168 



GEOLOGY OF THE BLACK HILLS. 



excepting a single crocodilian bone found in the Uinta Mountains. Among 

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

 conifers, and cycacls, bearing a great similarity to the fauna of the Trias ; 

 but in America no undoubted Jurassic plants have yet been found. The 

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

 him 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 1876. Those marked (*) have been obtained from the Black 

 Hills: 



* Ammonites cordiformis. 

 * Ammonites Henryi. 

 Astarte arenosa. 



* Astarte fragilis. 



* Astarte inornata. 

 *Asterias dubium. 

 *Avicula mucronata. 

 *Belem,nites densus. 



* Camptonectes bellistriatus. 



* Camptonectes extenuatus. 

 Camptonectes pertenuistriatus. 

 Camptonectes platessiformis. 

 Camptonectes stygius. 



*Dosinia Jurassica. 

 *Gervillia recta. 



* Grammatodon inornatus. 

 Gryplicea calceola. 

 Lima occidentalis. 



*Lingida brevirostris. 

 * Lioplacodus veturnus. 



Modiola subimbricata. 

 *Myadtes Nebrascensis. 



Myacites subcompressa. 



MyopJioria lineata. 

 *Mytilus Whitei. 



Natica Lelia. 

 *Necera longirostris. 



Neritina Powelli. 

 *Ostrea Engelmanni 



Ostrea procumbens. 

 *Qstrea strigilecida. 

 *Pecten Newberryi. 

 *Pentacrinus asteriscus. 

 *Pliolodomya humilis. 



Pholadomya Kingii. 

 *Planorbis veturnus. 

 *Pleuromya Newtoni. 

 *Protocardium Sliumardi. 

 * Psammobia prematura. 

 * P seudomonotis curia. 

 *Pseudomonotis orbiculata. 



Rhynclionella gnatlwpliora. 

 *Bhynchonella myrina. 



Septocardia carditoidea. 



Septocardia typica. 

 *Saxicava Jurassica. 



