Pg. 348-356. Austin stage. Used here as a provincial time-rock term, as a major division of the Gulf series, to include all strata in Atlantic and Gulf coastal province of North America and adjacent areas which by one means or another can be reasonably demonstrated to be equivalent to the type Austin chalk and its typical subdivisions. If future study discloses that this usage results in overlapping time-rock units, then limit or limits of the units involved should be adjusted to take care of the discrepancy. From place to place upper and lower boundaries of Austin have been mapped as unconformable. Elsewhere passage from underlying beds of Eagle Ford age (stage) takes place without discernible break. Similar relationships are known for passage from Austinian to overlying Tayloran strata. Late Cretaceous (Coniacian to Santonian).

Source: US geologic names lexicon (USGS Bull. 1350, p. 36-37).

Interpretation of preliminary paleomagnetic (a.f. demagnetized) and biostratigraphic data from Upper Cretaceous deposits in southwest AR and northeast TX (Arkla basin and Ouachita tectonic belt province) is presented. It is concluded that the boundary between the Austinian and Tayloran provincial stages approximates the boundary between the Gubbio (Italy) reversed polarity zone A (early Campanian) and the Gubbio normal polarity zone B+ (Campanian to early Maestrichtian).

Source: GNU records (USGS DDS-6; Denver GNULEX).