so FIELD MUSEUM OF NATURAL HISTORY 
is arranged according to the more elaborate classification of the 
U. S. Department of Agriculture. 
Hall 69. 
COALS OF THE UNITED STATES. 
Here one may study the distribution and extent of the coal 
fields of the United States, also the kinds of coal produced by 
each and the available means of transportation. 
On a large plate-glass map in the center of the hall, scale ten 
miles to one inch, the coal fields of the United States as devel- 
oped in 1892 are indicated by areas in black, and the principal 
railroads connecting them are also represented. 
In cases adjoining are shown specimens taken from these 
different fields, the exact locality of each being indicated by fig- 
ures on the labels corresponding to those on the map. The order 
of numbers is the same as the alphabetical order of the states. 
The specimen labels show the uses of the coal, the names of the 
operators of the mines, the means of transportation, the markets, 
and the analysis of the specimens. Other data will be given to 
anyone desiring to obtain them, on application to the Curator. 
Hall 70. 
COALS AND HYDROCARBONS. 
This hall contains a series of the carbon minerals, beginning 
with the diamond, and passing through graphite and the coals, 
(anthracite, semi-anthracite, semi-bituminous, bituminous, and 
lignite) to bitumen and asphalt. 
The occurrence of diamonds is illustrated by diamonds in 
the “Blue Ground” or matrix in which they occur at the De 
Beers mines, Kimberley, South Africa. A series of the diamond - 
bearing gravels of Brazil is also shown. 
Graphite is represented by a series of amorphous and crystal- 
line graphites together with the artificial material made in the 
electric furnace. 
Asphaltums form a series of specimens of diverse characters, 
from the hard, glassy uintaite to the soft, semi-liquid malthas. 
With them are placed the oil shales from which kerosene may 
be distilled and the ozocerites or natural paraffins. 
The coals and lignites represented are as follows: 
