coal. 35! 



The mine was opened in January, 1890, and has become an important local 

 producer. Two scams of excellent coal are present; an upper, 7.! to 9A 

 feet thick, and a lower, I feel thick, 32 inches of fire-clay and sandstone 

 separating them. A slope on the coal and cross-entries afford access to 

 the seam. The pitch of the beds is somewhat variable, but is usually below 

 30°. The general strike of the region is X. 20 c E. The extent of the 

 productive measures in this region has not been determined, the outcrop 

 being covered and the amount of boring having Keen slight While the 

 seam may continue southward, even beneath the mesa, to the north it is 

 soon limited by outcrop and erosion. 



nil. DAVIDSON DISTRICT. 



This is of little importance. It consists merely of a small patch of 

 coal, less than a square mile, that has escaped erosion on the northern slopes 

 of the Davidson mesa. It occupies a projecting table or flat composed of 

 coal measures on basal sandstones, the latter only extending beneath the 

 main valley to the north. The structure of the area is that of a very gentle 

 depression which occurs as a secondary and parallel flexure in the eastern 

 rim of the main syncline to the west. The axis of the secondary trough 

 lies in the eastern half of the district, near an old whim shaft. West 

 of it the strata have a Ion-- and gentle dip of from ;j° to 10° E., while 

 east of the axi> the dip is between 10° and 20 c \Y.. the latter degree that 

 of the dip of the basal sandstones on the eastern edge of the area. The 

 maximum depth of the coal along the axis of the syncline b about 60 feet. 

 The area is connected with the main held to the southwest by a narrow 

 hand of coal measures along the eastern rim of the general syncline. The 

 productive portion, except at this connection, is limited on all sides by the 

 outcrop of the beds. A section visible for a short distance down one of 

 the abandoned shafts shows the usual succession of beds, the clays and 

 shales predominating. But one workable coal seam has been discovered, 

 from 2 feet 8 inches to ;i feet thick. (Fig. C, PL XIX.; Its horizon can 

 not he positively stated, hut it probably overlies sandstone B, the upper 

 seams, of the Marshall area, having been but slightly developed or 

 altogether eroded. 



