242 THE ICE AGE IN NORTH AMERICA, 



numerous granitic pebbles, showing that glacial deposits in 

 Lycoming county contain material from the far north which 

 has been carried bodily over the summit of the Alleghanies. 

 On proceeding west, the granitic outcrops from which the ma- 

 terial could come, gradually recede to the north, thus increas- 

 ing the distance between such bowlders and their nearest 

 known source. From Salamanca, N. Y., southwestward to 

 Cincinnati the whole country is literally covered, down to 

 the glacial limit, with granitic, gneissoid, and hornblendic 

 bowlders. Near Salamanca such bowlders abound at eleva- 

 tions not far from 1,900 feet above tide, and 700 feet above 

 the Alleghany River. In Beaver county they are numerous 

 on the hills down to within six or seven miles of the Ohio 

 River, and several hundred feet above it. 



The following are some of the more specific facts drawn 

 from my own notes : In Columbiana county, Ohio, a granitic 

 bowlder was found measuring thirteen by eleven feet, and 

 eight feet out of the ground. Others near by were noted, 

 measuring eight and five feet in diameter. In the same 

 vicinity the till contains finely striated fragments of local 

 sandstone, showing direct glacial action on the local rocks. 

 In Holmes county, also, finely polished and striated pebbles 

 of corniferous limestone occur, mingled with fragments of 

 granite in the till. These must have been brought from the 

 other side of the water-shed, in the vicinity of Lake Erie, 

 100 miles distant. Near Lancaster, in Fairfield county, there 

 is a granitic bowlder measuring eighteen feet by eleven, and 

 six feet out of the ground. In Ross county, near Adelphi, 

 Chillicothe, and Bainbridge, numerous granitic bowlders were 

 found on the hills from 400 to 600 feet above the valleys, and 

 about 1,200 feet above tide. A hornblendic bowlder five by 

 three by two feet was noted 550 feet above Bainbridge. In 

 Brown, Clermont, and Hamilton counties large granitic bowl- 

 ders abound on the hills down to the very northern edge of the 

 trough of the Ohio. Here, also, are to be found numerous 

 bowlders of jasper conglomerate from the region north of 

 Lake Huron or near the lower end of Lake Superior. The 



