1876.] S7 [Hall 



Modiouiorpha Strophodonta cayuta, 



Orthis impressa, ' ' concava, 



Productella boydii, " perplana, 



The above are from Tioga County. 



HAMILTON GROUP. {Ccident, VIII.) 



Aviculopecten princeps, Modiolopsis modiomorpha, 



Athyris spiriferoides,* Lingula ligea, 



Atrypa reticularis, Phacops bufo,* 



Ambocoelia unrbonata, Rensselaeria ? johanni, 



Belleropbon, Rynconella dotis, 



Clionetes mucronatus, Spirifer fimbricata, 



" coronata, " granulifera, * 



Cryptonella p]anirosti"a, " medialis,* 



Cimitaria recurva, " mucronatus,* 



Discina grandis, " sculptilis, 



" newberryi, Strophodonta concava, 

 Dahnania, " rhomboidalis, 



Fenestella,* Trepidoleptus carinatus, 



Gramnysia, Tentaculites. 

 Ileliophyllum halli. 

 All the above are from Marshall's Falls, Monroe County, Pa. 



Rogers, p. 827, gives the following, also: 



Atrypa aspera, Strophodonta demissa, 



Spirifer congesta, Trematospira hirsuta, 



Strophodonta perplana, 



ORiSKANY SANDSTONE. {Meridian, VIII.) 



Cyrtoceras expansus, Pterinea tax ills, 



Dalmania micrurus, Rensselaeria marylandica, 

 Etonia peculiaris, " ovalis. 



Megambonia lamellosa, " ovoides,* 



Orthis hipparionyx,* Spirifer arenosus,* 

 Platyceras ventricosa, " arrectus. 



All these are from the vicinity of Orbisonia. 



LOWER HELDERBERG. {Pre-MeHdian, VI.) 



Acevalaria, Merista laevis,* 



Alveolites minima, Orthis oblata, 



Alveolites, Pentamerus galeatus,* 



Artylospongia inornata, Rhynconella formosa, 



• Those marked * are mentioned by Rogers. 

 PROG. AMER. THILOS. SOC. XVI. 97. H 



