174 



Cincinnati Society of Natural History. 



West of the road more of the Clinton is exposed in the higher 

 ground in the orchard. The top of the Clinton is not shown, having 

 been removed by erosion. Beneath the Clinton on the south side of 

 the hill there is a brownish shaly stone. Though corresponding in 

 position with the Belfast bed, it does not agree with it lithologically, 

 the Belfast bed being usually more massive and united into thicker 

 layers, and not inclined to be shaly. Moreover only 15 inches of 

 these shales are exposed while the Belfast bed is usually four or 

 five feet thick. On the north side of the hill, beneath the level of these 

 shales, and 4 feet beneath the level of the Clinton, occur two feet of 

 thin limestone layers, containing small Lower Silurian bryozoans. Be- 

 low are two feet of heavier limestone courses with Orthis occidentalis 

 fairly abundant. Below the limestones are 4 feet of clay mottled with 

 green and purple, and then two feet of brownish, fine, fissile shales. 

 Then occur perhaps a foot and a half of shale containing large rounded 

 masses, at times 15 inches in diameter which on closer inspection are 

 seen to be chiefly a large nodulated species of some stromatoporoid 

 sponge, and some large species of Tetradium. On the south side of 

 the hill there are no exposures corresponding to the limestone beds on 

 the north side, and there is no mottled clay layer, but over the stromato- 

 poroid bed occur about seven feet of brown shales which must corre- 

 spond therefore not only to the two feet of shales overlying this bed on 

 the north side of the hill, but also to the four feet of mottled clay on 

 the same side, and possibly, at the top, also to the limestone beds. 



On the north side of the hill six feet of brownish fine fissile shales 

 occur under the stromatoporoid bed, and lower down, three feet of 

 blue clay. On the south side shere are no exposures corresponding 

 to the shales, but beneath, instead of three feet of blue clay as on the 

 north, there are about six feet of this clay. 



The layer containing the massive species of Stromatopora and 

 Tetradium is also seen east of the road where exposed by small stream- 

 lets, on the eastern side of the hill. The boulderlike masses, especially 

 those of medium size, are packed closely together. Similar layers 

 occur in Kentucky at a similar horizon, that is near the top of the 

 Lower Silurian, or the upper bed of the Hudson River Group, as it is 

 called in that state. 



In Kentucky however the layer is chiefly characterized by the 

 presence of Columnopora and Tetradium instead of Stro?natopora and 

 Tetradium. As far as can be determined from the published reports, 



