CANADIAN TLEISTOCENK FLoHA AND FA IN A. » 



since provided cvidonco favoiirini,' llic intorf^lacial age of the sands. At 

 tlie sewer stratitied sand, evidently a continuation of the deposits just 

 UK'ntioned, contains chiyey sheets witli thin bands of peaty material con- 

 taining leniains of beetles, mosses, seeds, plates of iniea, it'c, precisely like 

 the peat from the cold climate series of Scarborough and tlio l)on 

 valley. Since these peaty layers are probably eijuivalent in age to the 

 ])eaty clays east of the city, %ve may suppose that the sandy dejiosits of 

 the westtrn part of Toronto are also interglacial, in the upper part evi- 

 dently belonging to the cold climate series, but perhaps representing the 

 NViiini climate deposits at lower levels. It is clear that the conditions in 

 AVestern Toronto must have been ditl'erent from those to the east, 

 since heie a gieat thickness of stratified sand replaces stratified clay. 

 This may be explained by supposing that an interglacial Ilumber river 

 brought from the west sand and gravel into the great lake then occu- 

 pying the Ontario Valley to mingle with the clayey delta materials of the 

 interglacial Laurentian river flowing from (leorgian Bay to Scarl>orough. 

 Just beneath a thin sheet of till in the Dupont Street sewer the uj'per 

 end of the ulna of a mammoth or mastod( n was found, the bone having 

 been polished and sciatched by giacial action, suggesting that it lay on 

 the surface when the ice advanced for the last time. Some pieces of wood 

 occurred near by, but lower down in the section. 



AVe may now sum up the results obtained by the Comniitt«'e and 

 former investigators of the Toronto foimation, so as to show the series of 

 events recorded, the thickness of the deposits, and the fossils obtained from 

 them. 



In most places the Toronto formation is fcund to overlie a bed of cha- 

 racteristic boulder clay containing rocks brought from long distances to 

 the north or north east, and covering the eroded surface of the Cambro- 

 silurian rocks of the region. This boulder clay probably belongs to the 

 lowan till sheet of the I'nited States. After the retreat of the ice there 

 was an interval of erosion shown near Shaw Street, and in the interglacial 

 river valley at the bend of the Don ; folhjwed by the deposit of clay, sand, 

 and gravel containing trees and unios of a warmer climate than the 

 jiresent, the greatest thickness amounting to thirty -three feet in the I)on 

 valley, and to thirty-five feet below Lake Ontarn> at Scarborough. 



These beds have nowhere been found at a higher level than fifty feet 

 above Lake Ontario, and the upi)er sands and gravels were probably laid 

 down in sh.allow water, since tliey are browned and sometimes cementeil 

 with oxide of iron. 



Conformably upon the warm climate beds are a s*»ries of be«ls 

 containing trees and other fossils, especially Ix-etles, suggesting a icoler 

 elimat(« than the ])resent ; not Arctic, however, but cold temperate. 

 I'hese are best shown at Soirborough Heights, where stratified peaty 

 clays starting a few fcrt below the level of Lake Ontario have a thiikness 

 of ninety-five feet, followed by fifty-five feet of stratitied sand. It is pro- 

 bable that part at least of the seventy feet of sand found in the western 

 part of Toronto is of the same age. The interglacial lake at this stage 

 must have stood at least L'»U fe«'t higher than I^-ike C)nfario. 



A long jH'riiwl of erosion fallowed the draining of this lake, during 

 win. li river valleys a mile or more in width were cut through the delta 

 deposits at Scarborough to the depth of more than 1 50 feet comparable to 

 those cut by the Don and Humljer smce the (Jlacial period. 



Finally a fresh advance of the ice, probably belonging to the Wisconsin 



