MVRVD.-EJ GEOLOGY METAMOEPHIC ROCKS OF THE MOUNTAINS. 141 



of such remnants are carefully noted and platted on tlie map, they are 

 invariably cousisteut among themselves in indicating a definite struc- 

 ture of the whole, and accord with the structure that may he indicated 

 by neighboring schists and other masses of undoubted bedded rocks. 

 Thus, suppose a horizon of exceedingly well-bedded quartziferous and 

 mica schists to be under or overlaid by granites which possess in general 

 no distinct structure, and that the foldings have been such that a sharp 

 anticlinal has been formed with its axis dipping steeply to the north. 

 The outcropping edges of the schists would thus appear, forming an 

 angle or curve, with the apex directed northward and widening out to 

 the south, while the beds dipped off outward to the west, north, and 

 east. JSoyv going among the granites above and below, and noting care- 

 fully the directions and dips of all the little evidences of structure found, 

 however insignificant, it will be found that they, too, all accord with the 

 zone of schists, and indicate precisely the same sort of fold. For many 

 miles, often, such a fold may be traced in this manner, perhaps retain- 

 ing the same characters as it is clearly shown to have in the schists, or 

 increasing in sharpness or finally dying out entirely and disappearing. 

 And when it is observed that the zone of schists, when traced longitu- 

 dinally, may also be formed, changed into a similar granite region, with 

 the same indications and remnants of bedded structure, the proof be- 

 comes conclusive. Indeed, so constantly and without exception did 

 this agreement of isolated observations occur, whenever chance and time 

 threw a sufficient number of observations into a small enough area, 

 that observations at first looked upon as doubtful, if not misleading, 

 finally came to be regarded as trustworthy evidences of structure, and 

 the conclusion drawn that, however extreme and profound the metamor- 

 phism may have been, the tendency of its action was to produce a homo- 

 geneous or structureless mass, and niaver such as to impress on the rock 

 definite indication as of a new bedding; and that where indications of 

 structure do accur they simply rej^resent the remnants of bedding that 

 have not been obliterated by the metamorphism, and thus indicate the 

 original structure of the whole mass. Many observations that were at 

 first considered as wholly questionable and provisional, were afterward 

 found to accord with trustworthy data found not far off. Even a much 

 less expected indication of bedding was noticed at many points, though 

 it was by no means accepted as a trustworthy one. When strata of 

 varying degrees of hardness are inclining somewhat, and subjected to 

 erosion, the irregularities of surface formed are almost always stee^jest 

 on the sides that exhibit the edges of the strata, the slopes with the 

 inclination of the strata being usually much the more gentle, as shown 

 so repeatedly in the hog-backs. Now, over considerable granite or 

 gneissic areas, especially in theregion near Turkey and Last Resort Creeks, 

 the at first apparently structureless granite hills presented their steepest 

 faces to the south, or southeast, or southwest, and in nearly every case 

 the remnants of structure found here and there in them, and which 

 conformed in plan to the plainer schists at the north, bore the normal' 

 relation to the form of the hill, i. e., dipped with their gentler slope, and 

 showed their edges on the steeper ones. It seemed strange that such 

 a simple topographical feature should be preserved in such much changed 

 rocks. 



Thus it became certain that all the great masses of rock which here 

 compose the archa;an areas of the district, the granites inclusive, were 

 metamorphosed in situ, and that the latter, as a whole, must be consid- 

 ered as indigenous in its character. This metamorphism would seem to 

 have been deep-seated. Not only would its nature and extent, judging 



