CLINTON CONGLOMERATES AND WAVE MARKS. 171 
marks are mentioned only from the most southern county— 
Lincoln. This fact should be considered in connection with the 
occurrence of the Oneida conglomerate in Boyle county, another 
very southern county. fe 
Clinton. a, Crab Orchard Shales —These shales reach a maxi- 
mum thickness of 40 feet in Lincoln county. Intercalated among 
them are a few hard, smooth plates of thin limestone. These 
plates, and sometimes the shales, have a curved structure, and at 
times some of the lamine overlap the thinned-out edges of the 
others. In Garrard county they vary from 16 to 25 feet. In 
Clark county these shales are only seven feet thick. They occur 
in Montgomery county, but their thickness is not mentioned. 
The shales appear in Bath county, but form there the lower part 
of the recognized Clinton Group, and will not be discussed in 
this connection. In Marion county the thickness is 20 feet. In 
Nelson county has diminished to two or three feet. 
The presence of the Crab Orchard shales as a representative 
of the Clinton is of interest chiefly in showing the general thick- 
ening of such detrital deposits southward. 
b, Clinton, Proper —Above the Crab Orchard shales, in Mont- 
gomery county, there are rough-bedded heavy limestones. The 
massive layers overlying the shale are somewhat heavier, and in 
one or two places one of them shows a wave-like structure with 
large ridges. Rarely there is a layer of even-bedded stone. 
The same wave-marked layer occurs in Bath county, three feet 
above the shales, and 18 feet above the base of the Clinton. It 
is from 10 to 14 inches in thickness, marked with ridges from 
four to six inches in height and about 26 inches from crest to 
crest. The ridges are not a regular curve, but are somewhat 
sharpened at the top. This wave-marked layer occurs with the 
same persistence and at the same horizon in Fleming and Lewis 
counties. It is probably the layer discovered by Locke in the 
Clinton near West Union, Ohio, to which reference will be made 
later. 
The odlitic iron ore is quite characteristic of the Clinton 
along the eastern side of the Cincinnati anticlinal axis, and its 
