760 GEOLOGY OF OHIO. 
a hundred feet before reaching the bottom of the till. Through Licking 
county, both north and south of Newark, the depth of the glacial. 
envelope is great, up toa short distance of its eastern edge. At the 
reservoir, in Perry county, the distinct features of a moraine come out. 
The hill upon which Thornville is built is a mass of glaciated material 
in which wells descend from thirty to fifty feet without striking rock. 
This is upon the highest land of the vicinity. 
The reservoir itself seems to be a great kettle-hole or moraine 
basin. All through Fairfield county, the glacial accumulation is of 
great depth down to a very short distance of its margin. But perhaps 
the most remarkable of all the portions of this line in Ohio is that run- 
ning from Adelphi, in the northeast corner of Ross county, to the 
Scioto River. The accumulation at Adelphi, as shown where Salt 
Creek cuts through, is more than two hundred feet, and continues at 
this height for many miles westward. Riding along upon its uneven 
summit, one finds the surface strewn with granite boulders, and sees 
stretching off to the northwest the magnificent and fertile plains of 
Pickaway county, while close to the south of him, yet separated by a 
distinct interval, are the cliffs of Waverly sandstone, rising two hun- 
dred or three hundred feet higher, which here and onward to the south 
pretty closely approach the boundary of the glaciated region. Through 
the southeastern corner of Highland county and the northwestern of 
Adams, the terminal accumulation is less marked than in Ross county ; 
still, the boundary of the glaciated region is easily determined. It ap- 
proaches the river in the vicinity of Ripley, in Brown county, and 
crosses it from Clermont county, so as to enter Kentucky a half mile 
north of the line between Campbell and Pendleton counties. Cincin- 
nati, as I have said, was covered with ice during a portion of the glacial 
period. There is an undoubted deposit of till at the railroad station at 
Walnut Hills, nearly four hundred feet above the river. At North 
Bend the tunnel of the Indianapolis, Cincinnati and La Fayette Rail- 
road, leading from the Ohio to the Miami, is through an accumulation 
of till which rises 200 feet above the river. | 
I have given special attention to glacial terraces (see American 
Journal of Science, July, 1883), particularly at those points where 
streams pass from the glaciated into the unglaciated region. Here very 
generally there are extensive accumulations of coarse gravel and pebbles, 
such as naturally would be deposited in the last stages of the glacial 
