An Account of the Middle Silurian Rocks of Ohio and Indiana. 187 



specimens of some species of Encrinurus. Beneath the Tetradium 

 layer was a 3 inch course of a medium grained limestone, through 

 which some animal from the layer above, had bored vertical tubes, 

 later filled up by a finer limestone material. 



The massive Tetradium so close beneath the Clinton rock, recall 

 the similar layer at Morris's Hill, half mile north-east of Dodd's station, 

 which at that place, however, occurs about 12 feet below the base of 

 the Clinton. 



34. Fair Haven. — Crossing the bridge north of Fair Haven, 

 ascending the creek along its western side, as far as the first culvert, 

 and then going up a small branch which enters from the west, until it 

 has been traced to an open field beyond the woods, an exposure of 

 the Clinton is found. The Clinton is here at least 7% feet thick. 

 Beneath the Clinton is found a layer of a finely stratified white solid 

 rock, more sandy than any other rock at this locality; its thickness is 

 almost 1 foot. It contained a specimen of Strophomena alternata. 



Beneath this hard rock is found a green shaly clay about iy 2 feet 

 thick. Farther up the creek the upper part of this clay assumes the 

 characters of a hard rock and contains Ortliis occidentals. Under the 

 clay layer occurs a limestone, 1 foot thick. This limestone, especially 

 in the bed of the stream, very much resembles lithologically the Clin- 

 ton, and with this it was formerly confused by the writer. But it 

 contains that Lower Silurian form of OrtJiis biforata which has wide 

 plications; also OrtJiis occidentalism Strophomena alternata, Strophomena 

 alternata var. fraeta, and Strophomena filitexta. Under this limestone is 

 found a layer of blue shaly clay about 8 inches thick. This contains 

 great growths of Stromatoporoid fossils in places. Underneath is a 

 layer of limestone 8 inches thick, and this in turn is underlaid by 2 

 feet of a blue shaly clay. From a study of these later observations it 

 will be seen that no space is left for the existence of the Medina at this 

 place. What was formerly considered the Medina now turns out to 

 be without doubt the Lower Silurian. 



