114 GUIDEBOOK OF THE WESTEEN UNITED STATES* 



Maria oil field in view on its flanks. Mount Solomon, a flat-topped, 

 buttelike peak, composed of Tertiary rocks, is visible just to the left 

 (east) of the oil field. It is the culminating point of Graciosa Ridge. 

 Southwest of the Santa Maria bridge the drifting sands encroach to 

 an elevation of 1,000 feet on the flanks of Sulphur Ridge. Tliis 

 encroaching sand rising so high on the mountains is one of the peculiar 

 characteristics of this part of the coast. 



■blown 



:rain passes through a reg 

 as far asBromela (bro-may 



is a prominent ridge of sand dunes advancing upon rich farms. 

 Farther north, between Bromela and Callender, the dunes have 

 advanced far inland across the railroad, and the company has an 

 expensive task in maintaining the roadway open. Between CaUender 



and Oceano (o-say'ah-no) the advance is less rapid and lagoons 



the sand. Just beyond Oceano, at the mouth 

 ^Spanish for water cresses), Pismo Creek barely 



behind 



breaks tln-ough the barrier beach it has followed for 2 miles from Pismo. 

 On the way up Pismo Creek beyond Pismo (see sheet 4a, p. 120) 



the first rocks to be seen on the east are those of the 

 rismo. Santa Margarita formation (Miocene), the equiva- 



Eievation2ofeet. i^j^^^ ^f j-]^^ lowcr part of the Fernando formation 



. Los Angeles 212 miles. * , , ^ 



farther south. South of Edna the creek crosses a 



large area of these rocks, which in places are heavily charged with 

 asphalt. 



just 



are bold bluff exposures of asphalt-impregnated sandstones of the 



Pismo formation, which is probably of the same age 

 . "^* as the Santa Margarita formation. They dip south 



STi"if2^^^^^ ^* moderately low angles and are underlain by more 



steeply dipping shale beds of the Monterey group. 



mi 



a of asphalt as a by-product from the refining of oil has for the 

 ^ent rendered them of no value. 



5ome oil wells have been drilled on the west side of the track south 

 Edna. One or two of these wells encountered oil in commercial 



• . « 



quantities, but tliey have never been operated continuously, owing 

 to mechanical difficulties caused by the tliickness of the oil. The 

 dark-colored asphaltic rock is cavernous in places and is eroded into 

 grotesque forms. East of Edna are some well-developed stream 

 terraces . 



T 



At Edna the railroad enters San Luis Valley, which extends 

 northwestward for 20 miles. On the northeast the valley is bounded 

 by the Santa Lucia Range and on the southwest by the San Luis 

 Range. At the northwest end it opens to the ocean. This valley, 

 unhke most vaUevs in the Coast Ranges, has no stream flowing 

 lengthwise through it. Pismo and San Luis creeks, which drain 



