556 GEOLOGY OF THE YELLOWSTONE NATIONAL PARK. 



Spirifer hirtus, from the same beds and the same region as R. cooper- 

 ensis, may almost certainly be placed in the synonymy of the latter species. 



Formation and locality: Madison limestone, east side of Gallatin 

 River, west of Electric Peak; Upper Gallatin Valley, west of Bighorn 

 Pass; Arnold Hague. Amphitheater west of Bannock Peak, Gallatin 

 Range, bed 26; W. H. Weed. Crowfoot Ridge, Gallatin Range, top of 

 bed 25; J. P. Iddings and G. M. Wright. Same, top of bed 26, top of bed 

 27, bed 28, bed 31; J. P. Iddings and W. H. Weed. South of Forellen 

 Peak, Teton Range; S. L. Penfield. South slope of peak west of Antler 

 Peak, Gallatin Range; J. P. Iddings. North of Bighorn Pass, Gallatin 

 Range; A. C. Gill. Head of Conant Creek, Teton Range; W. H. Weed. 

 Chouteau age, Chouteau Springs, Missouri; Rockford, Indiana; Burling- 

 ton, Iowa; Hickman County, Tennessee; Richtield, Bagdad, etc., Ohio. 



Reticularia cooperensis var. 



PI. LXX, figs. 6«, 6b, 6c. 



iSpirifera, setigera Hall and Whitfield, 1877 : King's U. S. Geol. Expl. 40tk Par., Vol. 

 IV, p. 270, PI. V, tigs. 17, 18. 



This form is once again as large as R. cooperensis, of which, for the 

 present, I regard it as a variety, but I am not in a position to designate 

 any other character on which a differentiation can be made. The single 

 specimen found in the collection stands out so strikingly from the material 

 referred to R. cooperensis that it is significant of further difference, but the 

 specimen is so exfoliated and crashed that a detailed comparison, which 

 might bring out constant important contrasts in surface ornamentation, etc., 

 is impossible. 



As far as the limited material permits me to judge, the same form 

 occurs in the Eureka district and at Dry Canyon, Utah, where it has 

 uniformly been identified as R. setigera Hall, of the Chester limestone, 

 which it strongly resembles. However, in the Yellowstone National Park 

 it is in the lower part of the Carboniferous series, associated with Waverly 

 forms (R. cooperensis, etc.). 



A comparison with specimens of R. setigera from Chester, Illinois, 

 shows that the Waverly form is of about the same size, but more transverse, 

 beak less incurved, area higher and larger. As has been said, a comparison 

 of the surface ornamentation of the two forms is not possible. 



