502 EMMONS AND MERRILL SKETCH OF LOWER CALIFORNIA. 



b}'' Mr A. D. Foote), eight miles north of Bluff point, the following forms 

 were identified by Mr T. W. Stanton : 



Cardita planicostata, Lam. 

 Leda gabbi, Conrad. 

 Urosyca caudata, Gabb. 

 Nucula, sp. undetermined. 

 Pectunctdus, sp. undetermined. 



Telllna, sp. undetermined. 

 TarriteUa, sp. undetermined. 

 Dentalium, sp. undetermined. 

 Crussatella, sp. undetermined. 



and are considered by hira to belong undoubtedly to the Tejon-Eocene. 



The beds carrying Chico and Tejon fossils were not observed in direct 

 superposition, but from the negative evidence that no decided uncon- 

 formities were detected at any of the points examined, it is assumed that 

 the two series are conformable, or that in any case no considerable dis- 

 turbance of the strata took place between the times of their respective 

 depositions. 



The great mesa or plateau, 15 miles long and 6 to 8 miles in Avidth, 

 which extends from the valley of Santa Caterina northward beyond San 

 Carlos, has an elevation of from 1,800 to 2,000 feet, being somewhat 

 higher at the northern end. The greater part of its surface is apparently 

 capped by basalt flows, which have protected it from erosion. From a 

 distance can be distinguished conical points rising above the level of the 

 mesa, known as the " Sombrero,'' the " Hat," etcetera, which resemble 

 recent craters in general form. At one point on the coast fragments of 

 the basalt, cemented together by crystalline calcite, have fallen to the 

 foot of the bluff in huge masses and form a projecting point on the coast- 

 line. 



For about a mile beyond Sandstone point the beach is covered with 

 beautifully rounded pebbles of porphyries and a great variety of hard 

 rocks, mostly older eruptives, whose material must have come down a 

 ravine which drains the western face of the plateau and descends very 

 rapidly from its summit. As no such pebbles were observed in the 

 Chico or Tejon series, nor on the beaches to the south where no upper 

 beds remain, it is thought probable that the mesa sandstones, which are 

 characterized by an abundance of eruptive material, may form the upper 

 portion of this plateau. 



Northward from San Carlos, as seen from the ocean or from com- 

 manding points of view in the interior, the same character of beds, with 

 their characteristic bad-land topography, extend northward to the Ro- 

 sario ravine. 



The hamlet of Rosario is situated a few miles from the sea, in this 

 ravine or canyon, which extends inland for some 10 or 15 miles with 

 very gradual rise of its beds, and carries a small stream of running water 

 that in dry seasons sinks below the surface sands. The cliffs of the 



