86 SOUTHERN CALIFORNIA GEOLOGY 



mentary rocks which once covered the originally deep- 

 seated granitic rocks and which were denuded as the 

 blocks uprose. 



Many details of these highlands are to be mapped 

 — sufficient to entertain microgeologists for years to 

 come. We regret that space does not permit the 

 insertion here of the more lengthy descriptions of these 

 great features which I have in manuscript. 

 TRANSVERSE HIGHLANDS OF THE 

 DESERT SIDE 



It is only within the past three months that I have 

 had maps of the Desert Side whereby its physiography 

 and structure may in a degree be interpreted. By 

 their aid I have been enabled to incorporate the greatly 

 reduced outlines of the mountains on Plate 1. 

 There are physiographic complexities on the Desert 

 Side which we do not as yet venture to interpret. 

 These are produced by the meeting and, at times, 

 crossing, of the Great Basin, Transverse Belt, and 

 Northwest-Southeast trends in that region. The East- 

 West fault lines of the Transverse Belt continue 

 through the region with undiminished displacement, 

 however, as is more fully discussed in the chapter on 

 structure. Some of the highlands, like the Little San 

 Bernardino and the Pinto, are undoubtedly fault block 

 uplifts along the East-West structure.^ 



^Note: The presence and abnormal character of the features of the Trans- 

 verse Belt were first recognized by W. P. Blake, some seventy-five years ago 

 (See Pacific Railvi-ay Reports for Route along the 35th Parallel, Vol. 5, PI. 3, 

 Washing-ton, 1856). 



His descriptions of some of the geographic and geologic features of South- 

 ern California are fundamental and classical. The significance of this most 

 important structure was but faintly recognized, if at all, by succeeding geol- 

 ogists. Later studies by the writer, however, convince him that Professor 

 Blake gave us an insight into a feature of fundamental and far reaching 

 importance to the understanding of the paleogeography and geology of Cali- 

 fornia. One reason for this omission has been the absence of adequate topo- 

 graphic maps east of the longitude of the San Gorgonio Pass. These now 

 (1927) have happily been supplied. 



