BUCKSKIN SECTION. 129 



very variable in thickness, of gray quartz-porphyry, like the Lincoln, but 

 without its large feldspars and with its basic silicates generally much altered. 

 Between this and the Archean are forty to fifty feet of white saccharoidal 

 quartzite, with a thin bed of fine-grained conglomerate at the base, wherever 

 the base can be distinguished. The Archean here consists of a dark mica- 

 gneiss, approaching a mica-schist in structure. 



The dark, more or less perpendicular lines on the sketch represent 

 shallow ravines on the face of the cliff, which are generally fracture planes 

 across the beds, accompanied by a certain amount of dislocation. The 

 principal ravine is that to which the double line over the de'bris pile (which 

 represents a raised tramway for carrying down ore) leads, and in which are 

 the now deserted workings of the Northern Light mine. This fault had a 

 movement of about fifteen or twenty feet, and the ore seems to have been 

 found in the crevice of the fault. These small faults were probably pro- 

 duced by the general dynamic movement in which the rocks were folded, 

 and it will be noticed in the sketch that the intrusive sheets are faulted in 

 the same degree as the inclosing sedimentary beds. About half a mile west 

 of the point represented on the sketch is a prominent fault on the cliff, with 

 an upthrow to the west of about one hundred feet. The direction of this 

 fault, as of the minor fracture planes in the sketch, is between north and 

 northeast, which corresponds with those observed near the Criterion mine, 

 on the opposite wall of the gulch. 



East of the Northern Light mine the beds slope rapidly down in a 

 graceful curve to the bed of the gulch, in which only the outcrops of the 

 harder and more silicious beds project above the gravel. The former min- 

 ing town of Buckskin Joe, the oldest settlement in this region (now, like its 

 companions, Quartzville and Montgomery, consisting mainly of deserted 

 cabins and mill foundations), is situated on the outcrops of the base of the 

 White Limestone. On the south side of the creek, a little above the town, 

 is the once famous Phillips mine, an open trench, some twenty feet wide and 

 in places as many deep, cut in an immense concentration of iron pyrites along 

 a bedding plane of the Cambrian quartzite. In one place a decomposed 

 quartz-porphyry is found on the hanging wall, which apparently cuts across 

 the formation, as it is also found in the creek bed near the bridge at a some- 



MON XII 9 



