Dr. J. W. Dawson—Canadian Pleistocene. 111 
the case of Jolly’s balance, the degree of accuracy obtainable being 
about the same in both cases. 
(8) Walker’s Balance is less cumbrous, lighter, and less likely to 
suffer injury in transport than any contrivance for the same purpose 
with which I am acquainted. 
I may add in conclusion, that I have recommended Walker’s 
Balance to many travelling geologists, and I find that by those who 
have employed it, it is universally well spoken of. 
TV.—CanabDian PLEISTOCENE. 
By J. W. Dawson, LL.D., F.R.S., etc., ete. 
EFERENCE is sometimes made, in the course of the active 
discussion of the Glacial age in the GroLocican MaGazinu, 
to the Pleistocene of Canada, a country which, perhaps, as much as 
any other, in its great extent from the Atlantic to the Pacific, and 
from latitude 45° to the Arctic Sea, affords opportunities for the 
study of the deposits of this period. It has occurred to me, in 
connexion with this, that it might be useful to your readers to 
present to them a short summary of Canadian facts, as I think I 
have established them in publications on this subject, which are, 
perhaps, better known in this country than in England. 
In the St. Lawrence Valley, which may be regarded as a typical 
region, VES deposits may be tabulated as follows, in ascending 
order : 
(a) Peaty beds under Boulder-clay. These represent land surfaces and sea 
(6) Lower stratified sands and cca | and coast areas immediately anterior to 
(Syrtensian deposits of Matthew). the Boulder-clay. 
(c) Boulder-clay or Till; hard clay, or) The Lower St. Lawrence region holds 
unstratified sand, with boulders, local | a few marine shells of Arctic species. 
and travelled, and stones often striated + Farther inland is non-fossiliferous, but 
and polished. | has usually the chemical characters of 
) a marine deposit. 
(d) Lower "Leda clay; fine clay, often Holds Leda (Portlandia) arctica, and 
laminated, and with a few large travelled sometimes Tellina groenlandica ; and 
boulders, probably equivalent to Erie (seems to have been deposited in very 
clay ° of inland districts. cold and ice-laden water. 
(e) Upper Leda clay, and probably San-\ Holds in Kastern Canada a marine 
geen clay? of inland districts; clay and | fauna identical with that of the northern 
sandy clay, in the Lower St. ‘Lawrence, tpart of the Gulf of St. Lawrence at 
with numerous marine shells. | present; and locally affords remains of 
ja boreal flora. 
(f) Saxicava sand and gravel, often with Shallow-water fauna of boreal cha- 
numerous travelled boulders = ih) racter, more especially Saxicava rugosa 
Boulder deposit), probably me same | and its varieties. Bones of Whales, etc. 
with Algoma sand, etc., of the West. 
(g) Post- Glacial deposits, river alluvia and 
gravels, Peaty deposits, Lake bottoms, ti 
etc. 
The Lower Boulder-clay (c) is often a true and very hard Till, 
resting on intensely glaciated rock-surfaces, and filled with stones 
and boulders. Where very thick, it can be seen to have a rude 
stratification. Hven when destitute of marine fossils, it shows its 
1 Supplement to Acadian Geology, 1878. Notes on Post-Pliocene of Canada, 
Canadian Naturalist, vol. vi. 1871. 2 Geology of Canada, 1863. 
Remains of Mastodon and Elephas, 
modern fresh-water shells. 
