Douglass: Geology ok Sori hwfstkrx ^roxr.WA. 41*1 



stained, rather thinly stratified limestones of the Lower Carboniferous 

 of the Bridger, Ruby, Madison, and the Tobacco Root Ranges, which 

 are usually overlaid by gray massive or more thickly bedded lime- 

 stones, we have not less than 1,500 feet of a uniformly colored black 

 limestone with alternations of thinner and thicker strata. This is in 

 turn overlaid by heavy (juartzytes. In the rock beneath this I found 

 no fossils, but it is almost identical in appearance with the Cambrian 

 elsewhere. There are fossiliferous strata through the entire thickness 

 of the formation. The lists are given in Mr. Girty's communication, 

 which is quoted farther on. 



Sc^^i^'^c' Creek. — In one locality on a branch of Sage Creek which 

 flows into Red Rock Creek below Lima a collection was made. This 

 is where the stream has cut a ravine through a portion of the Carbo- 

 niferous series. It is about twenty miles farther west than the place 

 where the fossils were collected on the Snow Crest Range. 



Rocky Mountains. — Main Divide south of Red Rock Lake. Here 

 the Palaeozoic rocks are more nearly horizontal than is usual. The 

 mountains here stand up like a great wall or tableland. The northern 

 part is made up of timbered slopes, slides of broken limestone, and 

 perpendicular cliffs. The rock is in thin and thicker layers. The 

 fossils that were found there were poor. 



I now give the lists of fossils sent me by IMr. Girty with the por- 

 tion of the letter which gives his views as to the horizons repre- 

 sented. 



The following species have been identified. 



I. Spring Canon, Ruby Mountains, about fourteen miles west of \'ir- 

 ginia City, near Laurin, Montana. 



CyatJiocriniis sp. 



Taxocriniis sp. 



Actinocriniis sp. 



Platycrinus bozenianensis. 



Platyct'iniis n. sp. 



Rhodocriniis doiig/assi ? 



Rhodocrinus hozemancnsis. 



Poteriocriuus n. sp. 



ArchcBocidaris sp. 



Chonetes ornatiis. 



Chonetes loganensis. 



Prod net us sea briculus. 



