Pachydiscus (Pachydiscus) paulsoni (Young, 1963)

Remarks

• Collector:    Bill Jolley

• Formation:  Taylor Group, Anacacho Limestone

• Location:     Medina County, TX

Remarks

• Collector:    Dan Woehr

• Formation:  Taylor Group, Pecan Gap Chalk

• Location:     Bexar County, TX

General Info

Synonyms (older names and misidentifications in the literature)

• 1963 Parapuzosia paulsoni Young
• 1992 Pachydiscus (Pachydiscus) paulsoni (Young); Cobban and Kennedy

Stratigraphic Occurrence

• Upper Austin Group, Dessau Formation of Central Texas
• Upper Austin Group, upper Gober Formation of North Texas
• Lower Taylor Group, lower Anacacho Formation of South Texas
• Lower Taylor Group, Ozan Formation of North Texas

Age

• Pachydiscus (P.) paulsoni (Young) occurs in the Submortoniceras tequesquitensis (Young) zone, according to Young (see ref below), which would place it in earliest Campanian time (~83 mya).   However, it’s occurrence in the upper Gober and lower Anacacho Formations suggest that it ranges into the Menabites (Delawarella) delawarensis (Morton) zone as well (~81 mya, give or take), also lower Campanian.  The upper limit of its range is indicated by its conspicuous absence (at least not reported) in the Pecan Gap Chalk (Baculites mclearni Landes Zone, middle Campanian).

Geographic Occurrence (not an all-inclusive list)

• Fannin County, TX
• Lamar County, TX
• Medina County, TX
• Travis County, TX

Remarks

For identification and descriptions, see:

• Cobban, W. A.; Kennedy, W. J. 1992. Campanian Ammonites From the Upper Gober Chalk of Lamar County, TX. Journal of Paleontology 66 (3), 440–454
• Young, K. 1963. Upper Cretaceous Ammonites From the Gulf Coast of the United States. University of Texas Publication 6304.