14 TRANSACTIONS OF THE CANADIAN INSTITUTE. (VoL. VIII. 
sands again appear between the two sheets and the cliff section is about 
fifty feet in height. At three miles the upper till overlies the sands and 
the lower till lies below lake level. From this point for the next two 
miles the shore-line is marked by a barrier beach, the land behind is 
low and marshy. Then two low domes of the lower till form a low cliff 
for about one-quarter of a mile. A second barrier beach more than a 
mile in length intervenes between these low cliffs and the next series of 
deposits into which the waves have cut. From this place, about two 
and one-half miles west of Port Granby, to Newcastle pier there is a 
continuous section over eight miles in length, except for slight interrup- 
tions where two small creeks enter the lake. This section may be 
termed the Clarke section, because the greater part of it lies within the 
township of Clarke. 
The structure of this section is much more complex than that of any 
of the preceeding sections and it has accordingly been studied in more 
detail. Theshore line of Lake Ontario, represented on the accompanying 
map, was surveyed by means of a Rochon micrometer and a surveyor’s 
compass, the relative positions of the various sections being determined 
at the sametime. The writer is much indebted to the Rev. E. M. Burwash, 
of Toronto, for assistance in the prosecution of the survey. The 
topography north of the shore line is taken from a county map, and al- 
though it is not as accurate as could be desired, it will serve to show 
the relative positions of the various sections. In studying these deposits 
about thirty-five vertical sections were measured, generally by means of 
a hand level and jacob’s staff, and of these, sixteen, at intervals of half 
a mile, are represented in the upper part of the accompanying plate. 
The cross section shown in the middle of the plate represents a con- 
tinuous cross section of the deposits with a vertical exaggeration of 
ten. 
Proceeding from east to west, at two miles east of Port Granby, a 
lower till is exposed in a low cliff. As we go west the cliff gradually 
increases in height. At the end of the first half mile this lowest till 
sheet is found to be overlaid by another sheet of an arenaceous till, 
which will be termed the third till sheet.* The eastern edge of this till 
sheet is well marked by a sudden increase in the height of the cliff; it 
continues inland as a low terrace. Half a mile further west these two 
till sheets are separated by about thirty-two feet of cross bedded strati- 
fied sands (Section 2). A short distance west of this section the sand 
beds immediately beneath the arenaceous till overlie a series of fine 
* The characteristics of the different sheets of till will be described below. 
