SANDSTONE DIKES OF UTE PASS. 123 



on the next spur (11), which rises directly above the 

 Barker House. A small prospect hole at the head of the 

 first bench shows the coarse, soft Fountain beds in slti'i. 

 The sandstone dike, one hundred feet or more in width and 

 coarser than the normal, outcrops more prominently here, 

 giving the second bench an almost precipitous front. These 

 breaks in the profiles of the spurs are directljMn the course 

 of the Ute fault as followed from the second tunnel ; the 

 topography and geologic structure are evidently in agree- 

 ment ; and the sandstone dikes closely accompany the 

 fault. 



The spur running southwest from the Midland Depot 

 (12) is drift underlaid by Fountain beds to the head of 

 the first main bench, about one thousand feet (estimated) 

 from the railroad. Here, on the steep slope or front 

 of the seccmd bench the great sandstone dike has a width 

 of fully one hundred and fifty feet. Both the north and 

 «outh granite walls are obscurely exposed, fifty to one 

 hundred feet of granite separating the dike from the 

 great fault. Some of the dike rock is quite coarse and 

 indistinguishable from the normal Potsdam ; and the dike 

 is divided by some very prominent slickensided shear 

 planes. As usual, the prospect openings afl^ord valuat)le 

 exposures of the geologic structure. 



The first important gulch east of Ruxton Creek is that 

 running south-southwest from the Midland Depot. On the 

 western slopes of this gulch,* above the main detrital 

 cones, the dike saudstone outcrops very strongly on 

 several spurs, extending about one-fourth mile up the 

 gorge from its mouth, or approximately one half mile 

 from the railroad. Good exposures are aftbrded by 

 road-cuttinsfs ; and the indications are tavorable to the 

 view that the great dike turns slightly on reaching the 

 ffulch and extends with a breadth of one hundred to two 



