Qian eles, Sik,” 
THE GLACIAL BOUNDARY IN OHIO. 
By Proressor G. FREDERICK WRIGHT. 
The previous volumes of the Ohio State Geological Report have 
made large and interesting additions to glacial geology. No one can 
appreciate more fully than myself the value of the facts collected, and 
of the theories propounded upon the subject by Whittlesey, Newberry, 
Orton, Andrews, Winchell, Gilbert, Read, and others. My work in the 
State is simply supplementary to theirs. Im setting forth the facts 
which I have brought to light, it will be in order, first, to present the 
general evidences relied upon to prove the glacial theory, which are: 
1. THE SCRATCHES UPON THE ROCKS. 
The action of water in rolling gravel and sand loosely over exposed 
rocks polishes both the gravel and the rocks, but can do no more. In 
the northern part of the United States, however, the freshly exposed 
surfaces of rock have numerous parallel strize running over them, and con- 
tinuing across hard and soft portions alike. In some places these striz ex- 
tend for many feet, or even yards, and in size vary from the finest markings 
of a needle-point to grooves or furrows ploughed in the rocks, several 
inches in depth. My colleague, Professor A. A. Wright, describes a 
groove, on Kelley’s Island, in hard limestone rock, known to be more 
than two hundred feet long, and from two to six feet deep. 
The general parallelism of this striation demonstrates that it could 
not have been made by icebergs, though, as might be expected, the 
direction of the strive varies greatly in different portions of the country. 
In the eastern part of New England the direction is considerably east 
of south. In the vicinity of the Connecticut and Hudson rivers the direc- 
tion is south, while toward the western end of Lake Erie the striz run west 
of south, though there is a set of strie, even here, running at right angles. 
In general they may be said to radiate from a center situated near the 
south end of Hudson’s Bay. The larger valleys modified the motion of 
the ice-stream somewhat; but usually the movement was continental, 
