418 Annals of the Carnegie Museum. 



"Old Baldy, head of Alder Gulch, Montana, Field No. 133. 



Favosites sp. ind. 



Platycrimis sp. ind. 



Fenestella sp. 



Ptilopora sp. 



Productus ga/Iafiiie/isis Girty. 



Productus Icevicosta White. 



Athyris lamellosa L'Eveille. 



Proetus peroccidens Hall and Whitfield. 



Spirifer centronatus AVinchell. 

 "Three of these species: Productus gallatinensis, P. l(Pvicosfa and 

 Proetus peroccidens are among the commonest species of the Madison 

 limestone of the Yellowstone National Park, and may be considered as 

 characteristic of the Mississippian, though Productus gallatinensis has 

 been found in the Hermosa formation (Pennsylvanian) of Colorado. 

 Athyris lamellosa, though rare in the Madison limestone, seems to be 

 confined to the Mississippian. Spirifer centronatus is a characteristic 

 LoAver Carboniferous form. 



"Baldy Mountain, Montana, Field No. 134. 



Productus cora d'Orbigny. 



Productus sp. 



Spiriferina spinosa Norwood and Pratten. 



Hustedia niormoni Marcou. 



Myalina cuneiformis Gurley. 



Cleiothyrus sp. 



Athyris sp. 



Proetus cf. P. peroccidens. 

 "Judging from the presence of Hustedia morvioni, Productus cora 

 and a Spiriferina of the spinosa type, this faunule belongs to the 

 Upper Carboniferous, though the last two species on the list are 

 Madison forms." 



Though the Nos. 134, 136, 137 and 138, were all collected in the 

 same locality and strata it is barely possible that some might have 

 come from a stratum a trifle lower which might make a considerable 

 difference in age. But I think it will be found that they are all of 

 the same horizon. 



"Old Baldy. Field Nos. 136, 137, 138. 

 Ccelenterata. 



Zap h rent is sp. 



