PEALE.] 



RESUME MESOZOIC ROCKS JURA-TRIAS. 



627 



Meekoce ) 'a s grac i lit a tls. 

 Meekoceras m uslibaclianus. 

 Arcestes cirratus. 

 Arcestes sp. u ? 

 Arcestes sp 3. 

 A vicu Jopecten peaJei. 

 Undetermined concliifers. 

 HJumicrotis curta. 

 Undetermined concliifers. 



AricuJopecten idalioensis. 

 JEJumiorotis curta. 



Terebratida augusta. 

 Terebratu la semisimplex. 

 Ariculopecten idalioensis. 

 Undetermined concliifers. 

 Gervillia sp. ? 



AricuJopecten idalioensis. 

 Ariculopecten rectus. 

 Terebratida augusta. 



Av iculopecten peaJei. 

 Gervillia sp.? 



Aviculopecten idalioensis ? 

 Eu microtis curta. 



Ostrea strigiJecuJa ? 



Eidge north of Station 66, south of 

 John Gray's Lake. 



) Station Q6, south of John Gray's 

 l Lake. 



Eidge south of Station 6Q. 



£ Station 70, west of Blaekfoot Eiver. 



) Eidge north of Station 56, Salt 

 ( Eiver Eange. 



il 

 i Lake Plateau. 



) Near Station 100, north end of Bear 



\ West of Station 108. 



Pentacrinus asteriscus was found nowhere associated with Meekoceras or 

 Eum icrotis, and the latter was never by us found in the strata above 

 the Bed Beds. The following, as will be seen from the list just giverj, 

 were the associated fossils with Pentacrinus asteriscus : 



Camptonectes belJistriatus. 

 Ostrea strigilecida. 

 Trigonia sp. ? 

 Tancredia sp.? 

 Volsella sp. 1 

 Myalina sp. ? 

 Myacites sp. ? 

 Neritina sp.? 

 Undetermined concliifers. 

 Undetermined gasteropods. 



These are all Jurassic forms ; and 1 believe the only instance in which 

 P. asteriscus has been found associated with Triassic forms is the one 

 mentioned in the reports of the Fortieth Parallel Survey,* in which it is 

 stated that it was found associated with what are regarded as unmistak- 

 able Alpine Trias fossils and also a spirifera, a palaeozoic type. Mr. Em- 

 mons says :t " It should be stated also that these disks of Pentacrinus 

 found in the Dun Glen limestone vary somewhat from the type speci- 

 mens, and are all of larger size, reaching one-fourth of an inch in diam- 

 eter, while those of Jurassic age scarcely reach one-fifth of an inch. Pro- 



* Descriptive Geology, Vol. II, p. 711 ; Systematic Geology, Vol. I, pp. 279, 280. 

 tDeserii>tive Geology, Vol. II, p. 711. 



