TROPIDOLEPTUS CARINATUS IN CHEMUNG FAUNA 349 



some of the softer beds leaves some uncertainty regarding the 

 exact thickness of the section. 



It is with the next fauna in the section that this paper is chiefly 

 concerned. This fauna appears after the bluish-gray sandy shales 

 and very thin sandstones have given place to very hard thin-bedded 

 sandstones as the dominant lithologic characteristic of the section. 

 In beds of this kind in division g of the section occurs the first 

 appearance of the Chemung fauna. The following is a list of the 

 species collected from this horizon : 



FAUNULE g, MOUNTAIN GROVE, VA. 



Productella sp c 



Camarotoechia cf . congregata c 



Leiorhynchus sp c 



Atrypa spinosa c 



Rhipidomella impressa r 



Rhipidomella cf . penelope • r 



Schizophoria tioga c 



Ambocoelia umbonata c 



Schuchertella chemungensis r 



Delthyris mesacostalis c 



Spirifer medialis c 



Reticularia fimbriata r 



Tropidoleptus carinatus a 



My tilarca chemungensis r 



Modiomorpha sp r 



Nuculites cf . oblongatus r 



Cyclonema sp. 



The stratigraphic position of this fauna several hundred feet 

 above a typical Portage fauna shows plainly that it lies far above 

 the Hamilton horizon. Its association with Schizophoria tioga 

 and Mytilarca chemungensis indicates that it is here associated with 

 a Chemung fauna. In the next division of the section above this 

 we find Spirifer disjunctus and other well-known Chemung fossils 

 as shown in the following list from division h of the section : 



FAUNULE h, MOUNTAIN GROVE, VA. 



Aulopora sp r 



Chonetes scitula c 



Productella hirsuta c 



