270 University of California Publications in Geology [Vol.8 



resistance of the older rocks. Late in the Tertiary or early in the 

 Quaternary the northeast side of the Santa Ana Range became the locus 

 of a fracture in the earth's crust and the range was tilted as a block 

 to the southwest, with consequent renewal of stream-cutting on the 

 mountain mass. Some of the higher well-defined terraces on these 

 streams flowing to the southwest may indicate intermittence in the 

 faulting movements. Because of the amount of work which the streams 

 have accomplished it is believed that the faulting by which the range 

 has been, and perhaps is being, uplifted commenced before latest 

 Pleistocene time. The last movements in this region are recorded in 

 the marine terraces along the coast and by correlative stream terraces 

 of the San Juan and its tributary, the Arroyo Trabuco. 



SUMMARY 



1. The Chieo of the Santa Ana Mountains is divisible into at least 

 three and possibly four fauna! zones. 



2. The Martinez Eocene appears to represent the lower and middle 

 portions of the typical Martinez of the northern part of the state. 



3. The Martinez group rests with marked unconformity upon the 

 Chi co. 



4. The Tejon is very limited in extent and it is found in uncon- 

 formable contact with the Chico. Areal and structural relations show 

 that there was a great time-interval between its deposition and that of 

 the Martinez. 



5. The Miocene contains both the Turritella inezana and the Turri- 

 tclla ocoyana zones. The faunas obtained from these two zones are 

 more closely related than was previously recognized. 



6. The Chico, Martinez, Tejon. and Vaqueros all contain admixtures 

 of land-laid deposits. Coal in paying quantities is found in the Tejon. 

 Lignite seams in the Chico of Silverado Canon have been mined for 

 coal. A little coal was found in the Martinez area near Santiago 

 Creek. Brackish water deposits as well as marine occur in both the 

 Martinez and Tejon. It is evident that all three groups were largely 

 littoral deposits. 



7. The Ferris Peneplain may be the correlative of the Ricardo 

 Peneplain of the Mohave region of the Great Basin. 



Transmitted March 31, 1914. 



