QUARTZITES AND CANONS. 59 



Avhich cuts across all of the creeks north of Harney Peak, occasioning in 

 each one an intricate, precipitous and exceedingly rough canon. This 

 ridge and these canons are due to a series of quartzite strata, which by 

 their hardness and durability preserve the interbedded slates from rapid 

 erosion, and not only retain their own supremacy in the topography but 

 restrain the creeks from opening broad valleys. 



West of this prominent geological edge there is a stretch of country 

 which is rolling in character and nowhere very rough. In passing it 

 the creek bottoms often spread out into valleys of considerable extent, 

 and the divides between them are neither rough nor steep. Its smooth 

 character marks it as the outcrop of the soft slates rarely interrupted by 

 harder strata. 



On the west of this strip the headwaters of the various branches of 

 Spring and Rapid Creeks are secluded in canons precisely similar to those 

 on their lower courses and due to a similar cause. A series of quartzite 

 strata resists the wear of the elements and conserves a belt of peaks and 

 ridges. 



Quartz seams of a thickness varying from less than an inch to many 

 feet are numerous in the more silicious slates. Usually they run parallel 

 with the stratification but do not have the lenticular, wedging character 

 noticed in the small quartz veins of the micaceous schists. In many places 

 the quartz is interlaminated with the slate in thin, alternating seams. Some 

 of the quartz seams appear to be true veins, formed by the collection of the 

 quartz along lines of separation of the strata, and such can be traced long 

 distances. Commonly they run parallel with the bedding, but in a few 

 instances they have been found cutting across the strata at a right angle, 

 following cleavage or jointing planes. They are frequently highly ferru- 

 ginous, so that on their decomposed edges they are made by the weathering 

 out of the quartz to appear like ledges of brown hematite ore. The quartz 

 of the seams is highly crystalline, is usually translucent or opaque, and 

 when unstained by iron is milk-white in color. 



A prominent deposit, segregation, or accumulation of quartz is found 

 two or three miles east of Custer Peak, to which the name of Jasper Hill was 

 given. It is irregular in shape, about 200 feet in height, and without any 



