Abstract

Foraminifera were studied at the generic and familial level from 62 samples from the conformable (north of Dallas) and unconformable (south of Dallas) sequences of strata at the lithologic contact between the Austin and Taylor Groups. The combined Austin and Taylor fauna consists of 25 families, 49 genera, an average planktonic-benthonic ratio of 4:1, an arenaceous component of about 10 percent, and a total of 43 benthonic genera of which only 6 or 8 are common. Depth of deposition ranging from 200 to 1,700 feet is suggested by comparison of the overall faunal characteristics with those of the present-day Gulf of Mexico. Predominance of Guembelina s. l. over Globigerina s. l. in the definite Austin Chalk samples, and the reverse relationship in the definite Taylor Marl samples, is considered stratigraphically significant.

You do not currently have access to this article.