288 The American Geolnnhi. May, 1895 
referred to existing species, but tlie nearest alliesofnota few of them are 
to be sovi<j:ht in tlie Lal<e Superior and Hudson Hay re<!:ion. while tlie 
larger part are inhabitants of Canada and th(i nortlieni I'liiled States, 
or the general district in wliich the deposit occurs. In no single in- 
stance were any special attinities found with any characteristically 
southern forms, though several an' most nearly allied to species found 
there as well as in the north. A few seem to be most nearly related to 
Pacific forms, such as the Elaphrus and one each of tlie species of Pla- 
tynus and Pteroslichus. On the whole, the fauna has a boreal aspect, 
though by no means so decidedly boi'eal as one would anticipate under 
the circumstances. 
It seems quite certain that the fossiliferous beds of these 
two localities were approximately contemporaneous, and that 
the glacial reiidvances pushing westward and forming the two 
thick boulder-clay deposits in Scarboro' brought only thin 
and discontinuous boulder-clay beds in Toronto. Much of the 
stratified clays, sand, and gravel, may have come from engla- 
cial drift of the neighboring ice-sheet on the northeast, being 
brought b}^ streams from its melting; while the driftwood 
and leaves of trees, and mosses of peat bogs, growing within 
a few miles westward, were contributed to the same deltas by 
streams flowing from a wooded land area bordering the ice, 
such as Russell found adjoining the Malaspina ice-sheet in 
Alaska and even extending its forest growth several miles 
upon the drift-covered margin of the departing ice. The gla- 
cial retreat from the northern United States and southern 
Canada, after the culmination of the depression of the land, 
with which the lowan stage of glaciation terminated, is known 
to have been geologically very rapid ; and the warm climate 
which caused the ice-sheet to be fast melted awa}^ appears to 
have permitted a temperate fauna and flora, similar to those 
now found in the same latitude, to follow close upon the re- 
tiring ice-border. Another excavation in the Toronto drift 
has supplied a maple leaf named Acer pleisfooenicnin by Prof. 
Penhallow. and wood which he identifies as Asimina triloba 
and Ulmuf! recemosa, species which now have their northern 
limits in the southern part of the Province of Ontario. When 
the land had its Preglacial and Glacial high elevation, a se- 
vere climate prevailed along the border of the ice-sheet at its 
times of growth; but with the depression of the country be- 
neath the ice burden, a great change to nearly the present cli- 
matic conditions along the glacial boundary caused it to 
