136 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Seb. 



ter and lignitic matter was found in the cleavage planes of the 

 sandstones. No leaves or fossils of any kind v^ere found. 



While the sandstones greatly predominate at the base they 

 are interbedded with yellow clays and the sands become thinner 

 and the clay bands become thicker higher in the section. Half- 

 way down the mountain the sandstones carry boulders of con- 

 cretionary clay ironstone, some of which are as much as two 

 feet in diameter. Succeeding these beds the clays gradually 

 give way to shales and the lower portion of the mountain was 

 composed of bluish gray shale interstratified with fine-grained 

 yellowish brown sandstone in layers three to six inches in 

 thickness, while the shale beds are as much as a foot thick. 



As there was no Tamasopa limestone observed in the area 

 where we found the Chicontepec beds the relation of the two 

 was undetermined. 



From the strong resemblance of the Chicontepec beds to 

 those of the Eocene at Ramones, Professor Cummins was in- 

 clined to refer them to that horizon. 



It will be noted that while the upper beds are very largely 

 made up of blue shales the basal beds, instead of being lime- 

 stone like the San Juan, are sandstones. 



The same shales and sandstones are well exposed in the hills 

 south of El Xuchil, and numerous seepages of chapapote occur 

 in these blue shales in the vicinity of the basaltic dikes which cut 

 them at many places. Carmelita Ranch lies five miles north of 

 El Xuchil, and a mile to the eastward the bed of an arroyo 

 shows a dike of basaltic material coming up through blue shales 

 which have been hardened on both sides of the basalt. The 

 shale has been impregnated by asphalt, and, away from the 

 dike, carries masses of clay ironstone in banded nodules. At 

 Pedernalis Ranch, which is northwest of Carmelita, a similar 

 bed of asphaltic shale was found, and the surrounding hills 

 were made up of gray and blue shales. At one place the shales 

 showed several thin bands of hard sandstones with fucoid- 

 like impressions. 



The beds, described by De Golyer as succeeding the Tama- 

 sopa southwest of Tuxpam and to which he applies the name of 

 San Felipe Beds, apparently differ considerably from the San 

 Juan (San Felipe of Jeffreys and Huntley) of the Valles 

 region. He says of them : 



