HAVALLAH RANGE. 683 



exposes very simllarr interstratified beds dipping westwai-d; but to tlie south 

 of the latter stream, the small body of granite already described comes in, 

 and tbe beds under its influence probably again dip toward the centre of 

 the range. 



From Bardmass Pass southward, the Upper Triassic beds, no longer sub- 

 jected to the influence of the underlying rigid quartzite, extend from Grass 

 to Ragan's Valley with low gentle rolls, forming a synclinal and anticlinal 

 fold. At the western entrance to the pass, a gray compact sandstone over- 

 laid by limestone is exposed, dipping eastward, which soon assumes a reverse 

 dip, while along the eastern base an anticlinal axis exposes the sandstone in 

 smooth, rounded, grassy hills with few outcrops, inclined again to the east- 

 ward, but with the limestone, which has been for the most part carried away 

 by erosion, occurring only in small isolated patches. 



On the oj)posite side of Eagan's Valley, the beds form a steep cliff to 

 the west, but incline eastward with gentle angles, shallowing in dip till the 

 limestones of the summit lie nearly horizontal. A short distance to the 

 southward, near Pollard and Dale Canons, the two distinct ridges come 

 together, and form a single narrow range of highly metamorphosed slates, 

 shales, and schistose quartzites, and in place are so much altered by twist- 

 ings and flexures as to resemble eruptive masses in their great variety of 

 color and rapid change in physical aspect. Many of the rocks have a scori- 

 aceous cinder- like appearance, and might easily be mistaken for volcanic 

 products but for their parallel and banded structure in broad masses, and 

 the evidences they afford of transition from well-developed slates and quartz- 

 ites. The strike of the beds agrees approximately with the trend of the range, 

 varying from north 5° west to north 10° east. In dip, recorded observa- 

 tions gave from 15° to 30° to the west. 



An interesting geological feature of the range, which is evidently closely 

 related with the complicated structural conditions of the sedimentary strata, 

 is the occuiTence of numerous narrow dikes of diorite in the region of Dale 

 and Pollard Canons, standing at high angles, and nearly parallel with the 

 strike. They vary considerably in texture and superficial aspect, but in 

 mineral composition exhibit the same constituents, mainly plagioclase and 

 more or less altered fibrous hornblende. One variety has a dark-green color, 



