STRATIGRAPHY OF OHIO WAVERLY FORMATIONS 759 



The deposits which distinguish this facies differ greatly from 

 those in the two sandstone and conglomerate facies just described. 

 They consist of alternating beds of exceedingly regular sandstone 

 and shale. The sandstones are usually from 6 or 8 inches to 18 

 inches in thickness, although they exceptionally attain 4 or 5 feet; 

 they are very uniformly fine grained, blue-gray in color when 

 unweathered, and persistently uniform in thickness for considerable 

 distances. The shales not uncommonly are mere partings between 

 these beds, but they may equal or exceed the sandstone beds in 

 thickness. At McDermott the thin sandstone and shale beds are 

 known to hold their characteristics individually over almost a 

 square mile. The shales are thicker at the bottom and at the top 

 and the persistent occurrence of a considerable amount of red shale 

 in the lower part is one of the characteristic features of this facies 

 and an unusual one in the Waverly. 



The upper surface of each stratum of sandstone is covered by 

 Spirophyton markings, the tubes of which penetrate downward 

 through the upper 4-8 inches in infinite numbers. The under 

 surface of each sandstone is usually traversed by many raised lines 

 and elongate rootlike ridges in various degrees of prominence which 

 are merely the casts made by the sand settling in the scratched and 

 gouged upper surface of the underlying shale partings. These 

 structures indicate a peculiar cycle of events that was repeated 

 many times during the accumulation of the deposit: (i) accumula- 

 tion of sands to a thickness of a foot or two; (2) period of quiet 

 and invasion of the ■ sandy floor by myriads of fixed worms (if 

 Spirophyton is correctly interpreted as a worm tube) ; (3) deposi- 

 tion of a thin bed of clay mud and extermination of the worms; 

 (4) intervention of some agent, probably bodies floating or trailing 

 in shallow water, which scratched the muds but never, so far as 

 observed, to a depth of over an inch; this completed the cycle 

 and sands were again laid down. This was repeated many times 

 but it is more striking in the lower part of the sandstones, where the 

 shales are reduced to mere partings. 



The deposit is marine, as is shown by the occasional finding of 

 a sandstone bed which differs from the others only in the presence 

 of a normal marine fauna of brachiopods, gastropods, cephalopods. 



