GEOLOGY OF THE SALINAS VALLEY 



335 



This seemed to be the case near the southernmost point 

 of the Miocene area shown on the accompanying geological 

 sketch map. Here the gravels and sands rest on the sandstones 

 and shales and have apparently the same dip and strike. For 

 the most part, however, along the parting between the Pliocene 

 and the Miocene, there is such a marked difference in the dip of 

 the two series on either side of the contact, as to make almost 

 certain an erosion line between them. 



The Miocene shales and sandstones are much contorted, and 



>\ ■•■<■■> 



5ano*5 + one 



Fossi/i fe tout 

 5 andsio ne 



Abou+ 1/4 mile- 



|o344 c 



I 



C/ai 



ngzg Lignite in Cloy ±gg 



Gypsu/n in Clay 

 Fig. 5. — Terrace beds exposed in a railway cut three miles northwest of Bradley. 



are characterized by steep dips, sometimes vertical. The Plio- 

 cene sands and gravels 1 have much gentler dips and are also 

 persistently characterized by having a capping of soft limy sand- 

 stone. 



The ranges of hills lying between the Nacimiento and San 

 Antonio creeks, and the San Antonio Creek and the Salinas 

 River are made up almost entirely of Miocene sandstones and 

 shales ; while the valleys of the Nacimiento and San Antonio 

 are filled with the Pliocene sands and gravels. 



There is much granite and gneiss in the region drained by the 

 head waters of the Arroyo Seco, the San Antonio, and the Naci- 

 miento, as the beds of these streams are filled with pebbles and 

 bowlders made up of these rocks. 



"The age of this Pliocene area was determined by fossils collected in a railway 

 cut three miles northwest of Bradley. The Miocene fossils are from shale beds out- 

 cropping on the southwest bank of the Salinas River at Wunpost. They were all iden- 

 tified by Mr. Ralph Arnold. 



