Mesozoic and Camozoic Geology and Palceontology. 299 



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 sonth 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 marl}^ 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: 1st. 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 very extensive on the southern shore of 

 Lake Superior, and more especiall}^ 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 cliff's 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 — 



1st. Coarse drift. This is the least conspicuous of all. It is found 

 onl}' in a few places along the southern shore, genei'all}' 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. 



