TORONTO GLACIAL AND INTER-GLACIAL DEPOSITS. 641 
Arctic climate, implying perhaps only a long recession of the 
ice, not its complete removal. The upper part, consisting of 
cross-bedded sand and clayey sand, seems quite widespread, for 
similar beds lying between the rolling surface of till and a lower 
sheet of till have been found on a branch of the Don seven miles 
north of the city, at Pickering twenty miles northeast, and on 
the lake shore near Newcastle forty miles to the east. It may 
be that fossils giving a hint as to the climate in this inter-glacial 
period will be found at some time. The tooth of a mammoth 
was found last summer on the Don eight miles north of the city 
at a point where the stream flows over the middle till and cuts 
away banks showing stratified sand and in some cases the uppe 
till also, but the fossil may be post-glacial rather than inter-glacia 
in age. The same holds of two mastodon teeth found several 
years ago, one on the Don, the other in a sand pit two or three 
miles east of the city. 
If Professor Chamberlin is correct in assigning the fossilifer- 
ous beds of Toronto and Scarboro’ to the interval between the 
Iowan and Wisconsin ice ages;* then the upper stratified beds 
imply a still later ice age, separated probably by a shorter and 
less genial inter-glacial time than the former one. It is however 
possible, as suggested by Professor Chamberlin, for the beetle- 
bearing beds of Scarboro’ in case they should prove to belong 
to a lower horizon than the Don beds, that the fossiliferous beds 
near Toronto are of Aftonian age, z. ¢., belong between the 
Kansan and Iowan sheets of till; and that the upper beds repre- 
sent the interval between the Iowan and Wisconsin ice sheets. 
The former supposition seems to me the more probable, since 
there is some likelihood that the mild morainic sheet forming 
the Davenport ridge and upper Scarboro’ Heights runs out in the 
neighborhood of Toronto, and hence cannot be continuous with 
the Wisconsin sheet to the southwest. Until the till sheet lying 
to the north and east of Toronto has its western boundaries 
traced this point cannot be settled. 
A long halt in the retreat of the last glacier, if not a recru- 
JOURNAL GEOLOGY, Vol. III., No. 3, p. 273, etc. 
