1 82 The American Geologist. March, 1900 
Indiana, Department of Geology and Natural Resources ; Twenty- 
t/ii>-d Annual Repo?'t, i8q8. W. S. Batchley, State Geologist, India- 
napolis, 1899. Pages xxvii, 1741; with 93 plates and 986 figures in the text. 
This large volume, prepared mainly by Dr. George H. Ashley, in 
charge of the coal survey of the state, embodies the principal work of 
the three years 1896 to 1898, inclusive, with shorter reports of the 
state inspector of mines, the natural gas supervisor, and the super- 
visor of oil inspection. For the coal fields of Indiana, which comprise 
about 7,000 square miles in its southwestern part, extending into Ill- 
inois, this volume is very thorough and detailed. 
The discovery of natural gas in Indiana in 1886, and its ensuing great 
development for manufacturing, decreased the demand for coal, se- 
riously crippling the coal-mining industry; but it is now seen that 
the supply of natural gas is rapidly diminishing and will be practically 
exhausted in the near future. The large resources of coal in Indiana 
are therefore receiving renewed attention and utilization, which will 
be stimulated and aided by the information here published. During 
1898, the seventeen coal-mining counties produced 5,177,044 tons of 
coal, employing 9,325 miners. 
The Indiana production of petroleum for the same year is stated as 
^^75^^307 barrels being about 15 per cent, less than in 1897, but having 
about 25 per cent, greater value, the respective values for 1897 and 
1898 being $1,871,849 and $2,325,810. w. u. 
A General Report on the Physiography of Maryland. A Dissertation 
presented to the President and Faculty of the Johns Hopkins University 
for the Degree of Doctor of Philosophy. By Cleveland Abbe, Jr. 
This volume is an excellent summary of the history of a region 
which may be regarded as typical of the unglaciated portion of the 
eastern United States. In it are represented the three great topo- 
graphic regions of the Atlantic states, — Coastal Plain, Piedmont 
Plateau and Appalachian Region. The occurrence of each in Mary- 
land is representative of the entire division. 
Dr. Abbe begins his work by a discussion of general physio- 
graphic principles, illustrating them by many examples taken from 
Maryland. He describes processes of denudation, of construction, and 
of drainage derelopment. In his discussion of cycles of erosion, he 
follows Tarr in doubting the frequent occurrence of absolute base- 
levelling. Having thus brieflj-^ reviewed the processes which control 
the physiographic development of any area, he takes up in detail the 
history of Maryland. 
The detailed portion of the work embraces a statement of the 
boundaries and topographic features of each province; a discussion of 
its structure and drainage; and an account of its history and economic 
characteristics. It closes with a report of Dr. Abbe's own investiga- 
tions in regard to the history of the Piedmont streams. 
The Coastal Plain is ordinarily regarded as consisting of that por- 
tion of land which lies between the Atlantic ocean and the fall line. 
