76 



INVERTEBRATE PALEONTOLOGY. 



[WHITE. 



have been observed while making the collections in the field and also dur- 

 ing- their more critical investigation in the laboratory. Some of these facts 

 have an interesting bearing upon the characteristics of the fossil faunae of the 

 periods which the collections represent, the relation of those faunae to each 

 other, and to both fossil and recent faunae of the whole Plateau Province as 

 well as those of other regions. 



For the purpose of facilitating reference to the groups of strata which 

 have furnished the fossils, the following table is introduced. The classifi- 

 cation of the formations used in this report is, for the geological ages and 

 periods, the same as that of Dana's Manual of Geology (1874,) and for the 

 groups of strata of the Pleateau Province, that of Professor . Powell in his 

 section of the Uinta Mountain region. 



Table of the formations of the Uinta Mountain Region. 



Thickness iu feet. 



Groups. 



Periods. 



1,800. Brown's Park Group 



2,000. Bridger Group 



500. Upper Green River Group. ^ Tertiary [ Cenozoic. 



800. Lower Green River Group . 



3,000. Bitter Creek Group 



1,800. Point of Rocks Group 



1,800. Salt Wells Group . 



fc) AAn a i i n i n ' Cretaceous . . 



2,000. bulpliur Creek Group . . - - 



500. Henry's Fork Group 



1,200. Flaming Gorge Group > Jurassic / Mesozoic. 



> * 



1, 1 00. White Cliff Group 



1,100. Vermilion Cliff Group \. Triassicl 



1,800. Shinarump Group 



1,000. Upper Aubrey Group. 



1,000. Lower Aubrey Group 



r^n ^. i -ITT n /-M r Carbomterous . > Carbomterous. 



2,000. Red Wall Group 



460. Lodore Group 



