Louderback: The Monterey Series 



211 



Los Angeles, Arnold, 1907. — In the part dealing with "the 

 Los Angeles Oil District," Arnold"' 3 uses the same term Puente, 

 and divides the Miocene representatives into the "Puente sand- 

 stone" and the "Upper Puente shale." These he believes to 

 correspond to the deposits of the same name in the Puente Hills. 

 But his Puente sandstone here is fossiliferous and yields a fauna 

 that he considers to be characteristic of the "lower Miocene 

 throughout the southern San Joaquin Valley and as far south 

 as the Santa Ana Mountains" and "equivalent 34 in general to 

 the Vaqueros sandstone of central California." It apparently 

 corresponds to the Agasoma zone and the stage of Turritella 

 ocoyana and T. variata. 



The lower portion of the "Puente sandstone" is described 

 as argillaceous, and as possibly equivalent to the "lower Puente 

 shale" of the Puente Hills. 



The "upper Puente shale" is said to consist of alternating 

 sandstones and shales throughout, the lower 1000 feet being thick 

 bedded and grading into the Puente sandstone with "no sharp 

 line of demarcation," the upper thousand feet thin bedded. 

 Most of the shale in the lower part of the "Upper Puente shale," 

 and also "many of the shale beds interstratified with the Puente 

 sandstone?" are of the hard white siliceous variety character- 

 istic of the Monterey shale in the Coast Range." They carry 

 abundant remains of micro-organisms. 



We have here then a continuous series of deposits at least 

 4000 feet thick, carrying sandstones from top to bottom and 

 interbedded throughout with clay shales, and siliceous shales of 

 the Monterey type, the sandstones more abundant in the lower 

 portion, but a 50-foot stratum at the top, the lower sandstones 

 more or less fossiliferous and showing a fauna similar to the 

 Vaqueros of the central ranges. Thus again we get repetitions 

 of "Monterey shale" and "Vaqueros sandstone" in a way similar 

 to the western Contra Costa County area already described. 



03 U. S. Geol. Surv. Bull. 309, pp. 138-198 (1907). 



54 The correlation table on p. 143 of that bulletin does not agree with 

 the description in the text. 

 " 5 Italics not in original. 



