Campanian Trachyscaphites spiniger ammonite fauna in north-east Texas

Journal article

A horizon 46 m above the base of the Ozan Formation in the North Sulphur River north-west of Ladonia in Fannin County, Texas, yielded an ammonite fauna which includes Trachyscaphites spiniger spiniger (Schluter, 1872). The presence of T. spiniger spiniger, previously known only from western Europe and the USSR, dates the assemblage as early but not earliest late Campanian in a north-west European sense, while stratigraphic relationships to other Gulf Coast Campanian faunas suggest it to be younger than the early Campanian zone of Scaphites hippocrepis III and older than the middle Campanian zone of Baculites mclearni of the US Western Interior. The Western Interior lower-middle Campanian boundary and the European lower-upper Campanian boundary are approximately coincident; this level can be dated at 80 Ma approximately on the basis of radiometric dates from Western Interior bentonites. -from Authors

Authors: Cobban, W; Kennedy, W

• Journal: Palaeontology
• Volume: 35
• Issue: 1
• Pages: 63-93
• Publication date: 1992-01-01
• ISSN: 0031-0239
• Language: English