350 University of California Publications in Geology [Vol. 13 



Similar schists in Dry Morongo appear to be made up of long 

 continuous bands alternating grey, white, and black. These 

 usually exhibit much contortion and crumbling. Because of the even- 

 ness of the banding, the individual bands showing but little tendency 

 to pinch out, they at first appear to be sedimentary ; but that similar 

 well defined bands may be formed in another manner, may be seen 

 near the head of the canon. Small pegmatite dikes less than an inch 

 to three inches thick are found ramifying through the schist. From 

 this simple relation gradations may be followed to schistose rocks in 

 which these small dikes have been drawn out into long bands. The 

 continuity of these for distances of 20 to 30 feet and the resemblance 

 of the mass to altered sediments is truly remarkable. 



These schists extend northward to Big Meadows and Big Morongo • 

 Creek, where they are cut off by granites. The line between the 

 granites and schists is not definite, but the schist area by an increasing 

 amount of granite becomes a granite area. 



As a whole, this great mass of schists has little in common with the 

 limestone and quartzite to the north. Their general aspect — their 

 high degree of metamorphism, intense folding, and intimate association 

 of sediments with granitic rocks so altered as to resemble them — all 

 are indicative of a vastly older complex. Furthermore, these granites 

 are of many varieties while most of the granite intruding the lime- 

 stone and quartzite is of much the same general character. True, 

 there are small areas of other varieties cutting these sediments, but 

 there is no proof that they are the same as the great heterogeneous 

 mass so intimately associated with the schists. In Burns Canon the 

 granites and small areas of schist are cut by so many pegmatite dikes 

 that from a distance their prominence, due to differential erosion, gives 

 the whole mass the appearance of a sedimentary formation. Lindgren 6 

 believes that in the Cordilleras this association is confined to pre- 

 Cambrian rocks. On this criterion there is a possibility that some of 

 the schists to the southwest may also be pre-Cambrian. 



On the other hand, as already mentioned, there are parts of the 

 quartzites and interbedded schists so altered that they duplicate a 

 great many varieties of the schists to the south. East of Baldwin Lake 

 the Saragossa quartzite has a general dip of about 40° southwest and 

 individual strata may be followed, almost without a break, for six 

 miles ; but locally portions of the same mass are crumpled and folded 

 in such a complex manner as to come up to the ideal conception of 



s Lindgren. Waldemar, Dana commemorative lectures on problems of Ameri- 

 can geology, Yale University, December, 1913, p. 241. 



