128 PROCEEDINGS OF THE ACADEMY OF 



Devonian localities alluded to above, interrupted at places by outbursts of ig- 

 neous rocks. It is likewise probable there may be in this interval both Devo- 

 nian and Silurian strata, but the collections yet obtained are not sufficient to 

 enable us to speak with confidence on this point. 



Between Long. 115 and 115 30', Lat. 40 10' and Lat. 39 20', there is a se- 

 ries of hills or mountains, trending nearly north and south, to unknown distances 

 beyond the field of these explorations, which seem to be mainly made up of 

 lio-ht yellowish gray, more or less argillaceous, and arenaceous subcrystalline 

 limestones, and slates. This formation belongs to the Carboniferous system, 

 but is more recent than the dark colored limestone at Camp Floyd. The 

 fossils collected from it are for the most part new, and consist of three species 

 of Productus, one of which resembles P. Rogersi, Norwood and Pratten, two 

 new species of Spirifer, and another apparently identical with S. cameratus, but 

 more robust, and having stronger costae than is common in that species. Along 

 with these there are also specimens of Athyris sublilita, and a new species of 

 Chonetes, closely allied to C. Verneuiliana, Norwood and Pratten, from the Western 

 Coal Measures. From the affinities of this group of fossils, we have little hesita- 

 tion in referring this rock to the Upper Carboniferous series, though in its 

 lithological characters it is entirely unlike strata of that age in the Middle and 

 Western States. 



There were also seen at a few places near here, some outcrops of dark grayish 

 colored limestones, containing Productus, Spirifer, &c. These were not ob- 

 served in contact with the light colored beds mentioned above, but under 

 circumstances indicating that they hold a lower position, from which it is 

 inferred they are probably of lower carboniferous age. 



The occurrence here, as far west as Long. 115, of extensive Carboniferous 

 formations, is another interesting fact in the geology of this distant region not 

 known previous to these explorations, no rocks of this age being represented 

 on any of the most recent and carefully compiled geological maps, from near 

 Camp Floyd and the Salt Lake to the Pacific Ocean. 



Deposits, probably of the age of the Coal Measures and of great thickness, 

 were also observed in the Wahsatch Mountains east of Lake Utah, along Tim- 

 panogns Canon. The strata here, however, consist mainly of dark colored and 

 bluish impure limestones, slates, and argillaceous shales, the latter containing 

 at a few places fragments of carbonaceous matter, the whole being upheaved 

 and greatly distorted, apparently by violent forces acting from beneath. The 

 fossils collected from these beds all differ specifically from those found in the 

 light colored limestone at the localities near Long. 115 west, and we have no 

 means of determining which of these is the older rock. The specimens from 

 the dark colored beds in the Caiion, consist of one new or undetermined Spirifer, 

 two of Productus, and two of Athyris, together with fragments of a small 

 Lepidodendron. 



The indications of Coal of true Carboniferous date, seem to be more favorable 

 here than at any other point examined along the route explored, though no beds 

 of it were seen. Good coal has, however, been found in the same mountain 

 range 140 miles south of this, but as yet little is positively known in regard to 

 its age. 



Several miles above this on Timpanogos River, and at a higher geological 

 horizoD, outcrops of light colored, and yellowish sandstones and silicious lime- 

 stones, with red shales, were seen. At one place in this formation a few speci- 

 mens of very hard, light gray, highly silicious rock were obtained, containing 

 great numbers of small bivalves, in a broken condition. As, near as could be 

 determined these are very much like Bakevellias, while another of these speci- 

 mens contains a fragment resembling closely a Phyllipora. Both these fossils 

 are quite similar to Permian forms, but it would be unsafe without other evi- 

 dence to refer the rock to that epoch. 



[April, 



