88 The American Geologist. Feb. 1891 
movements," yel such crust-movements bad not been tested in the 
American take-region. Again, from the time of early geological 
investigations in America, statements are found that the basins 
were the result of erosion ; hut the methods of erosion were not 
explained, and this was the more necessary as most of the basins. 
have rock-hound outlets. Later in some geological literature, tin- 
method of excavation was hypothetical lv attributed to glaciers. 
Such was the unsatisfactory condition of our knowledge of the 
problem when the writer first commenced the study, in attempting 
to solve the origin of the Dundas valley, at the western end of 
lake Ontario, more than a dozen years ago. This investigation 
has developed results bearing not only upon the origin of the lake- 
basins, but also upon the physical history of the lakes, and 
broader questions of the building and sculpturing of the continent. 
The methods of investigation have been the studying — (l)of 
the hydrography of the modern lake-basins and submerged chan 
nels upon the coast of America '• ( 2 ) of the deep wells bored into. 
Or through, tin; drift Deposits, by which buried channels, and 
their relation to or contrast with the modern valleys, have been 
discovered: (3) of the elevation of the continent; (4) of the 
direction of the glaciation in the Lake-region ; and ( ."> ) of the now 
high-level beaches, in which are recorded continental uplifts, to- 
gether with the deformation of the old surfaces, owing to unequal 
terrestrial movements or warpings of the earth's crust*. The 
lakes which have been the basis of the more careful investigation 
are Ontario, Erie, Huron, and Michigan, with the respective alti- 
tudes of 247. .")7:i. and, of the last two. 582 feet above the sea' 
( see the map p. 87.) 
2. Featitres of the Ontario l><tsln. 
Lake Ontario, as was shown in an earlier publication!, is a basin 
bounded on its southern side by escarpments, often precipitous. 
of which some of the steps are now submerged. At the foot of 
the submerged escarpments a valley like that of an ancient river 
may be recognized from the western part of the lake to near the 
eastern end, but there it disappears, for reasons to be noted later. 
*In the field-work I here acknowledge the assistance of professors 
D. F. H. Wilkins. YY. W. Clendenin. and W. J. Spillman. 
f" Discovery of the preglacial Outlet of the Basin of Lake Erie into 
that of bake Ontario." by 1. \Y. Spencer; Proc. Am. Phil. Soc, Philad. 
1881. 
