REVIEWS 765 
Part Il of the report is by Mr. W. R. Crane and deals with the 
detailed stratigraphy as exhibited at the mines, the geographic location 
of the coal fields, the chemical and physical properties of the coal, 
mining methods and mining machinery, statistics of coal companies 
and coal mining laws. It contains the best exposition of the phenom- 
ena of “horsebacks” in the coal that has yet been published. The 
subject is fully illustrated by clear-cut drawings. Mr. Crane thinks 
the “horsebacks” are the result of fissures produced by vibratory 
movements of the strata, the fissures thus produced being filled with 
clay, either by the removal of pressure or by “ creeping,” these vibratory 
movements, he thinks, in all probability accompanied the Ozark uplift. 
Rolls and “bells” and other stratigraphical phenomena are explained. 
According to the author there are 15,000 square miles of productive 
coal fields in Kansas but only a small proportion of this area is being 
worked at the present time. The mines most extensively worked are 
located in the southeastern part of the state. Across the coal area the 
percentage of fixed carbon in the coal and the value of the coal (sel- 
ling price) increases from northwest to southeast. Coal is mined by 
stripping, drifting, pitting and shafting. In the shafts mining is car- 
ried on by means of ‘the long wall system” or “the room and pillar 
system.” 
To the author’s exposition of the chemical and physical properties 
of the coals the greatest importance is attached. He performed the 
work in a very elaborate manner, the tests being made in many differ- 
ent ways, all the results of which are finally placed in a general sum- 
mary. The illustrations of machinery, etc., used in the article are 
from the pen of the author and attest his ability as a draughtsman. 
WieaNee: 
Lwenty-second Annual Report Indiana Geological Survey. W. S. 
BATCHLEY, State Geologist, Indianapolis, 1898. 
The Twenty-second Annual Report of the state geologist gives a 
detailed statement of the work of the department of geology and natu- 
ral resources, for the year 1897. Among the subjects treated in the 
volume is a paper on the ‘Geological Scale of Indiana,” by W. S. 
Batchley and Geo. H. Ashley. This paper shows the geological for- 
mations of Indiana in vertical section, and gives the time, character of 
the rocks, and subdivisions of each group. 
