292 University of California Publications in Geology ["Vol. 12 



top soil and the washes later revealed further interesting material. 

 Fossils have been found in place in the following sediments : 



1. Nodular, indurated, sandy clays: In tracing the source of 

 fragments of bone and digging within the top soil small pockets have 

 been located containing nodular sandy clay rock, reddish tinged on 

 fracture, and holding associated skeletal remains. The rocks lay in a 

 stratum of fine sandy, micaceous clay, which farther down contained 

 less clay and more sand, and at slightly lower levels passed into grayer 

 and coarser sand. At one locality (3242) three such pockets occurred 

 within a radius of twenty feet, containing equine limb bones that had 

 apparently belonged to the same individual. The manner of occur- 

 rence, and the fact that certain separated nodules contained parts of 

 the same bones, the broken silicified edges of the bones matching when 

 brought together, evidence that considerable movement has occurred 

 in the deposit since the time of deposition and nodularization. 



2. Thick deposits of black clay : Within the south-central part of 

 the Bautista district, at twenty-five hundred feet elevation, are con- 

 siderable northeast-dipping deposits of lustrous black, micaceous clays 

 alternating with fine sands. Similar beds have been noted dipping 

 to the southwest in a ravine eight hundred feet lower down. At one 

 place at the higher elevation these clays were found to contain many 

 bone fragments, and here (locality .3243) much of the most representa- 

 tive Bautista material was obtained. The operation was carried on in 

 a four-foot stratum that was interbedded between layers of coarse, 

 gray sand. Above the latter was another layer of the clay a foot in 

 thickness, and this was overlain by coarse, yellowish sand, which higher 

 up became graj^er and was mixed with quartz pebbles. The fossils 

 though comparatively plentiful were soft, and were minutely broken 

 from the gradual movement evidenced in the network of cracks that 

 ran throughout the entire deposit. 



3. Fine and coarse, non-indurated sands : Fossils were found to a 

 somewhat le&s extent in the non-indurated sand beneath these clays. 

 Exposures of micaceous, fine, greenish sand, rather frequent through- 

 out the southwestern portions of the Bautista, have also yielded con- 

 siderable material, especially in the neighborhood of calcareous ledges. 

 The original equine jaw fragment was found by Mr. Blackburn in such 

 a formation (locality 3240). 



4. Exceptionally, in fine, brown-gray, micaceous sandstone : A piece 

 of this rock picked up at the mouth of one of the canons yielded a 

 well preserved fragment of the mandible and teeth of a small artio- 

 dactyl. 



