HATOEN.j GEOLOGY— LIGNITIC GROUP SECTIONS. 33 



appear in the form of uplifted ridges. This belt, though varying much 

 in width, is not again interrupted until we reach a point within a few 

 miles of the Union Pacific Railroad, west of Cheyenne. Sometimes this 

 belt extends out from the mountain foot-hills four or five miles, and 

 again it closes up so that the Lignitic bed, as at Golden City, extends 

 up to within one-fourth or one-half a mile of the granites. 



I need not describe again the geological features of the district about 

 Golden City, so much has already been written, nor need I repeat; the 

 fifty or sixty species of fossil plants which have already been detected 

 in this far-famed locality. On the map which accompanies this report, 

 the boundary -line between the Lignitic group and the well-marked Cre- 

 taceous strata is shown very clearly. We may say that very soon after 

 leaving the granite foot-hills, the Lignitic beds, at whatever angle they 

 may be found to incline, return to a nearly or quite horizontal position. 

 We may say that they incline at all angles from 5° to 70°, depending 

 upon their distance from the base of the mountains. 



From Colorado Springs to Golden City, the outcrops of the coal are 

 very rare; but, from Golden City to the Big Boulder, they are quite com- 

 mon, and the most productive coal-mines in Colorado are found there. 

 That beds of lignite or coal underlie the plain country far to the east, 

 there is hardly room to doubt. About ten miles east of Denver, on the 

 Kansas Pacific Bailroad, at a locality called Tousland, several shafts 

 have been sunk in the level prairie, and a thick bed of coal or lignite 

 was found at moderate depths. 



A section of the strata is as follows : — 



1. Clay, gravel, etc. 



2. Soft sand-rock 10 to 12 feet. 



3. Sandstone, with seams of coal varying from 1 to 18 inches in thickness, 



with G to 8 inches of sandstone between 30 feet. 



4. Coal, or lignite „ 6 feet. 



5. Sandstone, forming the floor of the mine. 



This is one of the most elaborately and elegantly prepared mines in 

 Colorado Territory ; but the coal contains so large a percentage of vol- 

 atile matter that it will probably not be made available for economical 

 purposes until the more valuable coal-mines in the vicinity are ex- 

 hausted. The great scarcity of timber all over this portion of the West 

 may, at some future day, render any kind of combustible material val- 

 uable as a fuel. One shaft sunk here is 245 feet deep, and a second one, 

 about a mile distant, is 145 feet deep. Both of them passed through 

 this 6-foot bed. The strata are horizontal. This bed is probably higher 

 up in the series than any of the beds that are wrought near the base of 

 the mountains. A few impressions of deciduous leaves were observed 

 here, but no other fossils of any kind. 



Again, near Platteville, on the line of the Denver Pacific Bailroad, 

 north of Denver, we find that several shafts have been sunk for coal 

 near the outer border of the group. About a mile south of Platteville, 

 a shaft was sunk 32 feet through the following strata, descending : — 



1. Clay : 8 feet. 



2. Seam of impure coal 1 foot G inches. 



3. Hard sandstone 10 feet. 



4. Blue quartzitic sandstone 1 foot 2 inches. 



5. Black carbonaceous clay, as roofing 5 feet. 



6. Coal ' 2 feet. 



7. Black clay, as a floor. 



The Hopkins mine is about a mile and a half east of Stoner's. Here 

 the shaft was sunk 05 feet. The mine is now abandoned. About two 

 3 H 



