Bol. Soc. Geol. Mexicana, Tomo XLVII. No. 1. 1986

Coalcomána ramosa (Boehm) (Bivalvia-hippuritacea) del Albiano Temprano del Cerro de Tuxpan, Jalisco

Gloria Alencáster*, ]erjes Pantoja Alor*

*Instituto de Geología, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, D. F.


Coalcomána ramosa (Boehm) is a caprinid rudist very widely distributed in Mexico, Texas and the Caribbean región. It is an index fossil for the Early Albian, and generally is forming bioestromes or bioherms. In spite of its great stratigraphic and paleoecologic value it is not a well known species. In this paper are described and illustrated specimens proceeding from the Hornos Viejos section, which is located in the southern part of the Cerro de Tuxpan, Jailsco. A review of previous studies on the species includes a consideration of the modifications which have been made regarding its geologic age. Also it is discussed the geology of the Cerro de Tuxpan and the stratigraphy of the Hornos Viejos section.