Annual report of the United States Geological Survey to the Secretary of the Interior . ust referred to. a littleto the south of the fortieth parallel, there are layers of red slate a fewfeet in thickness interbedded with a light-gray volcanic tuff, containingnumerous small feldspar phenocrysts which weather white. The tufflayers contrast very noticeably with the red slate. The strike of theseries is 13° west of north and the dip is 00° E. The groundmass ofthe tuff (No. 63 S. N.) shows traces of a flow structure in the arrange-ment of the particles. Whether or not this lava has the composition
Annual report of the United States Geological Survey to the Secretary of the Interior . ust referred to. a littleto the south of the fortieth parallel, there are layers of red slate a fewfeet in thickness interbedded with a light-gray volcanic tuff, containingnumerous small feldspar phenocrysts which weather white. The tufflayers contrast very noticeably with the red slate. The strike of theseries is 13° west of north and the dip is 00° E. The groundmass ofthe tuff (No. 63 S. N.) shows traces of a flow structure in the arrange-ment of the particles. Whether or not this lava has the composition ofa trachyte was not determined. CALAVERAS FORMATION. No evidence of the age of the Calaveras formation has been obtainedbeyond that given in the preceding However. Professor Smith,in his paper on the metamorphie series of Shasta County, finds thatthe McCloud limestone, which is regarded by the writer as part of the ? See also Am. Geologist, Vol Jour, of Geology, Vol. II. |>l>. 599-601. U. S. GEOLOGICAL SURVEY SEVENTEENTH ANNUAL REPORT PART I PL. XXIX. a. NODULE IN QARTZ-MICA-DlORITE, SURROUNDED BY A RIM OF BLACK HORNBLENDE. b. HORNBLENDIC INCLUSION IN HORNBLENDE LABRADORITE-PORPH YRY DIKE. TURNER.] CALAVERAS FORMATION. 029 Calaveras formation, is in part Upper Carboniferous. After giving thelist of fossils determined by Meek from Bass ranch, Professor Smithwrites as follows: Taken by itself the fauna would not lie characteristic of Upper Carboniferous, andindeed it is arbitrary tu draw the line at the base of the limestone. Even Fmulinacylindrica, which in tbe region east of the Rocky Mountains seems to be character-istic of Upper Carboniferous, in Nevada is found also in Lower Carboniferous. Butthe most decisive proof of the Upper Carboniferous age of these strata is their posi-tion so far above the Baird shales, which have been shown in this paper to be equiva-lent to the Lower Carboniferous of the Eureka district, Nevada, which is known tooccur
Size: 1288px × 1940px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., book, bookcentury1800, booksubjectgeology, booksubjectwatersupply
