oT 
40 TRANSACTIONS OF THE CANADIAN INSTITUTE. [VoL. VI 
of the unios said to have been found in beach ridges of New York 
State, no shellfish have been discovered except in the neighbourhood 
of Toronto. It is believed, however, that the Toronto finds are fairly 
conclusive that the water was fresh; and the evidence is strengthened 
by the fact that fresh water shells are found in deposits of most of the 
other great bodies of water that followed the retreat of the ice. 
In the beaches of Lake Agassiz Warren Upham notes Uxzo ellipsis 
from Campbell, Minn.; and four species of shells occurring in consider- 
able abundance near Gladstone, Manitoba, about 875 feet above the 
sea, Unto luteolus, spherium striatinum, S. sulcatum-and Gyraulus 
parvus. \ have collected a unio, probably rectus, and two species of 
spherium from the stratified clay of Rainy River, Ontario ; deposits 
laid down in Lake Agassiz, according to Upham; but belonging to a 
separate lake, according to Tyrrell. Dr. Bell has found freshwater shells 
in old lake deposits north of Lake Superior ; and Professor Chapman, 
formerly of Toronto University, names eleven species from Angus, 
south of Georgian Bay, in beds probably formed by Lake Warren, but 
possibly by Lake Algonquin. Chapman’s list includes Unzo complanatus, 
Cyclas (Spherium) similts, C. dubia, Amnicola porata, Valvata tricart- 
nata, V. pisctnalis, Planorbis trivolvts, P. campanulatus, P. bicarinatus, 
Limnea palustris and Physa ancillaria.* In my own collection made 
in the same region Dr. Dall has named eighteen species, including 
Unio luteolus, Spherium sulcatum, S. rhomboitdeum, Pistdium novabor- 
acense, Valvata sincera, Amnicola limosa, Succinea avara, Gontobasts 
livescens, Planorbis deflectus, P. parvus, Limnea decidiosa, L. elodes, and 
Polygyra monodon, in addition to those found by Chapman. Similar 
shells are found at other points near Georgian Bay, and in the latter 
case as well as on Rainy River the shells are very widely spread and 
must have inhabited the waters in which the silts and sands containing 
them were laid down. 
On the other hand there is no record of a marine shell being found in 
any of the old beaches of the Great Lakes region, though these are 
common on the St. Lawrence below Brockville, on the Ottawa to the 
northeast, and in raised beaches along the rivers flowing into Hudson 
Bay on the north. If the sea had formed our raised beaches one would. 
expect to find marine shells in these just as we do along the rivers to 
the east and north. 
There are a few organisms living in our great lakes identical with or 
closely related to marine species, and this has suggested to some writers 
that the Canadian lakes were once arms of the sea, Relzktenseen of the 
* Geol. Can. p. 912. 
