Geol— Vol. II.] ANDERSON— CRETACEOUS DEPOSITS. 5 1 



than it was one hundred and fifty miles north, in 

 Tehama County; while if the Horsetown and a part of 

 the Knoxville beds are really lacking, there must have been 

 a local uplift in the Mount Diablo region which did not 

 involve the Coast Ranges farther north." The Chico beds 

 are here the Upper Chico and much of the five thousand 

 feet of strata intervening between this and the Aucel/a beds 

 must evidently belong to the Chico group, since on the 

 south side of the mountain the Lower Chico occurs. One 

 is forced, then, to accept Mr. Stanton's second alternative, 

 with the amendment, however, that the uplift, while local, 

 was only a local accentuation of a disturbing influence much 

 more general throughout the Coast region. 



It will be interesting to remember here the cases of un- 

 conformity discovered by Fairbanks (1895, p. 426, etc.) 

 between Chico and Knoxville beds in San Luis Obispo 

 County, in reference to which he says: "The Knoxville 

 (Paskenta) is bordered on the west by a great dike of ser- 

 pentine, while on the east a nearly hidden axis belonging to 

 the Golden Gate (Franciscan) series projects through it in 

 numerous places. The Knoxville presents a very much 

 disturbed condition, partly due to the dikes of serpentine. 

 The Chico, consisting almost wholly of heavy bedded sand- 

 stone, rises on the eastern slope, overlapping the Knoxville 

 shales and capping portions of the first line of hills." 

 Points at which this unconformity is particularly clear he 

 has discussed more in detail. One was found upon the 

 Eagle Ranch, west of Santa Margarita, and another a 

 few miles to the northwest, where almost undisturbed 

 Chico sandstones rest upon highly tilted Knoxville shales 

 with Aticella fiochi. Concerning this region Dr. Fair- 

 banks (1898, p. 560) says in a later paper, speaking of the 

 Chico: " Fossils are not abundant but they were found 

 in sufficient numbers in the Santa Lucia Mountains to 

 demonstrate the age of the formation. In the latter locality 

 the sandstone terminates downward in a conglomerate which 

 is in places one hundred feet thick, resting either upon the 

 Knoxville shales or the Golden Gate series. The relation 



