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I>l. MK VII. V SKETCHMAP ^ Of - \ PART OF ONTARIO. l(i sy f a. TAYLOR. L A \>^ BAY > dL\ LIMIT OBSERtftC _a> Cl/VJfCTUH»>l- Be DK.J.VV SPENCER o- LIMIT OF POSTGLACIAL SUEIVIERGENCE EAST OF GEORGIAN BAY. f From THE LIIS THE I Tho rej; west end ( •fiaii bay t some prel which do : t'xpU)ratio Most of tl was accoii previous t (describi'( Gkologist xVdirondai ex|)lorcd i^ liiirrie. Allandale, ( n)r. J.'' eastern pn of the h)t til is form eoiirt iiou changes ti of a mile high, nan ■*"I)t'!ori Am. .loiii'. ! mmmmrmmmi^ \Fri)iii T/it: Amiriritn Oeolnffint. V»L XIV, Xnrniifxr, 1S94.'\ THE LIMIT OF POSTGLACIAL SUBMERGENCE IN THE HIGHLANDS EAST OF GEORGIAN BAY. liy !•. 15. Tayi.ok, I'ort Wayne, liid. (Tlate VII.) Tho region described in tiiis paper extends from the south- west end of lake Sinieoe throuj^h the hijrlilands (tast of Geor- eacli ridge and projects alxnit an eighth of a mile westward along the north side of Collier street as a high, narrow spit. This spit is in the old part of the town, * "IK'Sormation of tlie Al^'iiiKiiiin Mi'itcli. iiixl Birth of r.ukc Huron." Am. .lour. Sci., Ill, vol. .vm, pj). \.l-2\, willi miqi. .Ian., 18iH. 274 Tin: Aiiicr/rdii Gcolotjint, November, 1894 ntid is ('(tvcrcd witli li.tuscfi. Two cluirclu'S arc also built upon it. In Honu' i)laffs it 'uis \n-vn cut away, but it continues iis a prominent feature as far as Clopperton street. VVIiere excavations iuive be. n made the composition (tf tiie ridf^e is siiown to l)e ol" characteristic lieach material, — rounded f^ravel and pebbles with sand. Near its outer end this ridj,'e is alxnit 2(» leet above the },'eneral level ol" the town. The altitude of hike Sinicoe is stated l)y Dr. Spencer to lie 722 feet above sea level. The shore line in Harrie, nu'asured on the beach ridji;e where it is crossed in the eastern part of the town by the l\'netan}ruishene road, is about (iO feet above lake Siin- coe, or approxinuitely 780 feet above the sea. Westward from the si)it the {ground is lower aiul for sonu^ dis- tance west of the town it is a rolling sand plain. Hetween liarrie and Allandale there is a low trough extending west- ward from the lake. Along the base of the hill south anil west of Allandale the beach was found rather lightly devel- oped. We ascended the first point of the hill on the ('o(.ks- town road, from which a wide view over the surrounding lowlands was obtained. Toward the west in the troiigh, whicii divides the highlands of the north from those on the south, the extension (»f the beacii could i)e seen for a milt- or more; but whether the water at ihe time of submergence ex- tended clear through the trough to Colwell so as co make an island of the highlands north of it, was not seen. Eastward from Barrie the shoreline was found beautifully developed all the way to Orillia. Jt may 1)e seen plainly from the train nearly all tiie way. Just east of Harrie the railroad cuts the beach, nuiking a fine cross-section, and then rises to a higher level for a few miles, leaving the i)each between it and the lake. Tiirougli this stretch it is ii iiiu'ly formed gravel ridge with a lagoon hollow behind it. In some places there are several lower ridges with intervening h.ollows. But beyoiul that, for most of the way to Orillia, it is a cut terrace with a low blulf at its back and a gentle boulder slope in front. It is well formed at Oro and Ilawkstone. Within a few miles ..i Orillia the beach passes out of sight in a forest. Orillia. Along the face of the high blutf buck of this place the shore line was found clearly developed as a cut terrace with a few beach ridges at lower levels. It is particularly PiiMffihirifii SiihiiHi'ficiine cnsf of (iejDUildii fini/. — Tinilor. 27R well iiuirkocl jiiflt above the imiin rmul Tor two or tlircc mik's r.ortli of till! town. It in iiciirly as itroiniiu'ii* in the town itscli', ui!'.' niiiy !><• >*«'cn to j^ood iKlvantn^c on West, ('oldwatcr and I'cnctanfi (Ui-i-cts, and in Kcvi-ral otlicr piaceH. Toward tiie soutli tile ancient coast line heconicrt deeply indented hy a valley, and into tliif the nhore line ^radtialiy fadcH away. Diiriiif; the second visit to this place \ drove to McDon- ald's hill, about two miles northeast oT Atlierly, a v. age which is about two miles east of Orillia, on the opjjosite side (if the river. This hill is about 85 feet above the lake and its crest, wliicli is a wide, bouldery bea-h ri(lge, evtends in a northeast and southwest direction, and ai)pears to have l)een heavily washed by waves. Extensive excavations have been opened in the western slope of the hill near its top for ballast, and thfy show its composition to be almost entirely of lime- stoiu' bould'Ts of small size, and jjradinff from this down to the iineness of c(>arse sand. The (juantity of small boulders or cobbles of a diameter avera}j;ing from four to eij^lit inches is enormous. All the material is thoroughly rounde('. Tliehill faces northwestward over lake < :ouclii<*h'c" and ^lie valley of '11 is not ipiite ■ is MO liindy plain. The upper terraces arecomixtsed mainly of pretty coarse nuiterial. Farther on, tlie hill east of I'eiie- tanji'uishene rises about to the level of the shore line observed south of Midland, i)ut we did not succeed in lindin^' the beach on tlu south slope, which was the only ••id«' v.-e examined. From the upper edge of the town lookinr. 277 f ftccti, liowtvcr, whifli wotild tend t<» esuihlisli tlir t'nct of Huli- The villiijjt* of I'arrv Soutnl iw l);illt iipoti ii ^rnvolly ildtit (U'poHit wliicli Ih iihoiit 50 feet alxivc tln' sound. Actohh th« river I iiHcciidcd tlie rufj^cd lull hiick of I'lirrv Iliirhor to iin iiltitiKlf of about i.")!) IV-ct. liut found no distinct cvidcncf of iio«t|?iH('inl Huhnicrf^cnct'. Our t'xplonitlon, hrtwevor. was too limited at tliis placo to jjjixo mucii vuluo to tliiw nef^ativc result.* From I'arry Soutul wi- went hy stajje IH mileH across the counti'^ to Port ('ockl)un!, at the iu-ad of lake -Joseph. At two or three places evidences of j^eneral submergence were seen. On the west side of Horseshoe lake, there are some ter- races whi'-h are evidently the j»roduct of wave action. They were about (50 feet 'tbove the lake, and aboufilO feet above Georgian ba}'. About the head of lake Joseph tlure are some suggestive features about 50 feet above its surface, but ■ one that were distinct and clear. Nor weie any noticed ^;u trip down lakes ,Iose|)h and Muskoka. (tri'rciifiitrsf. At this place our time was too short to ad- mit of thorougli examination. In the ui)per part ol the vil- lage, however, there is a wide sandy and gravelly ridge v.'hich faces westward over Muskoka la' and is undoubtedly in pait the work of waves. IJut we did not see any evidence v.hich siiowed whether it is the highest ritlge or not. Its altitude is alxiut M25 feet above sea level. In going northward by train we saw abundant evidence of submergence within two to four miles, at levels ?.") to 100 feet higher, but the up])er limit wis not distinctly nuide out. liriK'thrid'je. At this place we found nuigniiicent remains of the great submergence. They are of two kinds : one is the product of wave action, and the other of still-water dejjosi- tion. rhe latter, especially, is lUveloped on a grand scale. The beaches are clearly deliiied, and the still-water sediments are iine-bedded or laminated silts and clays in horizontal lay- ers, forming a deposit 7r> to 100 feet thick. Taking the main ro'd northeast f"-om liracebridge we crossed tlie river just below the station and climbed the steep ascent of the east bank to the surface of a sandj' plain. Within *1 liii-c since Iciiriii'd llint M;. ( iilhri't liad visilcd I'jii'ry SdimkI iiiid found liTi'iK'i's wliicli wi' did not sim-. 278 The American Geohxjist. November, 1894 H mile, dir js jind sandy ridges bef^an to appear. One of these, in a field about 40 rods cast of the road, is a long and very evenly formed bcaeh ridge. Farther to thenorthcist the road crosses a few faint ridges and then ascends a series of three or four low gravelly terraces, which face like steps toward the southwest over the sandy plain. The first road to the right, which follows the seventh and eighth concession line of Ma- caulay township, leads across a scries of ridges of gneiss, with intervening hollows of considerable depth. Across these we drove about three miles to an abandoned farm which ap- peared to l)e near the top of a fifth principal ridge. On the east side of the first ridge and near its top there is a large terrace of water-worn gravel and pebbles. Its composition is well shown in a ballast pit. At the top of the third riilge, whicii is about two and a half miles northeast of Bracebridge, the most marked evidences of wave action were found. The crest of this ridge is Hanked on both sides by gravel terraces. The one on the east is snuill and narrow, and the ground is not well cleared for observation, but the one on the west is much heavier anil easier to see. In a lot just south of the road it has tlic form of a wide, low ridge with a slight depres- sion behind it. North of the road the terrace extends at ab. ut the same widtii, and the farm l)uildings of ]Mr. Leeder are built upon it. From tiie field soutii of tlu> roail the ter- race e.\t<'nds southward as a slu)rt spit ridge, forming a ('(ui- nection \vith a rocky ledge, which was formerly a reef with water off its precipitous front (U) to 70 feetdeei Excavations for postholes show the composition of the spit and the terrace in the field to be characteristic beach gravel. This terrace faces southwest over the valley of the ^Nluskoka river, and Muskoka lake and Georgian h'^y. Its altitude is about 975 feet above sea level. In passing over the otiier ridges to the eastward wc did not discovcu' any evidence of submergence at higher levels. The second ridge, whicli lies next west of the third, is not so high and did not record the ui)per limit of wave action. The first ridge lacks only 2U or 25 feet of i)eing as high as the third tine, but we saw nothing to show whetlier the terrace on its east side nuirks the highest level of submer- gence or not. Looking eastward from the top of the second ridge, the terrace at Leeder's farm, on tiie third, is seen to ., i Postylacial Sabmou/cncc east of Geonjian hay. — Taijlor. 279 extt-nd in a great curve arnuiul to the north and join the sec- ond. From the first ridge the long level of the terrace extend- ing for two or three nules to the north is plainly seen. Returning to the lower ground, we found that the sandy plain whici. forms the banks of the river at liracebridge is the top of a great deposit of silt and clay, and that the town itself is situated upon an eroded slope of this great bed. Several excavations in the streets showed its character very well. The banks along the river are steep and, below the falls, 90 to 100 feet high. In some i)laces this whole depth is composed of the laminated beds. It is plain tlmt the extent of this deposit was once considerably greater than now, for the numerous deep ravines which have been cutinto it since the recession of the water show how much has been removed. We drove also about seven miles soutiieast, past the falls of the south branch of the Muskoka river, to a point about two miles above. For the first mile the road is over the deeply gullied surface of the silt plain. Then the road passes over a hill, at an altitude of about 90 feet above the railroad sta- tion, and on the top of this hill are several well formed beach ridges of water- worn gravel with depressions between them. Beyond this the road descends through a very deep and steep- sided valley which has been cut out of the silt by a small stream. Both sides show the laminated fine sediments to a depth of over 100 feet. The beaches mentioned are on the top of the north bank, and the contact between them aiul the silt may be seen in the ditch l)y the roadside. Between this gully and South falls the ro.'ul passes over some higherground which is pretty heavily covered with dune sand, and is at about the same level as the sandy tract northeast of Bracebridge, but considerably below the highest beach. From Bracebridge to Muskoka hike, the Muskoka river is a navigable stream Mowing with a sluggish current through a great expanse of swampy fiats. After the maximum sub- mergence, during which the upper part of the former estuary of the Muskoka was filled witii the silts and clays, the reces- sion of the waters was accompanied by a restored activity of the river, which then commenced the re-excavation of its bed. We have in conse(iuence the level plain of the silts at Brace- bridge cut by the narrow, deep gorges of the river and of sev- 280 The American Geologist. November, 1894 eral cret-kss, and belmv, toward the lake, the wide Hats built up larfi;ely with the silt brought down from above. J/itiif,sn'l/e. As it passes northward from Hracebridge the railroad climbs up out of the gorge of theMuskoka river, and toward Iluntsville passes over ground mostly at or near the level of the beaeh at liracebridge. At h'jveral points heavy deposits of water-worn gravel and pebbles are crossed. At its highest point the railroad appeared to jjass somewhat above the level of these sediments. But on the descent toward Iluntsville the gravels are particularl}'- conspicuous, choking up the beds of all the small streams and forming long, narrow grevel plains. At several points these deposits have been excavated for ballast. At Huntsville station the evidence o+" postglacial submergence is very clear, although it is not strongly developed. The station is on the east shore of an arm of Vernon lake and its altitude above the sea is 960 feet. A steep hill rises back of the station to a hight of over 350 feet, and along the base of this hill, almost within a stone's throw of the station, the highest shore line is sharply and clearly marked as a cut terrace. Its altitude above the sta- tion is about 40 feet. For over half a mile along the western face of this hill the shore line is plain and continuous, and it was easily recognized for about a mile farther each way. At the back of the terrace the old blutf rises ten or fifteen feet more steeply than the general slope of the hill above. I cliiubed to the top of the hill, darting up opposite Cook's ho- tel, and reached a point over ;U)0 feet above the shore line, but saw no further evidence of submergence. The top of this hill commanils a grand view over most\)f the country around. Sev- eral lakes are in sight at once, Vernon lake toward the north- west. Fairy lake antl Peninsula lake toward the east; lake Mary toward the southwest was not in sight, but the water from the other lakes passes down through it and the north branch of the Muskoka river to Iiracel)ridg(.'. The shore line at Huntsville is not in a place exposed to a wide sweep of waters like Georgian ba}^ init marks the shore of a former sound or long inlet, which reached from the inland valleys to the open water at liracebridge. The valley is wide and open all the wa}' from the head of Vernon lake. Steamers ply from Ilunts- ville to all these lakes, and by a portage of less than a mile 1 Posf(/l(tcuil Siibmeryence east of Georgian hay. — Taiflor. 281 I they connect with tlio Lake of Bays, which empties into the south branch of the Muskoka river and formed another of the many ancient inlets of this region. The fine bedded silts were found at several places in Huntsville close up to the level of the beach. I have no doubt that this shore line is a part of the highest beach of postglacial submergence and is one with the main beach on the more exposed coast outside. J{itrk''s Falls. Our observations at this place were some- what disappointing. We failed to find any distinct beach which might mark the upper limit of submergence. Probably this was because of misinformation with regard to the proper roads to take to reach favorable high ground. Many inter- esting remains of submergence, however, were observed, nearly all of them belonging to the fine sediment class. The laminated silts and clays of Bracebridge are in some respects e(}ualled, if not excelled, by those at Burk's Falls, where also they at- tain a depth of about 100 feet. The Maganetawan river has cut a deep ravine through the silt bed, and its little tributa- ries have cut numerous gullies in the remaining mass. The general a,.pearance of the formation is the same as at Brace- bridge. We drove about three miles and a half southeast of Burk's Falls to a point on the hills near Katrine. The cleared farms of that vicinity are mostly on the gullied surface of the silt deposit. At one point the road rises to a level of about 135 feet above the station and cuts a bed of water-worn gravel which may be related to the submergence, but we saw nothing which would establish that fact. Between the village and the station gravel beds were observed in two places resting on the top of the silt. One of these is south of the road near the Presbyterian church, the other is on the opposite side near the top of a low hill. It seems probable that these gravels mark a level not more than 30 or 40 feet below the maximum hight of water during submergence. We also drove about four miles west from the village to an old winter ford of the Ma- ganetawan. The road is mostly at lower levels, and, for the first mile or two, crosses the gullied surface of the silt. Some interesting sections of the deposit were seen here with the laminations beautifully displayed and in several places very much disturbed by faults and folds, which appear to be due to landslides and slippings on the steep sides of the gullies. 282 The American Geoloyint, November, 1891 The hills about liurk's Falls are high, and if the submergence attained the higlit whicli seems to be indicated by the depos- its, the ancient ciiannels were deep, and varied in width from a half mile to three or four miles. Dr. Spencer puts the alti- tude of the submergence at this place conjecturally at 1,171 feet. Steamers run from Burk's Falls to Ahmic Harbor, 40 miles west, down tiie Maganeta\van, but our limited time did not permit this trip. Sunih'idiie. This place is situated on the north shore of Stony lake, which empties through Stony creek towards the southwest into the Maganetawan river. The lake is five or six miles wide, and it fills only part of the trough in which it lies. Near the station there are several light terraces and beach ridges of sandy composition; and about a half a mile north there is a heavy glacial ridge, on the south side of wliich is a tolerably distinct slun-e line at about 100 feet above the station. On the slope below are several distinct terraces. This beach, like that at ITuntsville, might be supposed to be of local origin, but it is also on one of those long inlets which connected witii the wider water outside. f>oiif/i Ji'ifc.r. At this place we have crossed the divide to the region of the streams which descended the steep slope northward to lake Nipissing. Part of the drive from Sund- ridge was entirely al)()ve tiie level of the beaches of this vicinity and over unmodified drift. About a mile west of South River a distinct cut terrace was crossed at the foot of a steep hill. Hut it was so obscured by a heavy forest growth that the character of the ground in that vicinity could not be seen to advantage. There ai)i)eared to be a gradual slope, about a quarter of a mile witle, with occasional boulders and an appearance of low ridges. At its edge the road comes out upon a sand plain with dunes, and then descends through the ravine of a small stream. In this ravine the fine-bedded silts and clays again api)ear, and fiom this place to the town, half a mile distant, the road passes over the surface of a level sandy plain. Measured from the station at Soutii liiver the altitude of the <'ut terrace is about 1.220 feet above seii leveL At another point, about two miles south of South River, two terraces are found on a sandy hillside at altitudes of about 1,190 and 1,195 feet above the station, and on another isolated » I- Post()lucial Suhmeryencc east of Georyunt huy"^ — Tujihir. 283 hilhitan altitude of abcut 1,215 feet. From the top.of this? last hill there is a wide view over the surrounding country and it could be seen that the Hats at South River are continuous througii to Stony lake, and they also extend a long way east- ward up the valley of South river. In that direction the hills bordering the flats appeared to be terraced at 50 or 60 feet above the flats, agreeing closely with the level of the shore line west of South River station. Half a mile north of the station are Dununr's falls, where the river was diverted to one side of its former valley and thrown upon a rocky ledge. From this it falls more than 100 feet and has excavated a deep ravine towards the north. It is apparently certain that the whole sandy plain at South River is the surface of a great silt bed. At a point about three miles north of South River the railroad crosses a marsh about two miles wide. This is the top of the grade of the railroad, and its altitude on the profile is given as 1,202 feet. The west side of the swamp is bounded by a great gravel ridge, which looked from the distance like a beach, but which, on close examination, proved to be a glacial moraine. Its summit rises about 80 -r 90 feet above the marsh, is very uneven and covered with m.ny pits and hollows. It has been excavated for ballast by th* railroad, showing it to be com- posed of all grades of material from line sand to large boul- ders. About half a mile north of the gravel pit the moraine slopes rapidly northward down into the deep ravine of South river, and looking from tiie edge there may be seen at a distance of three or four miles to the north a very conspicuous shelf which appears as a long horizontal line extending along tlie east side. This shelf is very close to the level of the beach at South River, and I have no doubt that it represents the highest line of submergence. It was near the mouth of the ravine and was exposed to the northwest over lake Nii)issing. Trout, Creek. The high terrace just mentioned must be close to the station of Trout Creek, probably within a mile or two to the south, but it did not appear to be accessible in the short time at our disposal. Our eit'orts to explore the vicin- ity of this place were rather unfortunate. We arrived only a little before dark and it began to rain immediately. We drove westward about two miles over a sandy j.liiir. to the bridge over South river, where we found a fresh excavation in the i' ¥in m ' "' " y 284 The American Geohxjist. November, 1894 high bank on the east side, which showed a splendid section oF the fine-hedded silts and indicated that the whole plain over which we had passed is of that composition. There are also several dunes on the plain. Southeast of the station along the base of the hill there is a cut terrace about 20 feet al)ove the flats. The flats themselver? extend about two miles southward to the south end of the long trestle. They are ap- parently perfectly" level, and just under the south end of the trestle there is a terrace in the same relation to them as that near the station, and it is probably a continuation of the same. In September, when I revisited Trout Creek alone, it rained harder than before; but I walked half a mile up the hill to the east and reached a point about 110 feet above the level of the station. At that place there appeared to be a sort of shelf facing the northwest and covered with a great nuni])er of boulders of large size. There were so many of them five to six feet or more in diameter that the road had to be crooked about to find a way among them. Tlie altitude of this place is about 1,145 feet above the sea. On the basis of the obser- vations at Sundridge and South River the boulders on the hillside are probat)ly somewhat less than 100 feet below the level of the highest beach. Considering the very exposed position of tliis hillside, I should expect to find the highest beach slrongly developed. From this point the hills at the supposeil hight of the shore line extend slightly north (sf east to the valley of the Ottawa river and also toward the west- southwest 30 or 40 miles. Pawassan, seven miles north of Trout Creek and about 17') feet lower, is also an interesting localit}'. Besides fragmentary beach ridges of gravel, the silt beds are extensivelj' developed and lie apparently in a more exposed position than usual. Of the other localities far- ther north, which were visited on these excursions, a separate account has been given in r.novher article,* which is virtually a continiuition of this although it was earlier in publication. *"Tlic Ancii'iit Strait ut Nipissinjr." l?iilli'tin, ficol. Soc. of America. Mil. V, pp. ()'20-()2('), with maps. Api'il :!(), I.SIM. Mi'iilioii sliDiild liavf l)fi'ii made ill this jiaiH'!' of tiu- i'act liiat I'rot'. (i. Frederick Wriiriil and jiarty. iiieludiiii;- Prof. A. A. Wri;rht. visited some of the irravel pits I'ast of ('artier in llie autumn of W.n. See Prof. (i. F. Wi'ijilil's jLiper, ••'I'lie Siii)i)()sed Postiflaeial Outlet of the (ireat Lakes thronirh liake Nijiissiii'; and the Maltawa River," ISulletin. (ieol. Soc. Amer., vol. iv, PI). 4'i:t-."). with Dr. Uoherl Hell's remarks in discu'^sion, pp. 42.")-7. iN^ Postylacial Submeryence east of Geortjiun hay. — Taylor. 285 The highest shore line was fouiul on the hills rorth t)f North Bay at an altitude of about 1,140 i'eet above the sea level, and again eigiit miles east of Cartier on the Canadian Paeifie rail- way at about 1,200 feet. Slmmauy and Conclusions. The altitudes of the beaches observed are summarized in the following table. The measurements were all made by aneroid from points of known altitude near by. The letter r stands for hearh n'dye and the letter t for terrace. I'.arric '' "'<•' Ldiiicvill.- / ■'^l'> Orilliii ' ''^^i** Mi.llM.ul / ^-^^ Oi'iivc 11 hurst '" S2^)-|- .' liraccbriil'iL' /• '•"' Hmitsvill.' f 1.""" IJtirk's Falls (Spt'iicr) I.ITI r Siiiiilndfit; r l.-i<'"' •South Riv.-r t I--" TniiH CiMM'k / 1.14.-)+ ? Niivth Itiiv (Hi Nelson's) r l.HO Carti.T ■ t 1.300 The facts show clearly that the same water that filled the ancient channels in the southern highlands extended far to the north and west. It evidently covered all the lowlands of this region and, as indicated by tiie altitude of the shore line, made a strait over lake iS'ipissing at least 25 miles wide and 500 feet deep, and probably another farther north over the hight of land to Hudson bay. There is also much reason for supposing its extension ilown the Ottawa valley to the lower plains of Ontario and the area of well established iiuirine sub- mergence. But it seems probable that the highest sluu-e line has not yet lieen recognized in tiiose parts. I am, therefore, much m(/re confident of the truth of a statement made in a l)revious paper,* that the upper beach of theNipissing region is one with tile Irocpiois beach of the Ontario basin. The coun- try through which the connecting link prol)al)ly passes is ex- tremely rough and the dittieulties of exploration will be great, but prol)ai)iy not greater than those of some other regions where good results have rewarded perseveri ng explorers. *'-Thf Highest (H<1 Sliorc Liui'on Mackinac Island,'" Am. .lour. Sci., Ill, vol. .xi.iii. W. 2W-2\H, March, 18!t;2. 2S6 The American Geoloffist. November, 1894 .t At several of the jjlaces mentioned the shore lines are in lon^ valleys between tlie hills, and must have heen many miles from any larj^e open water. This is the case especially at Huntsville, Ikirk's Falls, Sunilridge, and South River. On this account it might be thouglit tiiat these evidences of sub- mergence were not produced by the wider waters which filled tl'2 basin of the upper lakes, l)Ut were due to lakes of the gla- cial recession, or to some other local cause. But I am (juite certain tliat sucli is not the case. Tiu'se valleys are wide and have open connection with the broader lake l)asin outside, and the plane of the sliore lines in them appears to be the same as that of the greater outer beaches. These valleys open to the southwest and west, away jrom the probable direction ot ice retreat. The one whicii passes Sundridge and South River opens both to the southwest and north. The magnitude of the phenomena also comports well with the strengtli and charac- ter of the outer lines. At the time of the great submergence this coast was somewhat like the present coast of Georgian bay, except that both channels and islands were on a much larger scale. Tlie highest part of tiie higiilands lies ^0 or 40 miles to the east of Burk's Falls, and is comprised in tiie Al- gon(iuin Park lately projected by the Canadian government.* Fro'i' all that I have been alilc to gather concerning the char- acter of that region it seems probable that .icarly the whole tract was intersected by channels wliicli cut it up into i^.lands. The highest lakes reported in tliat region have an altitude of about 1,405 feet above the sea. In the Sinicoe region and to the west Dr. Spencer found a marked rise of the Algonquin beach toward tlie east. Our obscivations in the same region were less extended and less precise than his, but so far as they go they show the same re- sult. For instance, the locality near Lorneville is about 30 miles east from Barrie and only two or tiiree miles north. But the beach at tile former place is about li.") feet higher than at the latter, showing an eastward rise of nearly one foot per mile. Orillia is about li{ miles east and the same distance north from Barrie and the beach is about 50 feet higlier, show- ing a rise of more than three and a half feet ])er mile to the *Ki'l)urt of tile ("ommissioii tm Foi-i'st Prcservulioti uiid Nttlioiiiil Parks, flc, lSi)3. Poafylocial Siihrnerijeuce eont of Genrfiidn hitij. — Taijluv. 2H7 northeast. The V)eiicli near Midland is about 22 miles west and ten nortii from Orillia. IJiit its level is ten feet lower. This probably does not mean a northward descent from Oril- lia, but rather a stronjj; eastward rise from Midland. From the loeality near Lorneville to that near Midland is about 40 miles west and 20 miles north ; but the beaeh at Lorneville is five feet the hij^her. The beueli at Karrie, however, is 40 feet below that at Midland, showinjj; that the apparent absence of the northward rise is due to the obseurinfj; eJfeet of the east- ward rise. The same is probably the case between Midland and Orillia. The value of a comparison where the dilierenees are small, however, is considerably impaired if it depends on measuremer'ts maile by aneroid barometer, as is the case with our work. From Orillia to North Bay the direction is nearly due north, and the intermediate places deviate l)ut little from that line. The measurements of altitude are probably fairly accurate at all the places except Brace'- ' Ige, where the weather condi- tions were not good, and themarjijin of error may be somewhat larger. Taking the figures as we have them, the northward rise from Orillia to Bracei)ridge is a trifle over 4 feet per mile; from Bracebridge to Iluntsville, less than Hfeet; from Ijunts- ville to Sundridge, about (i feet and 2 inches: from Sundridge to South Hiver, about JJ feet; and from South Kiver to North Bay, a northward descent of )il)out 2| feet per mile. Perhaps the most interesting result of these excursions was the finding of the great silt beds. When we take into ac- count all their relations to the adjacent glacial and postgla- cial deposits, the wideness of their distribution, and their remarkable uniformity of composition in all places, it seems impossible to miss their meaning. These deposits were found not only in the highlands east of Georgian baj' as here de- scribed, but also at several other distant places. They were ft)und at Superior opposite Duluth, and at Sault Ste. Marie; at many points along the Spaiush and White Fish rivers north of lake Huron ; all along the north side of lake Nipissing, and up the valle}' of the Veuve ; at Pawassan, Trout ('reek. South River, liurk's Falls, Huntsville and Bracebridge, on the line of the Northern and Pacific Junction railway; in the valley of the Oswegatchie river near Fklwards and South Ed- 2K8 The Amerii'dii Geolfxjist. Novpmher, 18«4 ^% wards. N. Y. ; ami a^nin in the valley of the MlHsiHciuoi river in northern Vermont. In all these places this deposit presents not only the same jjjeneral appearance and relation to other contiguous deposits, hut also a remarkahh^ uniftrmity of finer details. Take, for example, the silt heds at Hracehridfjfe. The whole set of phenomena at this place is extremely in- structive. The laminations of clay and silt arc associated in pairs which are almost without i xception aitout half an inch in thickness. ():i weathered surfaces the principal part of each layer is a fjjreenish gray day, and this is separated from the i\ext layer of clay in each case by a layer of white silt, an eighth to a sixteenth of an inch in thictkness. There are some variations in the composition of the deposit at each 'ocality, hut they are ;'onfined ehietly to varying jjroportions of the two materials. In a tew places I found the clay almost ah- seiu md the silt layer thicker than usual. In other i)laces the variation was reverse of this. It seems plain enough that the silt and tiie clay must represent two slightly diU'erent conditions of sedimentation ; aiul the orderly way in which the layers alternate shows that a layer of silt and a layer of clay taken together .'onstitute one complete round of change. This points to recurrence and almost certainly to peiiodicity. Tides, storms, and the annunl round of the seasons, are the only recurrent variations liable to all'ect sedimiMitation. Of these the tides and the seasoiis are periodic, but storms are irregular. Neither tides nor storms aH'ord a satisfactory ex- planation. For the one is much too short in its period, and the other too irregular. It seems imixis.qble that the pairs of layers can represent anything but annual periods of deposi- tion, and if this be the case several im})ortant conclusions follow. Considering the great thickness of the whole deposit, the length of time which must be allowed for its formation can hardly i»e less than several thousand years. Indeed, if we suppose the laminations to be uniform, and the maximum dtpth of the whole original deposit to have been 100 feet, the time of deposition would be about 2,500 years. And this, it shoiild be noted, would be not the whole time of the submer- gence, but only the time during which the conditions of .still- water sedimentation existed at that level, not counting the two periods unfavorable to this kind of sedimentation, one as f w J^\ WUH n„ u it: ' ' ^^"'""""y that the .ul,nHM-f.c.„n. !'.:or"::;,;;;,T;,;L'.'"",i,r;;; "-"r "': ■'-'■"■■• "' -" tl.» »h„r<. Ii„c.« , „v,. ' " '? "'"'•'"' '•'■»«"»!""■ Hut the oc-ntcT or ,h 1 , " ■"°"'' "" ''"■ "'"(''""a toward »«. «n,l ,l,„t tl ', "■"■'■«""- »■"» "" i"v„«i.,„ „f the " »tt„it „ve r ; 'It t;'" T^ '■"'?""■" """ ■' """"«'> r."n, ti. N*„„ b™:.i;'::;;i„ ;cx; ;;";■ ^^^ -i"" l-.n. -n .h.. Ot,„„.„ Hv„ „b„vo Matt "V .",;:'::" ™«..n ... expect that „xplo,,„i„„ will ,H,l,„„,ol prove thlt the upper .,!.. „„„ ^.,,„,,| be„elu.» ..r the hh-hla,