232 CARBONIFKROUS FORMATIONS AND FAUNAS OF COLORADO. 



ill phirc, anil occur in tlic I'orni of intcriuil casts. Their probable horizon is the 

 Bollcropiion liinostoiie, at the top of the Upper Aubrey group. The identification 

 is by C. A. ^^'ilito, who refers to the specimens on payo 92 of l^owelTs I'inta 

 ^Mountains volume. 



LopJiiijiIiijII luii jirofiiiKliiiii and RhoiuhopofiL lepidodendroides are from station 

 2191, overloolving Yampa River. The locality of thi.s collection is not very definite, 

 and the horizon is unknown, but without much doubt is lower than the Bellerophon 

 limestone, almost certainly somewhere in King's Upper Coal Measure series. I can 

 not find that these fossils have ever been referred to in literature. 



Priniiiopojut friangulata and Spiriferina hentuckyenaiii are from Yampa Plateau, 

 northwestern Colorado (station 2330). The identification of Pr'mnopmxt triungulata 

 is that of C. A. White, who figured this specimen in 1880." I can not find that this 

 occurrence has been elsewhere mentioned. His figui-es, somewhat enlarged, are 

 reproduced on PL I of the present volume. He states that the horizon is the 

 middle division of the Carboniferous series, which he cori'elates with the Lower 

 Aubrej' group. Unless I am mistaken in supposing the Uinta sandstone to I'epre- 

 sent the Maroon formation, this horizon is not that called Middle. Cai-boniferous b}^ 

 the other Hayden geologists, but is considerably higher. These fossils are inadequate 

 not only to indicate more than the Upper Carboniferous age of the rocks furnish- 

 ing them, but also to supply a means of correlation with other sections in Colorado. 



GRAND EIVER REGION. 



We have Carboniferous collections from a number of points in the Grand River 

 region of Colorado, but they are in most cases quite scanty. The most complete 

 collections are. those made at Glenwood Springs, but, unfortunately, few of these 

 can be satisfactorily located in the standard geologic section. It is probable that 

 they came from the Weber limestone or its equivalent. Our collections are 7 in 

 number, and contain a fauna of 25 species. The distribution of this fauna by 

 localities can be seen in the accompanying table: • 



au. S. Geol. Geog. Surv. Terr., Cont. to Pal. (author's edition), 1880, p. 131, pi. 33, figs. 3n-3i!. 



