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CRANDALL— SAN FRANCISCO PENINSULA. 



tion is exposed in the cliffs north and south of San Pedro Point 

 for which they are named. The shale is very similar throughout, 

 being grayish black, close grained and hard. It is in thin layers 



Fig. I. 

 San Pedro Point, showing the beds called San Pedro shale dipping northeast. 



varying in thickness from an inch to twelve or fourteen inches and 

 occasionally interbedded with fine and coarse grained sandstones 

 that grade into granite-bearing conglomerates which are not per- 

 sistent. The beds weather into oval forms, the outer surface of a 

 lump often being marked with ridges that define the oval forms 

 into which the shale breaks. 



3. Liuicstoncs. — Overlying this shale series is a limestone par- 

 tially crystalline in general, and wholly so in places, but more com- 

 monly interbedded with jasper layers approximating an inch in 

 thickness. This limestone occurs in Calera \'alley where it forms 

 several small hills, and it continues intermittently toward the south- 

 east, the largest area being on Cahill Ridge. No work was done 

 upon this limestone but it has been described by Professor Lawson 



