420 Annals of 'jhe Carnegie Musfx'm. 



Nucula sp. 

 Gastropoda. 



Platyceras sp. 



Strophostyliis rcincx ^^'hite. 

 "This fauna is plainly Upper Carboniferous (Pennsylvanian) in 

 character, and seems to be somewhat closely related to the Hermosa 

 formation of the San Juan region, Colorado, as described by Girty." 

 Sheep Aloiintain. — This mountain lies to the south and west of Old 

 Baldy Mountain. Here several years ago I found a few crinoids 

 which were determined by Girty as Platycrhuis l>ozei?ianensis, Rhodo- 

 crinus doi/glassi and Actinocriniis ? sp. This is Lower Carboniferous. 

 Above these beds there is a considerable thickness of crystalline lime- 

 stone full of links of crinoid stems and fragments of Brachiopods. I 

 found no good fossils here. This perhaps is Upper Carboniferous. 



Tobacco Root Mountains. — In the summer of 1900 Prof. E. H. 

 Murray and myself, while collecting for the University of Montana, 

 ascended the Tobacco Root Range and traversed about 25 miles of 

 its crest. The rocks examined here were chiefly Carboniferous and 

 Jurassic. Here we get the upper members of the former, which are 

 just beneath the latter. Here the upper part of the Carboniferous 

 is a peculiar formation principally limestone wiih red stains. In it 

 there were many fossils. In one cliff near a little red lake I made a 

 considerable collection which is now in the University of Montana. 

 I think this is upper Carboniferous but the fossils have not been de- 

 termined. It will be interesting to know what relation this fauna 

 beats to that from the upper Carboniferous quartzytes at Ziegler's 

 Canon, a list of which I give later. In the bedded sandstones which 

 I found overlying the Carboniferous here there were Jurassic inverte- 

 brates and in a layer of clay were many bones of large Dinosaurs. 

 There certainly is not any great thickness of Carboniferous quartzyte 

 here. 



Sno7c> Crest Range. — This is a high mountain ridge which has a 

 rather unusual trend for a mountain range of this region. Its direc- 

 tion is north of northeast and south of southwest. Its height and 

 sharpness and the extending of the Tertiary beds high on its western 

 flank gives one the impression that it is a comparatively new uplift. 

 What surprises the geologists who have examined the Palaeozoic rocks 

 of the surrounding region is the entirely different character and ap- 

 pearance of the rocks here. Instead of the gray, more or less brown- 



