lake are sheatlied from base to summit with tliese deposits and their precnpitous sides g-ven a convex outline, owing especially to the vast de})osit8 of Dendriiic tufa, which was precipitated most abundantly midway uj) the slopes. The most remarkable of these islands, and the one fiom which the lake derives its name, is shown in the sketch forming Plate 23. When the uifa towel's and castle-like piles are broken, the concentric layers of which they are composed are revealed and fill one with wonder at the vast imoiint of material they contain, as well an attract the eye on account of the flelicacy 11:> LAKKS OF NOItTH AMERICA. : It ill and boiuity of tln'ir striu'tuii'. Xowlicii' t'lsc in this country, and so far us ii'i)ort('(l, nonlion* else in tlic world, are roeks formed of preeipitates from lake wateis so maj^nilieenlly displayed as in tin; desert valleys of Mevada. The fascination of the weird and frecpiently wonderfully impressive sceneiy of the rejrion formerly suhmern't'd beneath the waters of Lake Lahontan, is enhanced, at least to the jreolojiist, by the fact that there is yet an unsolved mystery eonneeted with the tufa deposits that start out as strano'e, ^iountic forms from the desert haze, as one slowly traverses those bitter, alkaline lands. It is believed that we understand how the more compact and stone- like variety of tufa was deposited, since similar accutnulations are formeil where waters saturated with calcium cmbonate deposit that salt on account of the loss of carbonie acid. The Dendritic tufa may also have been pre- ei[)itated in a similar manner, or perhaps through the ageuey of low forms of [dant life. The mode of origin of the tufa with well-detined crystals, howcvei', is still unknown, although both geol(\gists and chemists have sought diligently to discover tha secret of its formation. The oi)en cellu- lar structure of the crystals, as well as their fcu'ms, suggest that they aiv l)seudomor[)hs, that is, having a false form, or a form not assumed by cal- cium carbonate on crystallizing, but resulting from the iilteration or replacement of some other mineral. This suggestion only removes the dilUculty tme step farther, however, since the nature of *he original min- eral is still unknown. A more detinite statement of t'lis problem may be found in a special repo)'t on Thinolite, by E. S. Dima, who has [)ut the matter in a (dearer light than had [)reviously been d.)ne.^ One of the most I'cmarkable facts in connection with the history of the Lahontan basin, is that the present lakes within it, which might be sup- posed to be renmants of the ancient water-body left by inconiidete evap- oration, and th:'refore intensely saline, are in reality scarcely more thiui brackish. As shown ii the table of analyses of saline lakes given on page 7:2. i'yramid, Winnenuicca, and Walker lakes, the representative water boilies now existing in the Lahontan basin, carry oidy a small frac- tion of one per cent of saline matter in solution. We know that Lake Lahontan did not overllow. All of the saline matter carried into it, therefore, nuist still be retained in its basin. The vast quantity of vari- ous salts, and espet-ially of sodium chloride, sodium sulphate, and sodium ' ■■ ("lystallogriiiilik' Stiuly of the Thinolite of Lake Lahontan, "' Bulletin No. 12, U. S. Cleol. Suivev. I so far lU'VS of pressive )t' Lake there is tart out vaverses tl stoiie- ! formed account )eeu pre- )W forms crystals, ists have HMi eellu- they are il hy eal- iilion or (tves tl le liiial min- II may 1k' 1 lUt tl le rv o f th t 1 )0 s up 'U' evap- than lore i-iveii on tentative iiall frae- lia ivt' t Lai into it. of vari- ll sodium X ■< X 3 1-' i; lUilililc :. CO CO UJ O o CO O z o X CO <~ Q < > UJ CO O z cc a. CO CO z I- < < O < u. .3 H Jiiililjiiiiiiiiiiiiillililiiii STUDIES OF SPECIAL LACIJSTRAL HISTORY. 113 carbonate thus concentrated, is indicated by the weight of the calcareous tufa lining the basin. In onUnary river waters, as already shown, the calcium carbonate is about the same as the amount of all other salts in solution. It follows, therefore, that the more solnl)le salts contributed to Lake Lahontan must have been ec^ual in weight to the tufa deposits just described. Such a vast quantity of saline matter, if contained in the present lakes, would make them ccnicentrated brines. The (juestion is, what has become of the more soluble salts contributed to the waters of the ancient sea ? A lake may occasionally evaporate to dryness, or exist as a playa lake for a long })eriod, that is, expanding during rainy seasons and becoming desiccated either during dry seasons, or occasionally in years of unusual aridity. Under such conditions its contained salts would be precipitated and become buried or absorbed by mechanical sediments, so that when a change of climate permitted the existence of a perennial lake in the same basin, it would be fresh, or essentially so. This is what seems to have occurred in the Lahontan basin. The old lake was probably eva})or- ated to dryness and the precipitated salts buried beneath phiya chiys, and when a change to slightly more humid conditions permitted of the birtii of the i)resent lakes, a new cycle was begun. From analyses of the waters flowing into the present lake of the Lahontan basin, it has been estimated that under existing conditions they would acquire their present degree of salinity in about 300 years. It seems to follow from this study that during a long term of yeai-s, ending about 300 years ago, the climate of Nevada was so intensely arid that no pereiniial lakes could exist within her borders. An account of the physical and chemical histories of the ancient hdces of Utah and Nevada should be followed by a description of the plants and animals that found a home on their shores, but unfortunately our informa- tion in this connection is vague. The sediments of lakes Bonneville and Lahontan, unlike many other lake-beds, are extremely poor in vegetable fossils. A^ the conditions for the preservation of such remains were favorable, and as an extended search has failed to unearth so much as a single leaf or a single water- logged tree-trunk from their sediments, it may reasonably l)e concluded that their shores were not forested, and were probably even more barren and desolate than at the present day. Thi« result cannot be considered as surprising in A'iew of the great fluctuation of climate that the Great Basin experienced in Pleistocene times. 114 LAKES OF NOHTH AMEUICA. U'' Of the remains of vertebrates, the bones of the mastodon or mammoth, and f>f the ox, camel, and horse have l)een found in tlie sediments of Lake Laliontan, together witli a single undetermini d llsh. The bones of a nnisk-ox were obtained nea»' Salt Lake City under sueh cdnditions that it is believed they were buried in the upper strata of the lioniieville sedi- ments. The basins of e(intem[)oraneous lakes in Oregon, have yielded vertebrate fos.s.'ls more abundantly, but concerning these there are differ- ences of oi)inion as to their age. It is probable that some of them at least, aii yielded ve (liiYer- 1 at least, osits and are many luals, and •y definite available, langeable, The iuter- d avidity, lave been were per- bed to ad- of North kct. The lis extinet pund only mals, . and of a long are now iiuents of Id Lahon- 8TUD1HS OF Sl'KCIAl. LACUfSTHAL HISTORY. 116 of lakes back in 111 a Vtiat menagerie of strange and fre<|Mently gigantic forms have been made known by the labors of American j)aleiintologists. Innnediately i»rece(nng the "(Jreat (u'ological Winter," as the (ilacial epoch has l)een termed, when half of the North American continent was sheathed in ice, there was a pciiod of genial dinuite when vegetation, as varied and beantifnl as that of the Mississippi valley to-day, extended far north and leached the vicinity of the j>ole itself. I )nring different epochs in this geological summer, known as the Tertiary period, vast fresh-water hikes existccl in the Cordilleian region, several of which were fai- more extensive than any lakes now known. In some of these vasi inland seas several thousand feet of sediments were laid down. In these deposits we find in abundance the impressions of leaves lliiil wcic blown from the land, or washed in by tributary streams, and the boiu's of many large mammals, whose homes were along the lake shores and on neighboring forest-covered hills. All trace of the shore tojjography of the Tertiary lakes has disa{)- peared, and in many instances the beds of sand, clay, and volcanic dust deposited over their bottoms have been upheaved into mountain ranges, and deeply dissected by erosion. Their histories can only be deciphered from the records in their sediments. Their story y they are built. Tulare Lake in southern California has been explained by Whitney in this way. T'he contest for drainage area that goes on between streams heading on the opposite slopes of a divide sometimes produces little lakes. The victorious stream forces the divide to migrate slowly away from its steeper slope, and the stream that is thus robbed of its head waters may have its diminished volume clogged l)v the fan-deltas of side-branches farther down its valley. Heim has exjdained the lakes of the Engadiuv! in this way. The Maira has, like an Italian brigand, plundered the Inn of tw(j or more of its upper streams and the Inn is consecpiently ])onded back at San Moritz and Silvaplana. On the other hand, the victorious stream may by this sort of concpiest so greatly eidarge its volume, and thereby so (piickly cut down its tijtper valley, that its lower (,'ourse will be flooded with gravel and sand, and its weaker side-streams SUrPLEMENT. m t rivers is, luUsturbed. Ices appear has shown, load waters itors to the its t'onner Livingston, [Use valley, tter of sur- the mouM- 'fore a sign in of small middle life, in number unk-stream its smaller ther side of ver Danube ■ed streams eat curves. e as a cres- lakes often channels. suddenly d lakes on p for that : 1 in whose xplained ling on the victorious [slope, anw distinguish the cotyledons, the leaves, thv. galls, and tilt' tlowv-.'s, of a quickly growing annual that produces all these forms in appropriate order and position in the brief course of a single summer. W. M. DAVIS. CAMiiKiixiK, Mass., Septemler 7, 1887. Lakes of North Amkrica Plate 2;<. • .ii* SKETCH OF PM^AiMIL lounn u, HrHAMlu LAKE. NEVADA. \ II^DEX. Abbott, Humphreys and, Cited on rafts in Ked river, La., 27. Abert lake, Oregon, Analy.si.s of, 72. ( )rij?in of, ;i(). Aga.ssiz, Lake, Description of, 103-106. Reference to, J. Aleutian islands, Lakes on, 26. Alf;ae, I'recipitation of lune and iron by, 76, 77. Alluvial cones, Obstruction of drainage by, 6. Analysis of the waters of alkaline and saline lakes. Table of, 72. Analysis of the waters of fresh lakes, 65- 57. Great Salt lake, by E. Waller, 81. Mono lake, by T. M. Chatard, ss. St. Lawrence river, by T. S. Hunt, 60. Andrews, E., Cited (,n erosion, 60. Annie, Lake, Cal., Origin of, 10. Aqueous agencies. Lake biisins due to, 5-10. Areas of Laurentian lakes, 58. Atmospheric agencies, basins due to, 3-5. Au Train island. Gravel spit on, 48. Bars, Origin of, 47, 48. Bear-wallows, 28. Beaver dams. Lakes formed by, 27. Belleville, Out., Height of ancient beach at, 100. Bischof, G., Cited on chemistry of water, 56. Bolsena, Lago di, Ital., Mention of, 20. Bonney, T. G., Cited on rook-basins, 41. Bonneville, I^ake, Delt is in, 60. Description of, 106-109. Lakes in basin of, 20. Overflow of, .30. Borgne, Lake, La., Origin of, 8. Bracciano, Lago 'li, IlaL, Mention of, 20. Brienz, Lake, Switz.., Hefer .nee to, 7. Brighani, A. P., Cited oi; Finger lakes, N. Y., 16. Buffalo. N. v.. Rise of water at, 39. Buffalo-wallows, 28. Calderas or crater-rings, 20. Canadian river, N. M., Lava flow In cation of, 18. Carboniferous lakes. Brief notice of, 116. Cascades, Basins excavated by, 5-<5. Caspian sea, Brief account of, (iO. Ca.stani, Lake, Alaska, Origin of, 11. Catsk'll Mts., Reference to, 116. Cayuga, Lake, X. Y., Origin of, 16. Chaix hills, Alaska, Lakes near, 11, 12. Chaniplain, Lake, Terraced borders of, 02. Chatard, 'J\ M., Analysis of the water of Mono lake by, 88. Cited on aiuilysis of lake water, 72. Chelan City, \Va.sh., Mention of, '">♦!. Chelan, Lake, Wash., Description of, 65-(i9. Chemical action, Basins due to, 31, 32. Chemistry of lake waters, 56-60, 60-77, 81-88. Chicago, 111., Rise of water at, 34. Cinder Cone, Cal., Lakes near, 18. Cleveland, ()., Erosion near, 61. Climati', Influence of, on lakes, 37, 38. Climatic conditions. Relation of, to lakes, 64. Coast Survey, U. S. , Chavts of, 9. Cochituate, L.ake, Mass., Origin of, 17. Color, Trevailing, of lake beds, 41. Columbia river, Wash., Lakes in old channel of, 6, 6. Commerce of tlie Laurentian lakes, 61, 62. Como, Lake, Ital., Meniiim of, 15, 64. Com.stock, v\ B., Cited on Lake Survey, 67. Coon butle, Ariz., Description of, 21, 2'?.. Crater lake. Ore., Description of, 20, 21. Mention of, 64. Crator lakes, Origin of, 10. Crosman, C, Records of erosion, by, 60. Crolon river, N. Y., Soluble matter in, 56. Currents, Wavei and, in lakes, 33, 34. Dana, E. S., Cited on thiiiolitic tufa, 112. Dana, Mt., Cal., View from, K4, 85. 122 INDEX. pi m Davis, W. M., Cited on classification of lalvcs, 1, 117-120. Cited on crater lakes, 19. • Cited on lakes of Ked river, 8. Cited on lakes retained by deltas, 7. Dawson, .J. W., Cited on carboniferous fos- sils, 115. - — Cited on Pleistocene history of Lauren- tian basin, 102. Dawson, \V. M.. Cited on Lake Yukon, 17. Delta in Lake St. Clair, Origin of, -10. Deltas, Formation and structure of, 48-01. Deltas, Lakes on, 8. Dendritic tufa, Origin of, 110. Detroit river. Area, water-shed, etc., of, 68. Diastropliisni, Lakes due to, 28-:Jl. Diatoniaceous earth, Origin )f, 42. Dieulafait, M., Cited on precipitation of salts, 74. Diller, J. S., Cited on lakes in Cat., 18. Dirt glacier, Ala.ska, Lake retained by, 11. Druniiiiond Inke, Va., Origin of, 26. Dunes retaining lakes, 4. ■atton, C. E., Cited on Crater lake. Ore., 20. Sarttiquakes, Bai^ms due to, 25, 26. En'^. Lake, Currents i M. Bfccts of CJtl*' 'ii ;4. Biwsitm of the shores of, 61. Ifmlmnkineiits, ( >rigin of, 46-48. ■■■HI of laks shores. 60. fltaiik-ba^DS, Description of, 20, 30. Heference to, 2. Finger laktw, N. Y., Origin of, 16. Fisheries of the Laurentian lakes, 62. >1orida. Lakis on new land in, 1. Flow of streams, Influence of lakes on, 88, 39. Fort Bidwell, Cal., Lake Annie, near, 10. Fossils in sediments of lakes Bonneville and Lahontan, 114. Gaylussite, formation of, in Soda lakes, Nev., 73, 74. G«neva, Lake, Switz., Delta in, 91. Purity of water in, 40. Gilbert, G. K., Citel cm age of Great Salt lake, 82. Cited on Cn.,n hntfH. Ariz.. 21, 22, 24. Cited on ice-walls. .v>. 53. Cited on Lake Bonneville, 106. Gilbert, G. K., Cited on lake in Ice Spring butte, Utah, 19. Cited on lunar craters, 24, 25. Cited on Pleistocene history of Lauren- tian basin, 9(1. Cited on wind-erosion basins, 3. Glacial agencies, Lakes due to, 10-17. Cilaciers, Lakes on, 10, 11. (Jlen Hoy, Scotland, Ancient beaches in, 12. Grand Coulee, Wash., Lakes in, 5. Great Basin, Origin of lakes in, 2. Pleistocene lakes of, 106-114. Great lakes, Plei.stocene history of, 00-103. (Jreat Plain of the Columbia, lakes on, 4, 5-6. Great Salt lake, Utah, Analysis of, 72. Description of, 77-83. Precipitation of sodium sulphate in, 75. See also Laurentian lakes. Gustavila, Lake, Mex., Mention of, 20. Gypsum, Bjisins due to solution of, 32. Hamilton, Ont., Height of ancient beach at, 100. Ilayden, F. V., Cited on Twin lakes, Col., 14. Hayes, C. VV., Cited on lakes in \la.ska, 17. Hudson river, N. Y., Soluble matter in, 56. Hull, E., Cited on Laacher See, 10. Ilumlioldt lake, Nev., Analysis of, 72. Origin of, 10. Humphreys and Abbott, Cited on rafts in Red river. La., 27. Hunt, T. S., Analysis of water of Si. Law- rence by, 60. Huron, I>ake, Area, depth, eic, of, 58, 50. Currents in, -34. Ice-lniilt walls, Origin of, 51-53. Ice Spring butte, Utah, Lake in, 10. Inland Salt Co., Utah, Operations of, 82. Iroquois, Lake, Brief account of, 99. Judd, J. W., Cited on Caldenis, 20. King, C, Cited on Lake Lalumtan, 106. Cited on thinolite, 110. Klamath lake, (hv., Mention of, 20. Krakatoa, Eruption of, 21. LaaohtT Set , Germany. Mention of 19. Ijiiontan, Lake, Nev., Description of, 106- 114. e Spring ; Lauren- ;i. 17. les in, 12. 96-103. )n, 4, 6-6. E, 72. ate in, 76. ■; 20. , 32. ent beach 8, Col., 14. \laska, 17. lev in, 56. I. 2. rafts in !^. Law- 08, 50. ^f, 82. 106. INDEX. 128 IP. of, 106- Lahontan, Lakes in basin of, 10, 20. Lake Survey, U. S., Cliarts of, 0, 48, 40. Tides observed by, 33. Work of, 57, 58. Land slide.s, Basin formed by, 31. Laurentian basin, I'leistocene history of, 00- 103. Laurentian lakes. Account of, 57- Areas of, 58. ("olor of clays in, 41. Currents in, 33, 34. Krosion of the shores of, 00. See also Great lakes. Lawson, A. C, Cited on I'leistocene history of Laurentian basin, 96, KKt. Le Conte, .John, Cited on Lake Tahoe, 64. Ob-servations by, in Lake Tahoe, Cal. — Nev., 35-.']7. Life histories of lakes, 90-95. Lithoid tufa. Origin of, 110. Lockyer, N., Cited on meteoric bypotiaesis, 24. Loe.ss, Origin 01. 11. Logan, Utah, Delta near. iO. Loniis lake, India, l^scnijution of, 2H. Lyell, C. Cited 00 raft* in lied river. La., 27. Maggiore, Lake, Ital., Mention of, 64. Reference to, 15. Malaspina glacier, Lakes near, ft, lil. Manitoba, L.akes in, 7. Manitou island, Lake Michigan, Sea cliff on, 42. Miirjelen lake, Switz. . ( )rigin of, 1 1 . Mechanical .sediments, Deposition of, 41. McGee, W. .!., Cited on New Madrid earth- quake, 25. Meteoric hypothesis. Reference to, 24. Meteors, Basins due to impact of, 24, 23. Michigan, Lake, Area, depth, etc., of, 58, 59. Currents in, 34. ■ Kffects of gale on, 34. KroH'on of the shores of, 60, 61. Influence of, on climate, 38. Mississippi delta, "Mud lumps" on, 28. Mississippi river. Soluble matter in, 56. Mono lake, t^al., Analysis of, 72, 88. Crater- lake in. 19. Description of, 83-89. Lake on island in, 24. Moraine lakes near, 14. Mono Lake, Cal., Recent fault near, 30. Tufa bowl near, 32. Moon, Origin of craters on, 24. Mora river, X. M., Lava flow in cafionof, 18. Moses lake. Wash., Origin of, 4. Mountain lakes. Examples of, 63-09. Muir, J., Cited on lake in Stikine valley, Alaska, 11. New land areas, lakes on, 1-3. New Madrid earthquake, Lakes formed by, 25. Niagara river, Area, water-shed, etc., of, 58. Newberry, .1. S., Cited on lakes in coal swamp.s, 115. Oldlinm. K. I)., Cited on Lon.is lake, Ind., 23. Ontario. I^ke, Area, depth, etc., of, 58, 59. - - Currents in. 34. Oiilitic suiiiid. Origin of, 77. Organic agencies, BHsins due to, 26-28. Ow»-iiK lake, Cal., Analysis of, 72. Ox-tJijw lakes. < »righi 1 '1, 8. Parks of ('oif»rado. Origin of, 15. Peat bogs, Dramttige of, 42. Pepin, Lake, Origin of, 7. Perkins, K. A., Cited on Seiches, 35. Play a lakes. Origin of. 70, 71. Pleistocem iake-beds. Coh)r of, 41. Poe, O. M. L<\M*- mtrw-ys by, 58. Pontchartraui. Lake, La., Origin of, 8. Powell, J. \^' . Cited 00 (^structions in Colo- rado river. 7 Precipitates troni saline iaiites, 71-77. Pyramid lake, Nev., Analynas of, 72. Rain-fall -a Lauivntian basin. '>9. RajEtown, Xev., Salts formed in lakes near, 73. See a,\m> Soda lakes. Samsay, A. C, Cited on rock-basins, 15. Bed river. La., Lakes on, 8. Timber rafts in, 27. Rhone, Delta of , 91. Kock-basins maile by glaciers, 13, 14. Rock-basins, Origin of, 4. Roth, J., Cited on chemistry of water, 55. Rothplitz, A., Cited on oolitic sand, 77. Rush, Lake, Utah, < >rigin of. 9, 10. Russell, Tnomas, Cited on evaporation, 59. 124 INDEX. St. Clair, Lake, Area, water-shed, etc., of, 68. Delta formed in, 40. St. Clair river, Area, water-shed, etc., of, 58. St. Lawrence basin. Rain fall in, 59. St. Lawrence river, Analysis of, CO. Volume of, 58. St. Mary's river. Area, water-shed, etc., of, 68. St. Mary's river. Rise of water in, .34, 39. Saline lakes, De.', 7. t beach at, Dtained by, 1,4. 52. fisheries of Agassiz, 7, }ochituate, 7-24. lage by, 4. 15. jreat Salt _aVimenta/ r^ nomm: bldg. ^^^ ^ JM 2 4 ?^ .<^^ .^