68 : THE MOUNTAINS OF COLORADO. 
in these rich pastures, but the buffalo has been driven away. 
When, in 1844, Fremont visited the South Park, herds of these 
animals blackened the surface, and their well-beaten trails afford- 
ed the most practicable route through the region ; but now they 
do not even approach the foothills. 
The Utes use these parks during the summer as cow lodges, but 
as winter approaches the herd is driven down to the plain. 
Grotocy. To comprehend the geology of the Rocky Mountains, 
where the forces of metamorphism have been so powerfully ex 
erted, it is necessary at the same time to study the geology of the 
Plains, where the strata repose nearly horizontally, and are abun- 
dantly charged with fossils. Starting at Kansas City, we first 
counter the Coal Measures, which continue to Fort Riley. Here 
occurs a drab-colored limestone associated with marls, which 1 
regarded as the equivalent of the Permian. Next succeeds a series 
of bright red and green marls, seen at Salina, which may be Tri- 
assic. Above this formation comes the Cretaceous occupying 4 
broad zone nearly coterminous with the plains, conspicuously dis 
played at Ellis, Fossil Creek, and Fort Wallace. The Miocene 
tertiary abuts against the foothills and extends to the east of Der 
ver. At Golden City, the strata of this formation are tilted up 
vertically, thus showing that within comparatively recent times, 
this region has been subjected to violent displacements. It 
characterized by heavy deposits of coal (lignite) which is succe 
fully mined at Golden City, on Ralston’s Creek, South Boulder and 
other streams descending from the mountains. The beds are ten 
ten to'fourteen feet thick—an undue expansion which would i an 
cate that they are pockets, instead of persistent seams. The : 
is bright and glossy, but crumbles on exposure to the aif" 
even. when burned in a grate. It contains from twelve st fifteen . 
per cent. of hygrometric moisture which must be expelled in 0% 
bustion at the expense of the fixed carbon, and therefore prev™ 
it from acquiring that concentrated heat necessary in ™ urgi¢ 
operations. It answers well for household purposes and for: 
motives, and in such a region where wood is scarce, its eco! 
cal value can hardly be over estimated. pe 
As we enter the foothills, layers of brick-red sandstone arè- 
served which, although destitute of fossils, Hayden is dispose 
regard as Jurassic. There is also seen a drab-colored lim 
