8 The American Geologitst. Juiy. i89i 
superior «iuality of coal have been discovered and partially devel- 
oped on the western slope of the Colorado range. There are now 
twenty companies at work where before there were but one or two, 
and these not merely on the old fields, but on the new. From a 
once local trade we have now come to supply man}- neighboring 
States as far east as the Missouri river. From nothing as a coal 
State, Colorado has leaped into the front ranks. 
EASTERN COAL AND THAT OF COLORADO COMPARED. 
It has been by no means easy to convince eastern men either of 
the ([uality of Colorado coal, or of the area of its fields as com- 
pared with similar data of eastern states. They have long thought 
of our coals as "lignites," little better than peat, owing to the 
fact that they were so dubbed by Havden in his report of 1873. 
This was true enough of the northern field about Boulder, but 
wholl}- unjust to the great bulk of our coal fields, which produce 
true bituminous coal — the same in quality and character as that of 
Pennsylvania. We have coals that not only produce good coke, 
equal, some of it to that of Connellsville, but even anthracite, 
limited in quantity, similar to that of the eastern states. This 
fact is emphasized b}' the leading coal expert and geologist of the 
eastern states. Dr. J. S. Newberr}-, of the Columbia School of 
Klines of New York, who says of our Colorado fields west of the 
range : 
' ' Here we see sometimes eight to ten difterent seams in one 
section, reaching a united thickness of fort}' to fifty feet, of a 
quality which will compare with any known in the v.xnld. Owing 
to peculiar conditions this coal forms several varieties, each of 
which has its special uses. Here is anthracite, as hard and bright 
as any mined in eastern Pennsylvania ; semi-bituminous coals, 
similar to those of Blossburg and Cresson, but more compact and 
pleasanter to work, transport and use; liituminous coal, yielding 
a coke as good as that of Connellsville, and open-l)urning furnace 
coals similar to the famous Briar Hill coal, of Ohio, and of e(iual 
value. These coals are of unusual purity, sometimes containing 
3 per cent, and rarely more tlian 5 per cent, of ash, with little sul- 
phur or pliosphorus. "' 
Our fields belong geologically to the Cretaceous, but what old 
age and pressure have done for the eastern coals, has ])een accom- 
plished for ours by the heat of volcanic eruptions attendant upon 
mountain upheaval. 
