322 KRAMM— SERPENTINES OF THE CENTRAL [June 6, 



Rocky Creek south to its headwaters, forming a series of low peaks 

 to the east of the creek. Occasional outcrops from here have a 

 northwest-southeast trend, establishing a connecting link with the 

 main body of serpentine, which following the same general direction 

 gradually expands to a width of four miles, passes to the south of 

 Knoxville, and finally terminates about three miles southeast of 

 Knoxville in a series of rugged outcrops. 



The area as a whole presents a monotonous aspect. One sees 

 a series of rocky ridges densely covered with brush and here and 

 there a tree. 



In the northwest, Rocky Creek cuts its way through the area 

 and at places exposes steep walls of serpentine a hundred and 

 more feet high, rising almost perpendicularly. The bed of the creek 

 is strewn with big boulders which sometimes reach a diameter of ten 

 feet. This is especially noticeable near the Shamrock Mine. 



In the southwest Hunting Creek has cut a deep narrow canyon 

 which gradually widens out towards the south, and into which enter 

 a number of smaller canyons formed by tributaries. As at Rocky 

 Creek the serpentine here is exposed presenting steep walls, and its 

 debris covers the creek bed. 



The headwaters of Davis Creek which drains to the north, and is 

 a tributary to Cache Creek, have left their imprints upon the topog- 

 raphy. Excellent opportunities for collecting fresh specimens are 

 afforded by these drainage channels. 



In many respects the serpentine resembles the one found at 

 Sulphur Creek. It however presents a greater variety of colors. 

 They vary with the degree of weathering the rock has undergone 

 and the amount of iron it possesses. Upon fresh surfaces it is 

 usually a dark green or almost black. The first indication of 

 weathering is a yellow or a red color. Exposure to the atmosphere 

 and the sun bleaches the serpentine and causes a decrease in hard- 

 ness. A greenish-white slippery mass which resembles talc is the 

 end product. 



While here, as in the Sulphur Creek region, the shearing action 

 is intense, .and manifests itself in many slickensided fragments, the 

 nodular variety of serpentine is not represented to any extent. This 

 indicates a more homogeneous original mass. 



