Vol. VIII] DUMBLE— GEOLOGY TAMPICO EMBAYMENT AREA 117 



and the overlying shales and sandstones, which extend from 

 near Victoria to the zone embraced between Valles and Taninul, 

 to the Neo-Cretaceous. He describes these beds in the vicinity 

 of Valles as shales, marls and occasional slates with intercalated 

 limestones and sandstones with calcareous cement and says 

 they are unconformable with the massive limestone. With 

 these he also includes the interbedded limestones and sand- 

 stones occurring south and southwest of Tantoyuca. 



The yellow nummulitic rocks of the San Jose de las Rusias 

 range he refers to the Eogene, but considers all of the yellow 

 argillaceous shales, marls, and calcareous beds south of the 

 Tamaulipas range as Neogene and equivalent to the beds at 

 Tuxpam and Papantla. He suggests the name Papantla for 

 these beds. He includes in these Neogene beds the argillaceous 

 shales east of Las Palmas and Tamuin which form the greater 

 part of the Mendez of Jeffreys. 



The Neogene to the south of the Panuco River, as described 

 by Villarello, comprises yellowish fossiliferous calcareous 

 rocks, such as are found outcropping in the neighborhood of 

 Papantla, Coazintla and elsewhere, overlain by sandstones, 

 bluish gray shales and slaty marls and reddish clays. These 

 Neogene deposits rest upon interbedded limestones and sand- 

 stones similar to those near Tantoyuca and are overlain in 

 places by Quaternary sediments. 



These Neogene beds are broken and in places overlain by 

 basaltic rocks and tuffs. 



In 1910 Engerrand and Urbina of the Mexican Geological 

 Commission made a preliminary survey of the Yucatan penin- 

 sula. They record Miocene fossils from Tizimin*, but regard 

 all others as Pliocene or Pleistocene. 



Bose, in Bulletin 20 of the Mexican Geological Commission, 

 reports on the geology of Chiapas and Tabasco. No Cre- 

 taceous was observed later than the rudistes limestone (Tama- 

 sopa?). Extensive deposits of shales, clays, sandstones and 

 lirnestones were found carrying a fauna composed almost alto- 

 gether of nummulites and orbitoides. These he refers to the 

 Eocene. Overlying them, he finds a series of dark shales, clays, 

 and limestones which he describes under the name of the Semi- 

 jovel division. He states that this division may embrace beds 

 of both Oligocene and Miocene age, but that the greater part 



• Bui. Mex. Geol. Soc, Vol. VI., p. 119. 



