Lawson. 



Post-Pliocene Diastrophism. 



155 



the delta lies is a valley of erosion (probably along a fault line), ante- 

 dating in its origin the Pliocene deposits, and following the post- 

 Miocene uplift. 



The Santa Maria Valley. — This valley has not been visited by 

 the writer, but some very explicit and suggestive information con- 

 cerning it has been placed on record by Antisell.* His statements 

 are here quoted: "The Santa Maria or Cuyama Valley differs from 

 any other observed in not having a true outlet. On the south it is 

 shut up by the San Emilio mountain region; on the east, by the low 

 porphyritic feldspar range running into that mountain also; on the 

 north it is occluded by the cross ranges given off from the Santa 

 Lucia, and by this range on its west, throughout the whole length ; 

 it is completely shut in, except at the point where the river canons 

 through the narrow gorges of the Santa Lucia. This is a channel 

 which the river itself has partly cut for itself and can scarcely be 

 called a natural outlet of a plain. The slope of the base of the plain 

 is to the north by west, and would naturally pour its waters into the 

 small valleys of San Jose and Santa Margarita were it not prevented 

 by the serpentine ridges crossing it at the head of these locali- 

 ties. The observer, first casting his eye over the extended plain, 

 widening towards the south by the recession of the mountain ranges, 

 would at once set it down as the basin of a great arm of the sea, 

 which ran up towards the north, and that the natural debouche was 

 towards the southeast, or opening into Tulare plain. This may have 

 been the case once; but at such time Tulare plain itself was not so 

 elevated or cut off from communication with the desert east as at 

 present. The elevation of Tulare and Santa Maria were coeval. 

 The sandstones and gypseous beds found northwest of the Canada 

 Uvas may be traced round the side of the porphyry domes into 

 Cuyama Valley as a continuous series, elevated by the same local 

 action ; and as the Estero plain lies between Tulare and Santa Maria 

 Valleys, upon the crests or in a trough between the porphyry ranges, 

 the continuation of the San Jose Range, which also stretches under 

 Panza and Cariso, that plain (Estro) belongs to the same age, and 

 the San Jose Range, by its elevation, separated for the first time the 

 previously connected plains of Cuyama and Tulare Valley. 



* Pacific Railway Reports, Vol. VII, 1857, Part II, pp. 55-57. 



