638 THE JOURNAL OF GEOLOGY. 
till at the Don is the equivalent of the ninety or more feet of 
peaty clay at Price’s brickyard and Scarboro’; and one might 
expect to find the unio bed, or its equivalent as to climate, 
beneath the level of the lake at Scarboro’. It should, however, 
be observed that up to the present no species has been shown to 
be common to the peaty beds of the Don and those of Scarboro’, 
except one ubiquitous shellfish. It may be that future excava- 
tions will settle which hypothesis is correct; if, indeed, some 
entirely different interpretation may not be put upon the facts 
described. 
Two very interesting articles have appeared recently, one by 
Professor Chamberlin in the JOURNAL oF GEOoLoGy, the other by 
Mr. Warren Upham in the American Geologist, referring to the 
succession of glacial deposits in America, and mentioning the 
Toronto inter-glacial beds in that connection. Professor Cham- 
berlin gives the ‘“Toronto Formation” tentatively an independent 
position as the possible equivalent of Geikie’s Neudeckian,’ and 
places it in the interval between the Iowan and Wisconsin sheets 
of till. Mr. Upham places the Toronto inter-glacial beds in a 
somewhat similar position, but looks upon them as only in a 
limited sense inter-glacial, ‘‘since they lie between deposits of 
glacial drift; but they seem better referred to moderate oscilla- 
tions of the ice boundary during its general retreat after the 
Iowan stage, that is, to a time during the Wisconsin or moraine- 
forming stage rather than to distinct glacial epochs.”* He sup- 
ports this view by a statement as to thinning out of the beds of 
till between Scarboro’ and Toronto, suggesting the nearness of 
the ice border; and finds the deposits “quite inexplicable on the 
hypothesis that these till formations record great readvances of 
the ice, as either to the Iowan stage or to the Wisconsin 
moraines.’’3 
In regard to the thickness of the sheets of till it may be 
mentioned that they vary greatly in this respect within short 
‘JOURNAL OF GEOLOGY, Vol. III., No. 3, pp. 273-275. 
? Am. Geol., Vol. XV., No. 5, p. 289, etc. 
3Tbid., p. 290. 
