14 The American Geologist. juiy. i89i 
to Green river aud beyond, the coal probabl}- underlying a large 
tract of country east of the AVahsatch mountains. 
Along the opposite margin coal is traceable west from Ci'ested 
Butte, along the anthracite range and the south base of the Ragged 
mountains, down Crystal river to Coal Basin. Along the anthra- 
cite range and flanks of the Ragged mountains are local patches 
of very fine anthracite, but somewhat Ijroken up, detached and 
difficult of access. 
From New Castle the coal follows the course of the Great Hog- 
back to Meeker, a distance of fort}' miles. Thence it bends in a 
curve in a northerly direction towards Yampa river, and appears 
again on White river, below the mouth of Piceance creek. After 
this it follows the Uintah range into Utah and Grand river. 
In the coal basin at Jerome Park, and at the Marion and Sun- 
shine mines near Cardiff, on the Roaring Fork, which lie around 
such eruptive centers as Mount Sopris and the Elk range, the coal 
is largel}" coking, producing a coke of great purity, at times equal 
to that of Connellsville. Jlills estimates the coking area of this 
district at 353 square miles. 
On the cliff face of the Great Hogback, 1,000 feet above the 
Grand river, we see exposed a great number of seams varying in 
thickness from twenty-two feet near the base, to ten and five feet 
near the summit. The coal along this hogback is first-class bitu- 
minous domestic coal, not coking, but freer from soot than those 
of a coking nature. 
On the field around Meeker, owing to the absence of railroads, 
and the distance from markets, little development has been done. 
The coal appears like that at New Castle. 
WHERE ANTHRACITE IS FOUND. 
This Grand River field produces many good varieties of coal, 
the bulk of it being domestic and not coking. The anthracite 
area, so far as at present known, is in Colorado, confined to nar- 
row areas along the Anthracite range, the flank of the great vol- 
canic mountains, such as mount Marcellina and the Ragged 
mountains, and the small mesa at Crested Butte and the southern 
flanks of mount Gunnison, together with an undefined area in the 
Yampa field. Some of this so-called anthracite is more strictly 
semi-anthracite, excellent coal, but variable in thickness and 
quantity, and liable to have been broken up by the volcanic sheets 
which anthracised the coal. The largest and most promising an- 
