NEOCENE STRATIGRAPHY. 289 



even running into the thousands. These faults and nearly 

 all the structural features have a strike of about north- 

 west and southeast. 



As a rule the Monterey-Merced series are only gently 

 folded, the strata usually having a dip lower than 45°, 

 but locally the dip is frequently found to be as high as 

 75° or 80°. The axis of greatest disturbance seems to 

 have been in about the same line as in the early Miocene 

 upheaval. During the Merced period a volcanic outflow 

 of andesite took place in the area of the foot-hills near 

 Stanford University. Just above this is a layer of barna- 

 cles, cidaris spines, etc., and in places Pholas borings in 

 it, with other evidence showing that the outflow formed 

 later a part of the shore line. Other evidences of slight 

 movements during the Monterey-Merced period are found 

 in the distribution of the two formations. In places the 

 Monterey series lies upon the granite, in others the granite 

 or Pescadero series underlie the Merced series. 



The folding, as a rule, has been sharper on the side of 

 the mountains toward the bay. The fossils there are 

 generally distorted and the strata are firmer and more 

 consolidated. The most noticeable faults are also all on 

 the northeast flank of the mountains. Along the ex- 

 posure on the Seven Mile Beach, faults of from a few 

 feet or inches up to ten or twenty feet are frequent; but 

 aside from those only major faults have been recognized, 

 and these partly by the distribution of the formations, 

 partly by topography. There appear to be two main di- 

 rections of faulting, parallel with the strike of the moun- 

 tain, and in a nearly due east and west direction. The 

 strata are generally tilted up at a high angle, often being 

 perpendicular, but usually having lower dips as we recede 

 from the line of greatest disturbance. 



The Quaternary was a period of oscillation. During 



2d See., Vol. V. ( 19 ] August 1, 1895. 



