Jackson Group of Formations in Texas with Notes on Frio and Vicksburg

Abstract

ABSTRACT The Jackson formation of Texas is raised to the rank of a group, and a new nomenclature is given for the various formations and members of this group. The three formations of the Jackson, namely, Whitsett, McElroy, and Caddell, are subdivided into members. Sections of the Jackson from Atascosa County to Sabine County are given, showing the variation in the sections, the unconformities, and the overlaps. Subsurface sections are given to show the persistence of these formations across Texas, to show the relationship of the surface to the subsurface, and to show the unconformities at the top of the Jackson. A section is given to establish the stratigraphic position of the Frio and to show the presence of the Vicksburg in Texas.