PORTAGE AND CHEMUNG FORMATIONS OF MARYLAND 339 



These faunas are to be traced throughout most of the area discussed. 

 Their relations are indicated upon the accompanying chart. Their 

 constancy of composition, shown by their predominating species, and 

 their occurrence at the same relative position in the various sections, 

 seem to indicate that they are recognizable units, and that they pre- 

 serve their integrity throughout the area discussed. If we assume that 

 the species occurring in the same relative position in the various sec- 

 tions belong to one fauna, the lists in Tables I and II may be taken as 



TABLE II 



Species Observed in the Spirijer mesacostalis Fauna 



Occurrence in 



Hamilton 



Portage 



New York P'nsylvania 



Atrypa reticularis (L.), r 



Camarotoechia congregata (Conrad), aa 



Camarotoechia eximia Hall, r 



Camarotoechia sappho Hall ( ?), r 



Cyrtina hamiltonensis Hall, c 



Chonetus scitulus Hall 



Productella lachrymosa (Conrad), a 



Lingula sp 



Spirifer mesacostalis Hall, aa 



Spirifer marcyi Hall var 



Tropidoleptus carinatus (Conrad), aa 



Goniophora glaucus Hall 



Goniophora sp 



Goniophora n. sp 



Cypricardella bellistriata (Conrad) 



Cypricardella gregaria (Hall) 



Nuculites oblongatus Conrad 



Leptodesma sp 



Bellerophon maera Conrad 



Bellerophon sp 



Bellerophon n. sp 



Bellerophon n. sp. approaches B. acutilira Hall 



Cyclonema concinnum Hall 



Cyclonema hamiltoniae Hall 



Coleolus tenuicinctus Hall 



Euomphalus laxus Hall 



Murchisonia sp 



Murchisonia n. sp 



Pleorotomaria itys Hall 



Pleurotomaria n. sp. resembles P. rotalia Hall. , 



Platyceras sp 



Platyceras n. sp 



Orthoceras sp 



Trochoceras n. sp 



Phacops rana Green 



Bryozoa, 2 species 



