122 



GEOLOGY OF THE THIRD DISTRICT. 



No. 4, is another species, which may be considered as the type or characteristic of the 

 division, and thence may properly be termed the Medial atrypa (A. medialis), the others 

 diverging or converging from this middle point. Size natural. 



No. 5. Punctulated stropbomena (S. punctulifera). 



No. 6. R&diated stropbomena (S. radiata). 



There are two species of stropbomena in this rock, which are very numerous, and by which 

 the rock may in many of its localities be readily determined. They abound through its range 

 in Herkimer county, associated with the Smooth atrypa, the Medial atrypa, and the Depressed 

 stropbomena, which latter reappears in this rock from the Niagara group, not having been 

 seen in the intermediate ones in the district. The internal impression of the two fossils in 

 question are given, by reason of their greater abundance than the shells themselves, and espe- 

 cially as these latter will vrith certainty be figured in the Report on the Fossils of the State. 



The following list presents all the fossils belonging to this rock, which have been identified 

 and named by Mr. Conrad up to this time : 



Testacea, or Shells. 



Atrypa resembling the concentrica of the 



Hamilton group. 

 Atrypa prisca. 

 Atrypa inflata. 

 Platyceras ventricosum. 

 Platyceras gebhardii 



Delthyris macropleura. 

 Delthyris pachyoptera. 

 Delthyris granulosa. 

 Delthyris bilobata. 

 Orthis resembling the resupinata. 

 Stropbomena pimctulifera. 

 Stropbomena rugosa (the dep 

 Stropbomena radiata. 

 Stropbomena indentata. 



i 



Calceola plicata. 

 Conularia quadrisulcata. 

 TentacuUtes scalaris. 



CORALEA, OR CoRALS. 



Calamopora favosa. 



Asaphus plcuroptyx. 

 Asaphus nasutus. 

 Ascidopsis tuberculatus. 



Crustacea. 



Acanthaloma, not determined 

 Dicranurus, ditto. 



