116 The Aiiiericdii (ieoloijist. AuKU.-t, 1S95. 
clustry was introduced in Germany. \]\i tj 1875 all the Portland cement 
used in this country was imported principally from Germany and Eng- 
land. There are now factories at Bellefountaine, Ohio: South Bend, 
Indiana: Warner's, New York; and Yankton, S. D. In 1889 there were 
only 159,000 barrels of cement manufactured here and 659,000 imported, 
so that there would seem to be abundant room for more factories. 
Prof. Jameson's monograph is the outgrowth of his lectures before 
the engineering students at the State University of Iowa. While the 
subject is Portland cements, the author gives considerable information 
regarding cements and limes of all kinds. It is noteworthy that, whereas 
Gilmore's work, the last preceding general treatise on cements from the 
American standpoint, is so largely taken vip with descriptions of the 
Roman cements and Portlands are only incidentally discussed, in the 
present volume the relations are transposed. 
The work includes studies on the manufacture, testing and use of the 
cement. In connection with the latter are some beautiful illustrations 
of monolithic construction as employed in the dams of the Hennepin 
canal and the museum of Stanford University. The economy with 
which the vast chalk beds of the interior may be vitilized and the ex- 
cellent character of the product is insisted upon. The monograph is 
exceedingly valuable to all working in economic geology, since it places 
in convenient form a vast quantity of matter which was before scattered, 
principally in French and German works, and was well nigh inaccessi- 
ble. In addition much new matter of great value is given. H. F. b. 
Origin and Use of Natural Gcis at Manitou.Cnlorado. By William 
Stkiebly. (Colorado College Studies, Fifth Ann. Pub., jjp. 14-35. 
Colorado Springs, 1894.) In considering the origin of the gas-charged 
mineral water at Manitou the author gives a brief resume of the geo- 
logic features of the region. It is pointed out that the springs are lo- 
cated on the crests of low folds in the sedimentary strata near the con- 
tact of these beds with the Archean granites. Attention is called to 
the presence of a prominent fault at the exact contact and of a series of 
smaller parallel slips. The study of a number of chemical analyses al- 
lows .several interesting inferences to be drawn, among which are the 
following: 
1. All the springs hold the same salts in solution, a fact which seems 
to point to a common origin. 
2. The waters of the Navajo and Manitou springs are almost identical 
in mineral contents, while the Ute Iron spring contains a much smaller 
quantity of dissolved salts. It is very probable that percolating waters 
from the streams or fi-om local seepage channels make their way into 
the springs — such influx being greater in some springs and smaller in 
others. In the Ute Iron spring calcium and magnesium are low, and 
silica, chlorine, iron, sulphuric-anhydride, soda and potash relatively 
high. The proximity of this spring to the silicate rocks on the south, 
and to the very broken siliceous Silurian limestone and Cambrian 
quartzites on the north and west, suggests reasons for a possible change 
