72 



University of California Publications. 



[Geology 



along railroad and road cuts. The contact between these beds 

 and the Merced is, therefore, not clear and the structural 

 relations remain indeterminate. 



It is probable that this formation is the same as the Santa 

 Clara formation described by Branner 9 farther north on the 

 east flank of the Santa Cruz range ; but it resembles both in its 

 general characteristics and in its approximate position in the 

 geological scale the earlier described Orindan of Lawson 10 and 

 may perhaps be the correlative of the latter. The entire contem- 

 poraneity of the fresh-water beds of the Pajaro Valley region 

 and the Merced formation is doubted. While it is probable 

 that in part they are contemporaneous, it seems impossible that 

 the two should be so well developed in such close proximity as 

 is here noted and yet be entirely of the same period. The writer 

 believes that the lower part of the fresh-water formation is 

 contemporaneous with the upper part of the Merced but that 

 the former lies, at least in the Pajaro Valley, above the lower 

 Merced. 



In the section of the fresh-water formation exposed for a 

 mile south of Sargent along the railroad track, the beds dip (see 

 pi. 16, fig. 1) 21° to the south. In this whole section in its lower 

 part there are two thin beds containing marine fossils, indicating 

 brief invasions of the sea over the region of delta accumulation. 



PLEISTOCENE AND EECENT EOKMATIONS. 



There is a marked unconformity between the fresh-water 

 formation and the recent alluvial deposits. No gradation, as has 

 been noted farther north between the Santa Clara beds and the 

 alluvium of the Santa Clara Valley, exists in the Pajaro Valley 

 region. Very recent changes, which have entrenched the streams 

 below the base of the alluvial deposits, have exposed the actual 

 contact between the disturbed fresh-water formation and the 

 more recent beds; and the unconformable relations are striking. 



All the larger streams have been entrenched in their own 

 alluvial deposits, thus exposing sections. The river gravels along 

 La Brea and Pescadero creeks contain stumps of Sequoia. 



s>U. S. G. S., Folio 163. 



io Univ. Calif. Publ. Bull. Dept. Geol., 2, 1902, pp. 371-374. 



