2n4 Canadian Record of Science. 
which was affected by after changes. The relative positions 
of these strata around the lake further suggest this. 
Another feature, however, has played an important part 
in the formation of not only Lake Ontario but also of Lakes 
Huron and Michigan, and even had its strong influence on 
Lake Erie as well. The Niagara escarpment, which nearly 
fronts the southern side of Lake Ontario, passes around its 
immediate westerly end, and then, facing to the north-east, 
continues in a somewhat irregular north-westerly direction 
until it eventually forms the prominent features of the 
Bruce Peninsula between the Georgian Bay and Lake 
Huron. At Cabot’s Head, at the end ofthis peninsula, there 
is a break, but this is only apparent as there is a subaqueous 
ridge here, commencing near Cape Hurd, with deep water 
on the Georgian Bay side. This ridge, through the neigh- 
bouring islands, connects the peninsula with the Manitou- 
lin Islands. The same limestones re-appear, crossing these 
islands, in bold escarpments facing to the northward, and 
extend uninterruptedly to the State of Michigan, the height 
diminishing to the westward. Along the northern shores 
of Lake Michigan they continue until Green Bay is reached, 
where, facing to the westward, they once more in places 
rise into an escarpment. Here they form two horns of the 
bay, with islands and another subaqueous ridge connecting 
them. Thence these limestones are found in the country 
skirting the western shores of Lake Michigan and they 
probably form the floor of its southern end beneath the 
superficial deposits. 
The dip of the strata is, from the escarpment north of 
Hamilton and on the Manitoulin Islands, to and under the 
waters of Lake Huron. From Dundalk station on the 
Toronto, Grey and Bruce Railway, on the summit of the 
escarpment, there is a fall of 1,119 feet to the level of Lake 
Huron at Kincardine, seventy miles distant. South of the 
valley of the River Thames, which lies on the Cincinnati 
anticlinal, and at Niagara Falls, the slope is towards Lake 
Erie. To the north of the cliffs, on the Grand Manitoulin 
Island, are parallel escarpments of Hudson River age, form- 
