4 PALEONTOLOGY. 



museum of the Smithsonian Institution. In doing this, however, he has 

 been duly credited as the discoverer of each species, and the original types 

 have generally been figured, even where specimens of the same forms are 

 contained in Mr. King's collections ; though figures of the latter have also 

 been given, where better specimens than those first found have been obtained. 



The fossils here reported on, evidently came from the following geolog- 

 ical formations, viz., Lower Silurian, Devonian, Carboniferous, Trias'sic, 

 Jurassic, Cretaceous, and Tertiary. The small number of Lower Silurian 

 forms are represented on the upper part of plate 1. Two of the Trilobites, 

 from Antelope Springs, House Mountains, belong, one to the genus Cono- 

 coryplie, and the other to the genus Paradoxides, or some allied group. They 

 are decidedly Primordial types, and show that rocks belonging to this ancient 

 period occur at that locality.* 



The other Silurian forms merely consist of small univalve shells that 

 came from a gray, granular limestone on the summit of Ute Peak, Wa- 

 satch Eange, Utah. One of these is a small Opliileta, scarcely distinguisha- 

 ble from 0. complanata of Vanuxem, first described from the Calciferous sand- 

 rock of New York. The other two are lenticular, or much depressed forms, 

 with an angular periphery and a large umbilicus, and evidently belong to 

 the same formation, being nearly allied to forms found in beds of the age of 

 the Calciferous period, in Minnesota, Wisconsin, and Texas. From the 

 affinities of these fossils, we can therefore scarcely entertain any doubts that 

 the rock from which they were obtained belongs to the Calciferous epoch. 



The Devonian forms in these collections are more numerous than the 

 Silurian. They are illustrated on the lower part of plate 1, and on plate 2, 

 and the upper part of plate 3. Those on plate 1, with the exception of a 

 small Proetus, to be mentioned further on, came from a light-colored argil- 

 laceous limestone about three miles south of Piiion Pass, Piiion Range, Ne- 

 vada, and consist of a small subglobose, undetermined species of Favosites, 

 Atrypa reticularis, a new Spirifer, a bivalve of doubtful genus, and fragments 

 of a Balmanites. It is possible that the last-mentioned fossil may be an 

 Upper Silurian species, as Mr. King found it in the lowest bed exposed at 

 the locality, and it seems to be quite as nearly allied (so far as its charac- 

 * See Proceed. Acad. Nat. Sci. Philad., Ap. 1870, p. 5G. " 



