310 EXPLORATIONS ACROSS THE GREAT BASIN OF UTAH. 



of this ocean in the far West and Southwest during the coal-period amount to almost a 

 proof that the conditions of that area, which now constitutes a part of this continent, 

 were never such as to admit of the production of coal-plants, and the deposition of such 

 materials as make up the Coal-Measures, at least during the latter part of the Coal- 

 Period. In regard to the earlier part of that period, or the time in which the Lower 

 Coal-Measures were formed, we have not at present the means of fully deciding what 

 were the conditions of the central or southwestern part of the continent" 



On the other hand, no decidedly Lower Carboniferous strata have ever been found 

 in those regions before, and we have, therefore, been unable to speak with certainty 

 about the non-existence of stone-coal in the western Coal-Measures, the lower portion 

 of which, the equivalent of the coal-bearing rocks of the Mississippi Valley, might 

 have escaped observation in the far West. Not far from the locality of the shales, I 

 have found Lower Carboniferous strata, and the supposition is obvious that these shales 

 might hold an intermediate position as lower members of the Upper Carboniferous or 

 < 'on 1- Measure series. I have not been able to obtain a section, nor to trace the Upper 

 and Lower Carboniferous strata to their line of connection, and, therefore, cannot ex- 

 press a definite opinion in this respect. The shales certainly hold a position not very 

 high in the series, but I doubt whether they correspond to any particular horizon in 

 the Upper Carboniferous rocks of the East. 



The upper division of the rocks on Timpanogos River, consisting mostly of light- 

 colored sandstones, some siliceous limestones, and a few red, shaly strata, is character- 

 ized by some fossils, which Mr. Meek finds analogous to Permian forms. The differ- 

 ence of their lithological character from that of the Upper Carboniferious rocks lower 

 down in the canon, favors the supposition that they are distinct from them and actually 

 of Permian age, but the evidence is not conclusive. 



^ Our collection contains fossils which point decidedly to the Lower Carboniferous 

 period as the age of a series of rocks in the immediate vicinity of Camp Floyd, west 

 of Lake Utah. These rocks are also dark-colored, impure limestones, slates, and'sand- 

 stones. Part of them are much like some of the rocks in the Timpanogos Caiion 

 while others are much more siliceous, and the fossils are also converted into silex and 

 badly preserved. Among them occurs the spiral axis of an Archimedes, a decidedly 

 Lower Carboniferous type, and the first specimen of this fossil yet found in the region 

 ot the Rocky Mountains. At many other points strata have been observed, to which 



^ Further west, between longitude 115° and 115° 30', andlatitude 40° 10' and 39° 

 20 , there is a series of hills and mountains, trending nearly north and south, also made 

 up of rocks of the Carboniferous age, but of a very different lithological appearance 

 They are several hundred feet in thickness; mostly light-yellowish, more or less are- 

 naceous and argillaceous limestones, with an earthy fracture, also light gray subcrys- 

 talhne, siliceous limestones, and a great deal of light-yellowish, arenaceous and calca- 

 reous slates. 



The limestones are highly fossiliferous, and the greatest portion of them undoubt- 

 edly Upper Carboniferous; but other strata from the outskirts of tin's formation not 

 however, much differing in appearance, are considered bv Mr. Meek as perhaps Lower 

 Carboniferous. Distinct limits could not be drawn. 



