418 B. WILLIS — SOME COAST MIGRATIONS, CALIFORNIA 



phenomena of the region, but also for helpful discussion of their inter- 

 pretation. 



Professor A. C. Lawson * has described the geology of Carmelo bay just 

 south of Monterey, a district which adjoins on the north that herein 

 referred to and which includes the Santa Lucia granite, the youngest 

 member of the Coast complex hereafter defined. My observations are in 

 general in accord with those made by Lawson at Carmelo bay and by 

 Fairbanks farther south. 



The present Scene 



Point Sur, a prominence of the California coast, lies 24 miles south of 

 Monterey. From it the coast stretches 57 miles southeast to Piedras 

 Blancas. Along this section extends the westernmost of the Coast 

 ranges, locally known as the Santa Lucia range, which attains elevations 

 of 4,000 to 5,000 feet. The mountains present a bold front to the ocean, 

 precipitous, it is true, only near sealevel at isolated promontories, but 

 generally steep. Ravines gash this front deeply. In general, the aspect 

 of the mountain slope is that of mature topography. In detail, there are 

 variations of form significant of successive episodes of uplift. 



Near Slate Springs, 35 miles southeast of point Sur, there are two 

 basal conglomerates — the one, that which is being formed by the waves 

 which now dash against the rocky shore; the other, that which was 

 similarly formed when the} 7 broke on a shore of Mesozoic date. The 

 present conglomerate is the beach ; the older conglomerate is the base 

 of the Franciscan or Golden Gate series, and rises in cliffs several hun- 

 dred feet above the beach, the strata dipping 70 to 80 degrees to the 

 southwest. The present conglomerate and the older one both consist 

 largely of pebbles and boulders of a still older complex, which will be 

 called the Coast complex. On the summit and eastern flank of the 

 Santa Lucia range occur strata which are much younger than the Fran- 

 ciscan formation. They constitute a group whose members bring the 

 record down to late Neocene (Pliocene) time. 



The sequence thus briefly indicated includes (1) the development 

 of the Coast complex; (2) profound erosion of the Coast complex; (3) 

 deposition of the Franciscan conglomerate, sandstone, and shale ; (4) oro- 

 genic movements, which resulted in deformation of the Franciscan forma- 

 tion ; (5) erosion of the Coast complex and Franciscan rocks, which is 

 partially represented in later sediments ; (6) evolution of the present 

 mountain system and coastal front. 



*The Oeology of Carmelo bay. University of California, Hull, of the Dept. of Geology, vol. i, 

 pp. 1-50. 



