168 



GEOLOGY OF THE BLACK niLLS. 



cxceptiii*^ a single crocodilian bone found in the Uinta Mountains. Among 

 plants the European Jura has yielded an abundance of remains of ferns, 

 conifers, and c}cads, bearing a great similarity to the fauna of the Trias ; 

 l)ut in America no undoubted Jurassic plants have yet been found. The 

 plants from the Moqui region described by Dr. Newberry are regarded by 

 liiiM as not distinctive enough to decide whether they are Triassic or Juras- 

 sic, though they are of Mesozoic types and probably Jurassic. 



The following list contains the invertebrate species that have been 

 described from the Jura of the Rocky Mountain region up to and including 

 the year 187G. Those marked (*) have been obtained from the Black 

 Hills: 



* Ammonites cordiformis. 



* Ammonites Henryi. 

 Astarte arenosa. 



*Astarte fragilis. 

 '''Astarte inornata. 

 *Asterias dubium. 

 *Avicula mucronata. 

 *Belemnites densus. 



* Camptonectes bellistriattcs. 



* Camptonectes extenuatus. 

 Camptonectes pertenuistriatus. 

 Camptonectes ijlatessiformis. 

 Camptonectes stygius. 



*Dosinia Jurassica. 

 *Gervillia recta. 



* Grammatodon inornatus. 

 Gryphcea calceola. 

 Lima occidentalis. 



*Lingula hrevirostris. 

 *Lioplacodus veturnus. 



Modiola suhimbricata. 

 *3Iyacitcs Xebrascensls. 



Myacites subcompressa. 



Myoplwria lineata. 

 *MytUus Whitei. 



Natica Lelia. 

 *Necera longirostris. 



Neritina Powelli. 

 *Ostrea Engelmanni 



Ostrea procumbens, 

 *Ostrea strigilecula. 

 *Fecten Newberryi. 

 *Pentacrinus asteriscus. 

 *Pholodomya humilis. 



Pholadomya Kingii. 

 *Planorbis veturnus. 

 *Pleuromya Newtoni. 

 *Protocardiiim /SJimnardi. 

 *Psammobia prematura. 

 *Pseudomonotis curia. 

 *Pseudomonotis orbiculata. 



Phynchonella gnathopJiora. 

 *Bhynchon ella myrina. 



Septocardia carditoidea. 



Septocardia typica. 

 *Saxicava Jurassica. 



