8 



University of California Publications in Geology [ VoL 11 



it as the basal conglomerate of the Franciscan. J. 0. Nomland, 15 who 

 worked in the region during the summer of 1915, found that this con- 

 glomerate is actually younger than the Franciscan and that the posi- 

 tion has been reversed by a thrust fault which also brought up areas 

 of granite and old schist above the rocks of the Franciscan group. 



The supposed basal conglomerate of the Franciscan at Montara 

 Mountain has been found to be a later formation wedged in by 

 faulting. 10 



In spite of the non-discovery of actual contacts of these two groups 

 of rocks, it is almost certain that the Franciscan is not intruded by 

 the granite, but rests unconformably above it. The considerations 

 which prove this have been summarized by Professor Lawson. 10 



Evidence as to Age op the Franciscan in the California 

 Coast Ranges 



The Knoxville formation has commonly been regarded as repre- 

 senting the lowest Cretaceous, so that the stratigraphic relations as 

 outlined above, indicate that the Franciscan must be pre-Cretaceous. 



CONCLUSIONS BASED ON EELATION TO GRANITE 

 The Coast Range granite 17 is exposed at various points throughout 

 the Coast Ranges, and at the southern end of these mountains it ap- 

 parently continues through the region of Tejon Pass and Tehachapi 

 Pass into the southern Sierra Nevada. If the apparent relation be 

 the true one, then the Coast Range granite must be contemporaneous 

 with the granite of the Sierra Nevada. ' 



The figures 1 and 2 are diagrammatic representations of the 

 relations in the Sierra Nevada and in the Coast Ranges. 



Fig. 1 Fig. 2 



Fig. 1. Diagrammatic section showing the relation of formations in the Sierra 

 Nevada. Kc — Chico; Jm — Mariposa Slates; gr — Sierra Nevada Granite, intrusive 

 into the Mariposa Slates. 



Fig. 2. Diagrammatic representation of the relation of formations in the 

 California Coast Eanges. Kk — Knoxville ; Fr — Franciscan Group ; sp — serpen- 

 tine; Gl — Gavilan limestone; gr — Coast Eange Granite. 



is J. O. Nomland. Unpublished Manuscript. 



is Lawson., A. C, San Francisco Folio, U. S. Geol. Surv., Folio no. 193, 1914. 



17 In this discussion "granite" is used as a general term to include the 

 various plutonic types which make up the Coast Range and Sierra Nevada 

 granitic areas. 



