PEALE.] 



KESUME MESOZOIC EOCKS JUEA-TEIAS. 



627 



MeeJcoceras gracilitatis. 

 Meekoceras mushbachanus. 

 Arcestes cirratus. 

 Arcestes sp.? 

 Arcestes spJ 

 Aviculopecten pealei. 

 Undetermined concM/ers. 

 Eumicrotis curta. 

 Undetermined concMfers. 



Aviculopecten idaJioensis. 

 Uumiot'otis curta. 



Terehratula augusta. 

 Terehratula semisimplex. 

 Aviculopecten idalwensis. 

 Undetermined concMfers. 

 Gervillia sp. ? 



Aviculopecten idalwensis. 

 Aviculopecten rectus. 

 Terehratula augusta. 



Aviculopecten pealei. 

 Gervillia sp. 1 



Aviculopecten idalwensis f 

 Eumicrotis curta. 



Ostrea strigilecula f 



Eidge north of Station 66, sontli of 

 Jolin Gray's Lake. 



) Station 6Q, soutli of Jolin Gray's 

 j Lake. 



• Eidge soutli of Station G6. 



Station 70, west of Blackfoot Eiver. 



) Eidge north of Station 56, Salt 

 ) Eiver Eange. 



) Near Station 100, north end of Bear 

 ) Lake Plateau. 



|westof Sta,tionl08.' 



Pentacrinus asteriscus was found nowhere associated with Meekoceras or 

 Eumicrotis^ and the latter was never by us found in the strata above 

 the Eed Beds. The following, as mil be seen from the list just given, 

 were the associated fossils with Pentacrinus asteriscus : 



Gamptonectes hellistriatus. 

 Ostrea strigilecula. 

 Trigonia sp. ? 

 Tancredia sp. ? 

 Volsella sp. ? 

 Myalina sp. f 

 IlyaciteStB]).'^ 

 Weritina 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 Alx)ine Trias fossils and also a spirifera, a palteozoic type. Mr. Em- 

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

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

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

 eter, while those of Jiu-assic age scarcely reach one-lifth of an inch. Pro- 



"^ Descrii>tive Geology, Vol. II, p. 711 ; Systematic Geology, Vol. I, pii. 279, 280. 

 t Descriirtive Geology, Vol. II, yi. 711. 



