Tnterglacial Fossils. — Coleman. 93 
bringing down rock Hour from the not far distant ice front. 
as the upper waters of the Athabasca now do, and depositing 
it on the floor of a lake too muddy and cold for life. 
A further advance of the glacier buried the stratified clay 
beneath 30 or 40 feet of sandy clay and sand containing num- 
berless subangular. striated stones and some boulders of Lau- 
rentian and Silurian rock several tons in weight. These ma- 
terials show little or no stratification and are not waterworn 
so far as I have observed. The striae on limestone pebbles are 
sharp, and there are Hat pebbles of soft LTtica shale here 20 
miles from home, which woidd have been destroyed if trans- 
ported by wave action orb}* running water. The cla3*s under 
this second glacial deposit appear to have been very little dis- 
fcurbed by the passage over them of the glacier. 
When the ice of the second glacial epoch retreated, the 
lakes, whether dammed by an eastern tongue of ice or lowered 
to the level of the sea, formed a beach now 140 feet or more 
above the lake, Spencer's Iroquois beach.* Wave action re- 
moved the loose materials as far as the Davenport ridge, which 
forms so prominent a feature of the northern part id' the city, 
the heavier stones being left where they rested as a boulder 
pavement. At the Iroquois stage the lake is considered to 
have drained into the Hudson. Several of the Ullios 
exterminated by the second advance of the ice did not re- 
turn when the ice retreated again. Was the continuously icy 
water unfavorable to the species which failed to return? Mr. 
Simpson supposes that some change in the drainage system 
prevented fchem from regaining the lost ground. \ The change 
from the Iroquois level to the present one must have been 
rapid, leaving no time for the formation of intermediate 
beaches. Since the change of level the Don and its tributa- 
ries have had time to remove the drift deposit- down to 
base line for more than a mile north of Toronto bay. 
Noii: ox Interglactal Plants prom the Don Valley. 
By Prof. D. P. Pen hallow, 'McGiU University, Montreal. 
From time to time there have been brought to light a num- 
ber of interesting plants from the interglacial formation of 
*Deformation of Iroquois Beach and Birth of Lake Ontario, Am. 
Jour. Sci., Vol. xl, Dec, 1890, p. 446. 
"fProc. Nat. Museum, Vol. xvi, p. 595. 
