64 The Afucrican Geologist. January, i89s 
In these economic and hydrograpliic papers, and in tlie two volumes 
forming Part III, on the resources of our mines and quarries in 1895, 
compiled by many specialists under the supervision of Dr. David T. 
Day, a vast amount of information is presented, descriptive, historical, 
and statistical, which is adapted directly to promote the industries and 
material prosperity of the whole country. 
The first paragraph of Dr. Day's report sums it up very concisely, 
and indicates its close bearing on our business interests, as follows: 
■'The total value of the mineral products of the United States for the 
year 1895 increased nearly one hundred million dollars beyond the 
value of 1894, or from $527,144,381 to $622,687,668. This increase is a 
long step toward recovery from the depression to which the mineral 
industry, like all others, has been subjected. The total value is slightly 
less than the greatest we have ever known, which was over $648;ooo,ooo, 
in 1892. In terms of quantities produced, instead of value received. 
1895 is greatest. In other words, prices are lower." 
Papers on iron ores, by John Birkinbine, and on the iron and steel 
industries, by James M. Swank, occupy 49 pages; statistics of gold and 
silver production, 8 pages; and a paper on copper production, mainly 
statistical, by Charles Kirchhoff, 49 pages; while lead, zinc, quicksilver, 
manganese, tin, aluminum, nickel and cobalt, chromic iron, antimony, 
and platinum, are similarly noticed, with tables of their recent yearly 
production. The paper on coal, by Edward W. Parker, fills 258 pages. 
Coke (78 pages), petroleum (iii pages), and natural gas (18 pages), are 
treated by Joseph D. Weeks; asphaltum (8 pages), by Mr. Parker; stone 
(53 pages), by William C. Day; clay (64 pages), by Jefferson Middle- 
ton; cement (13 pages), by Spencer B. Newberry; and precious stones 
{2,2 pages), by George F. Kunz; besides other papers, with statistics, on 
flourspar and cryolite, mica, asbestos, graphite, mineral paints, barytes, 
abrasive materials, phosphate rock, sulphur and pyrites, gypsum, salt, 
and mineral waters. w. u. 
Iowa. Geological Survey, Vol. 6, Attnual Report, i8g6, with ac- 
companying papers. Samuel Calvin, State Geologist. (555 pp., 1 1 
pis., II maps; Des Moines, 1897.) 
From the fifth annual report of the state geologist, which is included 
in this volume, the following facts concerning the work of the Iowa 
survey are taken: During 1896 six counties were surveyed and during 
previous years fourteen counties. In twelve other counties the field 
work is partly or wholly done, making a total of thirty-two counties in 
which detailed areal investigations have been conducted. At the same 
time certain features of other counties have been studied in connection 
with reports on special subjects, as the report on coal deposits or that 
on artesian wells. In the areal county work those counties have been 
selected first which contain deposits of great economic importance or 
which offer a means of solution of a large number of geological prob- 
lems. During the last year special attention has been given to the 
study of the Devonian, the Coal Measures and the Pleistocene, and in 
