WATER-BEARING FORMATIONS OF SALINAS VALLEY. 



209 



N.W. 



S.E. 



older rock. The ages of these Pliocene and Miocene beds were fixed from fossils 

 found in them, which were identified by Mr. Ralph Arnold, of Stanford University. 

 The Pliocene fossils were found in sandstone about '20 miles southeast of Monterey' 

 City, in sec. 20, T. 6 S., R. 3 E., M. D. M. The beds in which they occur are appar- 

 ently the same as those east of Kings City. The Miocene fossils were from shale 

 beds outcropping on the west side of the Salinas River at Wunpost. 



In the southern part of the countj- there have been at least two general elevations 

 of the land surface, for the Pliocene gravels forming the large terrace are to a great 

 extent composed of shale pebbles, and these same beds have been tilted and are con- 

 formable with beds of shale. 



The partings V>etween the rock in place and the gravels and other alluvial material 

 were traced from a point about 2^ miles east of St. Joseph's Colony, in sec. 18, 

 T. 15 S. , R. E. , in a general southeasterly direction, to the southwest corner of 

 T. 18 S., R. 8 E., and from Lonoak on the San Lorenzo River in a general south- 

 easterly direction through the Peach Tree, Slacks Canyon, and Cholame Valley 

 country to Parkfield. They were also 

 traced from Pleyto, in T. 2-lS., R. 9 E., 

 around the San Antonio Valley, and to 

 some extent in the Nacimiento River 

 country. Also from the San Luis 

 Obispo Countj' line the partings were 

 traced around Hames Valley to Wun- 

 post Station, thence in a general north- 

 westerly direction to a point about 2 

 miles south of Spreckels' beet-sugar 

 factoiy, thence southward to sec. 21, 

 T. 16 S., R. 3 E. 



Beginning at about the southwest ^"'- e-Outcrop of beds in terrace immediately south of head 

 " *' , _ . , of Salinas Valley Water Company's irrigating ditch on the 



corner of 1 . 18 S. , R. 8 E. , is the terrace san Lorenzo River. 



or upland, formed of the marine Plio- 

 cene beds already mentioned. At the head of the Salinas Valley Water Company's 

 irrigating ditch on the San Lorenzo River the terrace is formed of beds of coarse 

 and fine sandstone and flinty conglomerate. (Fig. 6.) 



The fact that these beds are hardened into sandstones and conglomerate at this 

 and some other points led to the supposition that the line between the terrace and 

 the valley lowland marked the easternmost limit of the water-bearing gravels, and 

 consequently this line was traced. Data subsequentlj' collected seemed to show, how- 

 ever, that the lowest beds of this terrace, which are for the most part porous sands 

 and gravels, extend under the Salinas Valley. It therefore seems certain that the 

 terrace area is lai"gely tributary to the underground water supply, and the eastern 

 limit of this area was consequently ti-aced out. 



From the contact east of St. Josephs Colony to about Riyer bank the rock in 

 place is granite, mica schist, and gneiss, and the alluvial material which laps upon 

 these rocks is a granite soil containing angular fragments of granite and schist. 

 Occasionally, slightly rounded fragments, looking as though they had been water- 



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