138 (.KOLOtiY OF THE DENVER BASIN. 



give ;i general relative displacemenl of the two formations of about 300 or 

 325 feet, I mt this amount varies somewhat from point to point, especially 

 toward the ends of the l';uilt. From memoranda of borings for coal just 

 east of the fault and L| miles south of Erie, furnished by a Mr. Van 

 Valkenberg, it is possible that the total displacement may be increased to 

 between 350 and |-_\ r > feet. 



The Baker faun. — This extends in ii direction N. til 35' E. from the bot- 

 toms of Rock ('reek, near its confluence with Coal Creek, to a point 

 within a short distance of the summit of the divide between Coal and 

 Little l>rv creeks, southeast of Erie, passing a few hundred feet southeast 

 of the Baker mine. The fracture originated in one of the simple folds 

 which are common upon this face of the divide, but whether it is of the 

 normal or reverse type can not be determined. In a gulch a half mile 

 northeast of the Baker mine it is reverse, the plane inclined 60 northwest, 

 but this may lie local. The Stratigraphic displacement varies. For the 

 entire length of the fault, upon its southeastern side, nothing lower than an 

 undetermined horizon in the upper Laramie clays appears; on its north- 

 western, iii the vicinity of the Baker mine, these beds are opposed by the 

 coal measures; one-halt' mile northeast, for a distance of half a mile or 

 more, by the Fox Hills and the basal sandstones of the Laramie; beyond 

 this, >till to the northeast, l>\ upper Laramie. From this the greatest 

 recognized displacement is in the apposition of the Fox Hills to upper 

 Laramie, 250 feet, but it is doubtless more than this in places. The 

 strata on either side of the fault line are locally somewhat fractured, 



but they rapidbj regain their general, northwesterly dip of ~> to 25 . to 

 be again folded, ami perhaps faulted, at no very great distance beyond. 



The economic effect of this fault has been to limit the southeastern 

 extent of the small workable area of coal known as the Baker field by 

 depressing the strata on this side of it to an unknown depth. No solution 

 to the problem of depth is to be found on the surface, and there remains 

 but one resource, boring. 



The Baker cross-faun. — This is n short fault across the point of ground in 

 the angle between the Baker and Coal ('reek faults. Its trend is S. 65 

 to 7<» F. The inclination of its plane is unknown. The downthrown side 



