644 REVIEWS 
sandstones by interstitial growth. He favors the view that the quartz- 
ites are of early age, the probable equivalents of the Mankato and 
Baraboo quartzites. 
Professor Norton introduces his discussion by a statement of the 
theory of artesian wells and their requisite conditions. He then describes 
the conditions of the lowa field, discussing the geological struct- 
ure, the area of supply, the reservoir and the conditions of transmission. 
This is followed by a description of the wells classified by sections. 
Under the head of chemistry of the waters he treats of the mineral 
ingredients, of the interpretation of analyses, and of the classification 
based on these; and also of the therapeutic, sanitary, and industrial 
qualities of the waters. He also touches upon the questions of public 
supply, of cost, of purity and of practical matters relative to drilling, 
thus giving to the report much popular as well as scientific interest. 
The paper of Mr. Bain embraces a special study of the relations of 
the two drift sheets found in the vicinity of the capital. After a 
careful statement of the history of investigations, he describes, critically, 
the Des Moines lobe of the Wisconsin drift as it appears in Pope, Dal- 
las, and Guthrie counties, and follows this by a similar critical discus- 
sion of the characteristics of the older drift which underlies it, and 
occupies the region lying to the south. An important feature of the 
paper is the discussion of time ratios as indicated by erosive and other 
phenomena. From the computation of special cases selected as being 
best suited to the purpose, he reaches the conclusion that the time 
ratio between the Wisconsin and the Kansan ranges from 1:10 to 1:15, 
being probably nearer the latter than the former. ee 
The Iowa survey is to be congratulated upon the excellence of this 
report. ibs G. 
Geology and Natural Resources of Indiana, Twenty-first Annual 
Report. By W. S. BiaTcHLey, State Geologist. Indian- 
apolis, 1897. 
This report of 718 pages embraces ‘‘An Introduction” and ‘The 
Natural Resources of Indiana,” by W. S. Blatchley ; ‘‘The Petroleum 
Industry in Indiana,” by the same; ‘The Composition of Indiana 
Coals,” by W. A. Noyes; ‘“‘Some Notes on the Black Slate or Genessee 
Shale of New Albany,” by Hans Duden; “The Indiana Caves and their 
Fauna,” by W. S. Blatchley ; ‘“A Report on the Geology of the Middle 
