141 



[Cope. 



remark from Dr. Ilayden, relative to the sediment of the apper basin, 

 " that they remind on^ of the Jura Trias red beds." Tliis remarlc is forci- 

 bly illustrated by the character of the sediment found in the south-western 

 part of the basin, near the head of Gooseberry creek, where the exposures 

 consist largely of thick strata of the red clay, which gradually thin out to 

 the north and east, blending with the pink, blue, and buff colors. In the 

 northern part of the basin, and along Stinking river, the sediment consists 

 almost exclusively of a pale yellow sandstone of a bluish tinge, from which 

 few fossils were obtained. 



The clays contain much lime in the form of small limestone nodules of 

 a rusty brown appearance, in which the fossils are often found, having a 

 thin and intensely hard layer of ferrous oxide investing them externally. 

 In the red the fossils are always scarce and fragmentary, and when found 

 are usually such parts as would, under the most favorable circumstances, 

 be preserved. The blue seems to be the more productive, and to have 

 offered better conditions for their preservation ; but, owing to the fact that 

 lime forms the petrifying base, and being less able to withstand the heavy 

 pressure than many other materials, the fossils from both the red and the 

 blue are, as a general rule, greatly distorted and crushed. This fragmen- 

 tary occurrence of fossils in the fine-grained clay, I am inclined to believe, 

 is due, not to a scattering of the bones by currents, but rather to imperfect 

 and unfavorable conditions for their preservation. That entire skulls and 

 skeletons were deposited, where now nothing but the teeth remain, I am 

 well satisfied from the circumstance that both superior and inferior series 

 are not unfrequently found in proper position without a trace of ramus or 

 cranium. In the sandstones, however, the fossils are in a magnificent 

 state of preservation, but their extreme scarcity in this material gives the 

 collector many long and fruitless searches. Two skeletons which have 

 proven of considerable interest were all of any consequence that were 

 obtained from the sandstones. 



The general stratigraphical appearance, as well as the scattered and 

 fragmentary condition of the fossils, together with the community of a 

 large number of genera, refer it to the Wasatch epoch, but a full discus- 

 sion of this point belongs properly to the paleontologist. A thorough 

 elucidation will be found in Prof. Cope's paper on the fossils. 



The exploration of this region is most arduous and diflicult. The great 

 scarcity of water in these bad land wastes, makes it very inconvenient, 

 and renders it necessary to carry a water supply a distance of often 20 

 miles or more. Even when Avater does exist it is so strong Avith alkali as 

 to be scarcely fit for use. Many of the streams coming down from the 

 mountains dry up as soon as the snow has melted from the low 

 foot hills in early spring, leaving large tracts entirely destitute of water, 

 which frequently abound in fossiliferous exposures, and which it is the 

 object of the explorer to examine. The broken and mountainous chai'ac- 

 ter of the country forbids the use of wagons to such an extent that pack 

 animals are indispensable. 



