Mesozoic and Cenozoic Geology and Paleontology. 195 
puted, as a large part of it lies below the lake level, forming the bed of 
more than one half of Lake Erie. On the south shore it extends but 
a short distance into the interior, forming a narrow belt of low country 
along the lake, and thinning out as the rocks upon which it rests rise 
to the southward. 
The “ coarse sand and gravel” of this division, rests conformably on 
the “blue marly sand,” and spreads horizontally over a tract of low, 
and in general wet land, embracing the western half of Lake Erie, and 
extending westward into the States of Ohio and Michigan. 
On the north, it forms the soil and surface over a large portion of the 
peninsula, between Lakes Erie and Huron; which seldom rise more 
than 200 feet above the waters of these lakes. On it, and composed of 
its coarse water-washed sand and gravel, are seen the “lake ridges,’ 
objects of curiosity, and of much utility in a new country, being nat- 
ural turnpikes that run parallel with the shore. At Cleveland the 
section is as follows: Ist. Gray, water-washed, coarse sand, resting on 
the blue marl, 10 feet. 2d. Coarse gravel of the adjacent rocks and 
sand, 20 to 40 feet. The lake ridges are not precisely horizontal, and 
are found at various elevations, 30, 90, 120 and 140 feet above the water. 
There are branches and cross ridges uniting different parallels, that 
rise and fall several feet in a mile. 
6th. Bowlders or “ erratic rocks” which he regarded as a “ stratum,”’ 
and the newest of all beds except the alluvium. 
The Drift deposits* are verv extensive on the southern shore of 
Lake Superior, and more especially on its southeastern coast. There 
they not only constitute the only visible formations for nearly 100 
miles, but they also attain an astonishing thickness, so as to form, by 
themselves, ridges and cliffs which exceed in height even those of the 
Pictured Rocks, being in some places, as at the Grand Sable, not less 
than 360 feet high. The Drift is less conspicuous along the western 
portion of the lake shore, although it is not wanting even among the 
romantic and precipitous cliffs of the Pictured Rocks and the Red 
Castles. 
The Drift of lake Superior may be divided in ascending order, into— 
Ist. Coarse drift. This is the least conspicuous of all. It is found 
only in a few places along the southern shore, generally capping the 
high towering cliffs of sandstone. It is generally a mixture of loam 
and fragments of rock of different sizes—sometimes worn, but more 
generally angular. As a leading feature, it is almost exclusively com- 
* Foster and Whitney’s Sur. Lake Sup. Region, 1850. 
