Notes on the Drift and Alluvium of Ohio and the West. 209 
banks, on both the American and Canadian shores.—{See section. ) 
These avalanches of earth are from one to four rods in width, 
breaking off in irregular patches, and sometimes sinking, in a night 
or ina few hours, twenty or thirty feet, leaving huge fissures 
through which the water of the springs passes, and rapidly wash- 
ing the earth into the lake. 
ca 
eZ 9 
Section from Cleveland. Ohio, to the Highlands, southwest. —a, Lake Erie; 8, 
Cleveland ; c, slides; d, ridge ; i 
At the water’s edge, the slide frequently raises a bank of about 
the width of the break, several feet above the surface, driving 
back for a short time the line of the shore. But the waves act- 
ing incessantly dissolve the new barrier, and soon commence their 
attacks upon the bedy of the fallen mass, which disappears, and 
is before long followed by a fresh avalanche from a ove. 
At the city of Cleveland, where the bluff shore rises seventy 
feet above the lake, the encroachment since the survey of the 
town in 1796, has been at the foot of Ontario street 265 feet. 
The Canadian shore, from Detroit River to Long Point, is losing 
faster than the American. Between Port Stanley and Port Bur- 
well on the British side, the superior face of the blue marl is 
about sixty feet, or fifteen feet higher than at Cleveland, and has 
in the upper part a lighter or more yellow color. In composition, 
the yellowish portion is more argillaceous than the bright blue, 
aud appears to correspond with the yellow clay stratum e 
Champlain, 
The greatest thickness of the blue marls cannot be computed, 
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.—(See section. ) 
The “coarse sand and gravel” of No. V, rests conformably on 
No. Lof that division, and spreads horizontally over a tract of 
low, and in general wet land, embracing the western half of Lake 
ie, and extending westward into the states of Ohio and Michi- 
gan. On the north, it forms the soil and surface over a large por- 
