CARBONIFEROUS SYSTEM 429 



Derbla 1 s\3. Euphemussp. 



Avicitlipecten occidentalis. Bellerophon crassus. 



Aviculipecten 2 sp. Soleniscus hallanus ? 



Uyulina permiana ? MurcMsoiiia aff. M. tcrrehra. 



Pleiirophorus ? sp. Tainoceras occidcntalc. 



ScMzodus sp. " Nautilus sp. 



ScJiizodus meekanus. Orthoceras sp. 



Patellostiuin montfortiaimiim . Ammonoid indet. 



Doctor Girt)' regards this fauna as very closely related to that of tlie 

 upper part of the Pennsylvanian division in the Kansas section. 



There were found in limestones in the middle of the formation, on 

 slopes of Laramie mountain 20 miles north of Laramie, Prodnctus semi- 

 reticulatus, P. cora. Archaocidaris sp., and Pinna sp. ; in the upper lime- 

 stone 2 miles east of Laramie, BellcropJion sp. ; in the lowest limestone, 

 on the mountain crest 6 miles east of Laramie, Mekella striatic ostata, 

 Spirifer cameratus, ? and Bellerophon sp. ; in the iipper limestone 9 miles 

 southeast of Laramie, abundant Orthotetes sp., and in the lower lime- 

 stones, at head of Gilmore canyon, 9 miles southeast of Laramie, Spirifer 

 cameratus. These were determined by Dr 6. H. Girty, and are all Penn- 

 sylvanian. 



Mr Arnold Hague, of the 40th Parallel Survey,^" reported distinctive 

 Pennsylvanian fossils from localities on Sybille creek, Chej^enne pass, and 

 at a point 5 miles northwest of Sherman. The two latter are southeast 

 of Laramie. At the first place the fossils occurred in 200 to 300 feet 

 of limestones about 200 feet above the granite, the second locality was at 

 about the same horizon, and the third was the basal limestone lying on a 

 thin mass of lower red sandstones. 



In the lower portion of the limestone of the Casper formation, in Twin 

 Squaw butte, 17 miles northeast of Iron Mountain station, the following 

 species were obtained: Chonetes mesolohus, Productus cora, Squamularia 

 perplexa, Seminula ? sp., and some ostracods. 



Hayden" reported Athyris subtilita from cherty limestone of the Cas- 

 per formation on Boxelder creek, and Hemipronitcs crassus. Productus 

 nodosus, and Myalina pevattenuata from the blue limestone over very 

 cherty limestone on La Prele creek. Spirifer centronatus and Strapa- 

 rollus utahensis, obtained from cherty limestone on red shale at base of 

 Casper formation, 7 miles northwest of Marshall, are Mississippian forms 

 probably indicating basal Amsden beds, which Ijelong in that division. 



'" (Jeological Survey of the 40th Parallel, vol. 2, Descriptive Geology, pp. 76-77. 

 "1 Fourth Annual Report, U. S. Geological Survey of the Territories, part 1, 1871, pp. 

 23-25. 



