+k ie 
274. Cincinnati Society of Natural History. 
Mountain region, where it presents the usual variety of lithological char- 
acters. In some localities it is a conglomerate of more or less water-worn 
pebbles, mostly whitish crystalline quartz, and varying from 2th to 
4 inches in diameter, cemented together with a silicious paste. Some 
of the pebbles are scarcely worn, while others are quite smooth. At 
other places, the sandstone contains micaceous particles, and often 
calcareous matter, and sometimes seams occur from 2 to 4 inches in 
thickness, almost entirely composed of Obolella and Linguloid shells. 
This Group contains ripple marks, wave lines, mud cracks, animal 
tracks and worm burrows, but such things occur even to the present 
day, though we distinguish the Potsdam tracks by the names Climach- 
tichnites and Protichnites, and the burrows by Scolithus, a generic 
name, which is also applied to fossils in the Hudson River and Medina 
Groups. And there are Veretts, Myrianites, and Nemapodia, of un- 
certain affinity. 
In the vegetable kingdom, we have Palewophycus, which occurs in 
the Calciferous, Hudson River, Medina, Clinton, and as high as the 
Coal Measures; Buthotrephis, which occurs in the Calciferous, Trenton, 
Utica Slate, Hudson River, Clinton, and Waterlime Groups; Arthraria, 
which occurs in the Trenton and Hudson River; and Hophyton and 
Cruziana which are peculiar to it. 
The Protista are represented by Archeocyathus, which occurs in the | 
Calciferous, and Protocyathus which is peculiar to it. | 
The Polypi are represented by Dendrograptus; which occurs in the 
Quebec, Utica Slate, Hudson River, and Niagara Groups; and Old- | 
hamia, which occurs in the Trenton. 
The Echinodermata are represented only by Hocystites above men- | 
tioned. } 
The Brachiopoda are represented by Orthis, Obolella, Discina and — 
Lingula, as above mentioned; by Crania and Orthisina which occur in 
the Calciferous, Trenton, Hudson River, and other Groups as high as 
the Coal Measures; by Leptena which occurs in the Trenton, Utica : 
Slate, Hudson River, Clinton, Lower Helderberg, and Oriskany Groups; 
by Camarella, which occurs in the Calciferous, Quebec, Chazy, Black 
River, Trenton, Hudson River, and Clinton Groups; by Lingulella 
and Trematis, which occur in the Trenton and Hudson River: by Lin- 
gulepis, which occurs in the Chazy; by Acrotreta and Iphidea which 
occur in the Quebec; and by Kutorgina, which alone is peculiar to it. 
The Pteropoda are represented hy Theca, as above mentioned; by — 
Hyolithes, which extends to the Hamilton, and by Hyolithellus, which | | 
is peculiar to it. : | 
