292 EXPLORATIONS ACROSS THE GREAT BASIN OF UTAH. 



of their existence at any horizon ; and our knowledge of their fossil fauna is so very 

 limited and so full of startling possibilities, that I am inclined to regard these paleon- 

 tological deductions as less reliable, especially where few and new species are con- 

 cerned, because the precedents are few. 



I have noticed the formation only at a single locality. In Colonel Fremonts' 

 report, however, Professor Hall describes a fossil from Uintah River, near latitude 41°, 

 longitude 111 as ( 'crith'nim taienwt, which is bv Mr. Meek considered as identical 

 with a Mrhnna from these estuarv beds, and a Turbo and Xatica (?) from a point on 

 Muddy Creek, below the crossing of the Salt Lake City road, apparently identical 

 with /WW///,/* from Bern- River, while the description of the lithological character of 

 some Of the strata of these localities rather corresponds to No. 2 of the Fort Bridger 



Besides the two formations which have just been described, we have observed 

 some local deposits overlying, unconformably, the older rocks, which, on that account, 

 we provisionally refer to the Tertiary period. On Porter's Creek, the main southern 

 fork of White Clay Creek, and less prominent on the latter stream, we find siliceous 

 conglomerates apparently filling depressions in strata which are probably of Cretaceous 

 age. They are composed of hard sand roek and pebbles of quartz, all rounded, vary- 

 ing in size gem-rally between a hen's <^ and a man's head, and imbedded in little 

 sandy matrix, which, although easily yielding to main force, well resists destruction 

 by atmospheric agencies. These conglomerate-, therefore, form remarkable turreted 



They must not be confounded with the conglomerates interstratmed in that older 

 series of rocks, which have a similar appearance, but generally a more calcareous 

 matrix. Occasionally they include more sandy portions irregularly interspersed, and 

 on White Clay Creek I noticed them underlaid by a few strata of sandstone and shale, 

 both together capping, unconformably, the older sandstones. No fossils have been 

 found in connection with them. 



Covering the Tertiary formation, I noticed frequently, especially on the edge of 

 high ridges, bowlders of siliceous rocks, highly-altered sandstones, and the like, some 

 ol which contained traces of fossils which appear to be Carboniferous forms. They 

 probably originate from the high mountains in the western part of the Wahsatch 

 range. 



CRETACEOUS, JURASSIC, AND TRLA.SSIC FORMATIONS. 



I have already mentioned the possibility of the Upper Cretaceous age of No. 3 of 

 the Fort Bridger series, and the probably Cretaceous age of the formation on Bear 

 River. Along our route no strata are exposed which lithologieallv correspond to the 

 Nos.II and III of the Cretaceous rocks of Nebraska: but further south, at Bryan's Pass, 

 I had previously observed them on the dividing ridge, beyond which they probably 

 extend westward into the Green River country, together with the Cretaceous Lignite 

 formation overlying them in that vicinity, and to" which the coal strata appear to 



lower down on Green River the Cretaceous formation appears to be lar-elv developed 

 In the eastern part of the Wahsatch Mountains the Cpper Cretace.'ais beds are 



