GLACIAL BOUNDARY IN OHIO. 757 
the central part of the State, many feet below the surface, granite from 
Canada, Corniferous limestone, and fragments of sandstone, all striated, 
and intimately mixed together in the paste formed by the grinding up 
of the Ohio shales. Large granite boulders are thickly strewn all over 
the surface of this glaciated area. Some of the largest found in the 
State occur upon the very border of the glaciated region. A granitic 
boulder, found in Columbiana county, near Lisbon, is 13x11x8 feet out 
of ground. Another, near Lancaster, in Fairfield county, is 18x12x6 
feet out of ground. Granite boulders from three to five feet in diameter 
are too numerous to mention. 
The average depth of the glacial deposit over the area in Ohio, 
north of this boundary line, is estimated by Mr. EK. W. Claypole (see 
Proceedings of A. A. A.S., vol. XXX, p. 151), to be fifty-six feet. No 
one at all familiar with the region will be disposed to think this estimate 
exaggerated. 
The inexperienced observer will, however, frequently be confused 
by the evidence of water action in connection with the till. He should 
bear in mind that during certain seasons of the year large floods of 
water accompanied the glacier at all stages of its progress. Sometimes 
the water escaped by sub-glacial streams, at others by superficial 
streams; in all cases flowing towards the front, and making stratified 
deposits in places where there are now no streams, and which, while the 
glacier was advancing, might be covered by deposits of till. Again, as 
the glacier was retreating, there were vast floods from the melting ice, 
leaving terraces of coarse gravel in all the existing streams, as well as 
superficial deposits of sand and gravel in many places where no streams 
now exist. 
The southern margin of the glaciated area of Ohio is not every- 
where marked by such a relative excess of accumulation of glaciated 
material as is found through Cape Cod, on the Elizabeth Islands and 
Long Island, and at various places in New Jersey and Pennsylvania. 
The limit, however, everywhere is very sharply defined, and at various 
places, soon to be mentioned, in Stark, Holmes, Fairfield, and Ross 
counties, the marginal deposition is on a scale equal to anything which 
can be found in the south of New England. 
The glacial limit enters Ohio from the east, in Columbiana county, 
at Achor, twelve miles north of the Ohio river, and. continues nearly 
west to the middle of Stark county, where it turns more to the south, 
