590 INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



In the State of Puebla, at Zapotitlan and San Juan Raya, the terrane consists 

 of gray argillaceous rocks, marly gypsiferous yellow shales, calcareous green 

 sandstones, marly green sandstones, and varicolored shales. 



In the State of Vera Cruz, at Necoxtla, occur argillaceous micaceous reddish 

 gray or black shales, with beds of limestone in the upper part but without fossils. 



In San Luis Potosi, at Catorce, there are in the upper part shales and marly 

 sandstones and compact limestones. 



In the State of Tamaulipas, at Miquihuana, there are beds of sandy shales and 

 limestones which rest upon sand with pebbles of quartz but which are unconform- 

 able upon the older Mesozoic strata. According to Hill they closely resemble the 

 beds of the Trinity group of Texas but have a different fauna. Felix and Lenk 

 believe that these beds represent the littoral facies of their Monopleura beds of 

 Tehuacan. 



In the northern part of the State of Zacatecas (at Mazapil, Santa Rosa, Concep- 

 cion del Oro, and Canutillo) the Eo-Cretaceous begins with marl and limestone. 

 Above these come bluish limestones and other limestones with large concretions of 

 chert, having a thickness of 400 or 500 meters but poor in fossils, and yellowish 

 marls containing many forms. These last-named beds may serve as the plane of 

 separation between the Eo-Cretaceous and the " Meso-Cretaceous. " 



Occurrences of "Meso-Cretaceous" strata are specifically listed by Aguilera 

 from the following localities in several States : 



In Chiapas and Guatemala there are limestones and dolomites, in general in 

 thick beds but in some places occurring in thin beds. Some of the layers present a 

 brecciated structure. In the lower part the limestones include concretions -and 

 nodules of chert; in the upper part they inclose intercalations of dolomite. These 

 limestones form an extensive belt which runs through the center of the State of 

 Chiapas, passes on to Guatemala, and ends in the Gulf of Honduras. 



In the State of Michoacan, at Coalcoman, are compact black and gray lime- 

 stones. At Aguililla occur compact gray and blackish limestones with chert, but 

 without fossils. At Huetamo are compact limestones and calcareous shales. 



In the State of Mexico, at Zumpahuacan, in the Sierra de San Gaspar, are com- 

 pact gray yellowish-white limestones. In Morelos the horizon is represented at 

 Ayala and Yontepec. 



In Jalisco fossils of the "Meso-Cretaceous" have been obtained at Saistra, Sierra 

 de Tapalpa, and at the hacienda of Huilcalapa, Canton de Zapotitlan. 



In the State of Vera Cruz the limestones of Orizaba may be divided, from 

 above downward, into the Escamela limestones, which are gray and occur in thick 

 beds with a facies of Rudistes and Chamides, and the Maltrata limestones, with 

 blackish cherts and without fossils. 



In the State of Queretaro, at Cadereyta, occur compact gray fetid limestones, 

 limestones with chert, and calcareous and argillaceous shales. 



In the State of Hidalgo, at Zimapan, are compact gray fetid limestones with 

 calcareous shales. 



In the State of Zacatecas, at Mazapil, Santa Rosa, Concepcion del Oro, Fres- 

 nillo, Comacho, and Noria de Angeles, occurs a pelagic facies. It consists of lime- 



