HAVALLAH RANGE. 681 



few globulitic, amorplious particles, like the basalt breaking through the 

 granite already described. 



The massive beds of the main portion of the range appear to have under- 

 gone considerable displacement and folding, producing a number of local syn- 

 clinal and anticlinal axes, which renders the structure somewhat complicated 

 and difficult to work out ; the broader features, and many of the details, 

 however, will be found in the following short description. West of E,agan's 

 Valley, the main mountain-mass consists of the underlying quartzite, 

 which forms the summit of Signal Peak, falling off rapidly to the north, but 

 extending southward for about 15 miles in a roughly diamond-shaped 

 body. It rises rapidly above the surrounding foot-hills, frequently with 

 steep walls, and has a broad, gently inclined, table-like summit, which is 

 divided into two ridges, separated by the caiion and basin of Clear Creek. 

 The eastern ridge dips to the eastward, and the one on the opposite side, 

 which is the higher, probably dips to the westward, although our observa- 

 tions are somewhat contradictory. Such a structure would give an anticli- 

 nal fold to the quartzite, the deep cai3on of Clear Creek lying in the axis, 

 and in a great measure accounts for the trend of the canon being approx- 

 imately parallel with the strike of the quartzite beds. 



This quartzite, which is distinctly bedded, possesses a vitreous lustre, a 

 compact texture, and a bluish to steel-gray color. It is an exceedingly 

 dense, tough rock, breaking under the hammer with a conchoidal fracture. 

 Under the microscope, the quartz-grains are seen to vary greatly in size, and 

 to present smooth rounded surfaces. Specimens from two localities show 

 that the grains carry large numbers of fluid-inclusions. 



The beds have been referred to the Lower Triassic, or the horizon of 

 the Koipato quartzites. It is not quite clear, however, that they underlie 

 conformably the Star Peak Triassic, and they may belong to a much older 

 formation, possibly of the same age as the dark quartzite beds of Sue Peak 

 in the Battle Mountains, the true position of which is somewhat doubtful. 



Overlying the quartzite body on all sides, forming the foot-hills, are the 

 blue limestones, with the iuterstratified beds of sandstones, slates, and shales. 

 On Gold Run Creek, between the quartzite and granite, the beds consist of 

 highly metamorphosed siliceous slates, much folded and twisted, dipping 



