Title: Annual report. 1st-12th, 1867-1878
Identifier: annualreport1st106geol (find matches)
Year: 1867 (1860s)
Authors: Geological and Geographical Survey of the Territories (U. S. ); United States. General Land Office; United States. Dept. of the Interior
Subjects: Geology
Publisher: Washington, Govt. Print. Off.
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Smithsonian Libraries

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GEOLOGICAL SURVEY OF THE TERRITORIES. 71 syncliunl the beds are mucli crushed, so that very obscure. Ou the opposite side we pass edges of the same series, comuieuc- iiig with the Coal strata, but with a reversed dip. The complete series has been tilted beyoud a vertical, so that some of the high ridges of lime- Stone incline 45°. (Figs. 20 and 2L) Xea'r the upper portion of the Jurassic group there is a bed of gray limestone six feet thi^k, made u[) of an aggregate of small Gasteropod- ous shells. Tills bed is well exposed in both divisions of the synclinal. Patches of the lake-deposits are thinly scattered over the surface, filling up the irregularities, occasion- ally showing a moderate thickness either of marls or conglomerates. As we pass up the Gallatin Valley from its mouth we observe that the river flows along a high-bluff wall on the east side. There are several local synclinals as well as anticliuals, but none of the Carboniferous beds seem to have been affected. In the low hills east of the river, about five miles above the mouth, is a sort of local depression, in which are remnants of the Jurassic gronp. As I have so often repeated in this report and ^ in my previous reports, the evidence is continually shown that the forma- tions all originally extended over the country in a horizontal position at one period; that they have since been removed to a great extent bv erosion, but here and there we find indications of tbeir former existence. The section will show a most exten- sive series of Carboniferous lime- stones rising gradually as we ascend the Gallatin. I described these beds somewhat in detail in my report for 1871. The series of Carboniferous limestones is remarkably well shown for a distance of about five miles above the mouth of the Gal- latin. Just opposite the grist-mill the very compact, brittle beds, which are supposed to be of Silurian age, come in, forming massive bluff-ex- posures. Ju8t beneath these nmss- ive beds of limestone is a series of loose, bi'owu shales and clays with thin layers of impure limestone. they over are the rendered ujiturned
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to O layers lime

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