DEVONIAN FOSSILS. 481 



From the base of the bluff on Little Sunlight Creek only Atrypa reticu- 

 laris is known, a small coarsely plicate variety. It is similar to, perhaps 

 identical with, the type figured by Walcott (Mon. U. S. Geol. Survey, Vol. 

 VIII, 1884, PL XIV, figs. 6, Qa, Gb), and mentioned as occurring in the 

 upper part of the formation (p. 150). Meek cites the same form (King's 

 Rept. U. S. Geol. ExpL 40th Par., Vol. IV, 1877, p. 39) from Pinon Station, 

 Treasure Hill, White Pine district, etc., and figures it on PL III, figs.' 6, 6a. 

 The horizons of Bighorn Pass, Gallatin Range, near the divide between 

 Gallatin Valley and Panther Creek; the east slope of Antler Peak, Galla- 

 tin Range; and the south slope of the same, can be correlated with one 

 another and constitute a separate group. The matrix is" a calcareous sand- 

 stone; and the included fossils, almost exclusively corals, are crudely silici- 

 fied. The common fossils are Cladopora sp., Pachyphyllum sp., Cyathophyllum 

 ccespitosum (?), and Actinostroma sp. Every indication points to the Devonian, 

 age of this bed. The genus Actinostroma is characteristic of, though not 

 restricted to, Devonian rocks. Cyathophyllum ccespitosum, as identified in 

 this country, occurs in Upper Helderberg strata. The genus Pachyphyllum 

 is characteristically Devonian, and Cladopora sp. is more closely related to 

 certain Upper Helderberg forms than to any I have found described. 



The material from the south side of Soda Butte Creek, northeast of 

 Abiathar Peak, Absaroka Range, from northwest of Abiathar Peak, Soda 

 Butte Canyon, and from the north side of saddle west of Mount Miller, 

 Absaroka Range, represents, perhaps, the same horizon as that from The 

 Gate, Fossil Hill, and Eureka district, whose fauna, as described by Meek 

 and by Walcott (loc. cit), is quite similar, as far as it goes. In the Yellow- 

 stone Park this consists of Atrypa missouriensis, Spirifer engelmanni, Athyris 

 vittata var. triplicata n. var., Pleurotomaria (?) sp., Pachyphyllum sp., Cyatho- 

 phyllum caspitosum (?), etc. Atrypa missouriensis is, I believe, the same form 

 figured by Walcott as A. desquamata Sow. (loc. cit. PL XIV, figs. 4, 4a), and 

 by Meek as A. reticularis var. As in their collections A. missouriensis was 

 associated with the small, coarsely plicate Atrypa, which I have found alone 

 at Little Sunlight Creek, it might perhaps be better to regard the latter as 

 forming one of the group of localities under consideration. This group, on 

 the other hand, is connected with the other previously mentioned (Bighorn 

 Pass and Antler Peak) by having in common Cyathopliyllum ccespitosum 

 (doubtful identification) and Atrypa missouriensis. A bed at the south side 



MON XXXII, PT II 31 



