RIPPLES OF THE BEDFORD AND BEREA IN OHIO 265 



they are retarded more in the shallower portions, so that by a 

 process of wave-refraction they are soon brought into a line roughly 

 parallel with the contour lines of the bottom. And the contour 

 lines of the bottom, on all gently sloping coasts, are nearly parallel 

 to the shore line. 



The conclusion seems to be warranted that the persistency of 

 direction of the ripples of the Bedford and Berea indicates the 

 prevailing direction of the water waves which formed them, and 

 that this in turn was controlled, either by a shore line or water 

 so shallow as to bring the waves into adjustment parallel to this 

 shore line, or, if it was only shallow water control, to the contours 

 on the sea floor. The shales of the Bedford clearly indicate that 

 there must have been an open sea to the northeastward. Toward 

 the southward the sediments become more sandy and on the whole 

 coarser (the sandstone becomes but slightly coarser but increases 

 very much in relative amount). From this we conclude that 

 either a shore line or shoal water lay toward the southward with 

 decreasing depths of water in that direction sufficient to cause 

 wave refraction. This shore line or the contour of the bottom 

 must have been parallel to the ripple direction, that is, it must 

 have extended in a northwest-southeast direction. 



Probably the sea in which these sediments accumulated was 

 of moderate depth, sufficiently so that sedimentation would be 

 continuous. The only evidence of occasional currents which were 

 strong enough to erode locally is found in the middle and upper 

 part of the Berea in central Ohio where the ripples are much 

 less numerous. Quite probably it may have been sufficiently 

 shallow and so well inclosed and protected that currents and 

 waves of oceanic proportions could not develop. 



CHANGE IN RIPPLE DIRECTION IN PASSING FROM NORTH TO SOUTH 



A brief survey of the map suggests that the directions along the 

 Ohio River tend more nearly east and west than they do farther 

 north. The number of directions occurring within each five 

 degrees has been plotted in four areas. This brings out the fact 

 that there actually is a swing in the direction of the majority of 

 the ripples to more nearly east and west in southern Ohio. In 



