coal. 337 



RALSTON ' l;l'l K I'l-I RIl I. 

 Ralston Springs mine. Tllis IS located ill till' ValleYof Vail Libber (')eok, 



and until recently was a large producer. The shaft lies immediately 

 north of a sharp Laramie knoll in the middle of the valley, ami is 

 sunk to the west of the overturned strata. The strike of the measures 

 along here is very constantly X. 17° Iv, the dip being 65 ami so 

 westward, becoming vertical in depth. The seam is reported 8 feel thick 

 and without partings. South of the shaft, in the vicinity of the Laramie 

 knoll, the coal is said to be so interstratified with sand and clay as to be 



worthless. Northward it has been extensively developed and, it is stated, 

 promises to hold width and quality to the end, at the east and west fault 

 marking the southern line of the disturbed area about the Ralston dike. 



The disturbed area east of Ralston dike. TllO COal measures between the tWO ea~t 



and west faults bounding this area have been horizontally displaced con- 

 siderably over half a mile. Owing- to this and the nonrecognition of the 

 faults, early explorers were led to believe that the coal was Fox Bills, since 

 characteristic Mactra had apparently been found above it. In reality, how- 

 ever, the Mactra occur in the dislocated beds north of the southern fault, 

 beneath the coal, but east of an extended line of coal outcrop from the 

 Ralston Springs mine ; hence the error. The fault remained undiscovered 

 until the present explorations. The coal measures of the disturbed area 

 dip in a general way eastward, but where they have been exploited, at 

 the southern end, are greatly fractured. North of the area, beyond the 

 influence of disturbance, the region of the Ralston ('reek mines is reached, 

 these having been among the greatest producers in early times. 



The Ralston Creek mines. — These embrace two shafts, one in the northern 

 bluff of the valley, the other on the prairie a short distance to the south. 



They attained a depth of L12 feet below creek level, but have been closed 

 for many years. There are said to he two workable coal seams: the 

 western, near the base of the measures, 9 feet thick: the other, •_'."> feet to 



the east, from 14 to is feet thick.' The measures have a N. 4 W. strike, 

 continuing between this and north for several miles northward, and to the 

 south nearly to the fault along the northern edge of the disturbed area 



'U. S. Geol. andGeog. Survey of the Territories, P. V. Harden, Report on Colorado, 1-7:;. p. Il'.j. 

 MOH XXVII 22 



