298 
GEOLOGY OF THE FOURTH DISTRICT. 
144. 
There is an oblique line of fracture, as represented, ascending to the left; and this is a 
common circumstance attending nearly all these fractures or dislocations. It will be per¬ 
ceived that the amount of dislocation is never so great as to produce any evidence upon the 
surface ; and these localities are only interesting as showing the influence of causes which, 
at other points, have wrought such mighty changes. In every instance which I have observed, 
the direction of this force is at right angles to the line of dip, or in the direction of the out¬ 
cropping edges of the strata. It is in the same direction mainly that the great undulations 
extend, and both are probably due to the influence of the same agency. 
Besides these fractures and dislocations, others appear to have a local origin, such as the 
downheaves along the line of dip in the limestones. In tracing the limestone southward in 
Seneca county, we find its dip often greater than the average of the strata in other places ; 
and after its disappearance, we again find the same layers rising to the surface still farther 
south. Although the soil covers the surface, and the absolute fracture is not seen, yet it 
doubtless exists, and is probably due to the falling down of the layers on the north, from the 
removal of the soft marls of the Salt group below.* 
The same layers appear at the successive points 1, 2, 3, or at least they are so precisely 
similar that there is no possibility of distinguishing them ; and we farther know, that if the 
thickness of the rock is estimated from adding all these successive outcrops, it w'ould be 
greatly increased over the same in other places. 
See illustration, page 163. 
