Review of Recent Geological Literature. 819 
stone industries the dift'erent kinds of stone noted are granite, marble, 
slate, sandstone, liniestone and bluestone. Granite includes all quar- 
ried igneous rocks, gneisses and crystalline schists. The total produc- 
tion of stone in the United States for 1894 was valued at over $37,000,000 
— a gain of about $3,500,000 over the total production for the previous 
year. A large number of statistical tables accompany the paper, and 
some information is given concerning the methods of quarrying and 
dressing the various stones. A locally interesting feature is a brief de- 
scription of the status of each kind of stone industry in each state. 
u. s. G. 
Mineral Products of the United States, calendar years 1885 to 1894. 
By David T. Day, Chief of Division of Mineral Resources. (U. S. Geol. 
Survey: Washington, June 8, 1895.) On a large sheet, about 24 by 30 
inches, is presented a tabulated statement of the quantity and value of 
each mineral substance produced in the United States during the last 
ten years. The value of the total product decreased decidedly both in 
1893 and 1894. The total valuation in the latter year was $527,655,562, 
which is lower than the total valuation of any year since 1887. The 
greatest total production was in '92 when the valuation was $648,616,954. 
u. s. G. 
Opinions Concerning the Age of the Sioux Quartziie. [Abstract.] By 
Charles Rollin Keyes. (Proc. Iowa Acad. Sci., 1894, vol. 2, pp. 218- 
222; 1895.) A resume is given of the opinions of various authors re- 
garding this quartzite which was called "Sioux quartzite" first in 1870 
by Dr. C. A. White. It is of interest to note that Dr. F. V. Hayden 
seemed inclined to the view that the age of this rock was post-Carbon- 
iferous and perhaps Cretaceous. The general consensus of recent opin- 
ion regarding this quartzite is that it is of pre-Cambrian age; it is 
placed in the middle division (Upper Huronion) of the Algonkian in re- 
cent publications of the United States Geological Survey. Prof. N. H. 
Winchell has been about the only one lately to entertain a different 
opinion and he has in several papers uniformly placed it in the Cam- 
brian. In the present paper the author states that the fossils (a brach- 
iopod and a trilobite) found in the Sioux quartzite are generally re- 
garded as not oi organic origin. The reviewer does not understand that 
this is the case with the brachiopod (Lingula calumet,) which seems to 
be generally acknowledged as a fossil. He understands that both 
Messrs. Walcott and Van Hise are agreed as to its organic origin; the 
latter writes: "In the Sioux quartzites one generally accepted fossil has 
been found by N. H. Winchell." (Bull. 86, U. S. Geol. Survey, p. 194.) 
Dr. Keyes entertains some doubt as to the pre-Cambrian age of this 
quartzite. In his closing paragraph, after a personal examination of 
many of the principal outcrops, he states "that it must be confessed 
that notwithstanding strong preconceived notions regarding the great 
antiquity of the Sioux rock, faith in its very old age was considerably 
shaken ***** Regarding the age of the Sioux formation, it may 
be said that while it should be considered as pre-Cambrian in age - 
