Formation · Paleogene
Stone City Formation (Whiskey Bridge)
Eocene unit, Texas
The Stone City Formation at Whiskey Bridge on the Brazos River is Texas's best-known Eocene shell bed, yielding hundreds of species of small, perfectly preserved gastropods and bivalves (Turritella, Venericardia, Athleta, Conus), small shark teeth and occasional crabs. It is a public, legal and free site, ideal for micro-shell collectors. Aragonite shells are chalky and fragile once dry; sieve, bag damp and consolidate at home.
| Country | United States |
|---|---|
| Region | Texas |
| Age | Lutetian, Eocene |
| Age range | ~43–40 Ma |
| Group | Claiborne Group |
| Macrostrat rank | Fm· Macrostrat |
| Macrostrat age | 56–33.9 Ma· Macrostrat |
| PBDB collections | 60 collections, 1537 occurrences· Paleobiology Database |
Collecting and legality
Whiskey Bridge is a Texas DOT highway right-of-way on the Brazos River (SH 21 west of Bryan) and has been a public collecting site for decades; collect from the bluff face and the river bank, watch for traffic and high water. Finds are the collector's own.
Lithology and setting
Glauconitic, fossiliferous marine sand and clay of the middle Eocene Claiborne Group, with shells preserved in original aragonite.
Commonly recorded taxa (PBDB)
Genera most often recorded from this unit in the Paleobiology Database (first 200 occurrences): Architectonica (8), Athleta (6), Buccitriton (6), Cochlespira (6), Trigonostoma (5), Ancilla (4), Bonellitia (4), Brazosiella (4), Ficus (4), Pyramidella (4), Turritella (4), Closia (Bullata) (3), Cochlespirella (3), Eulima (3), Gegania (3).
Source: Paleobiology Database
Collecting rules
Elsewhere
Cite this article
Stratum Study. "Stone City Formation (Whiskey Bridge)" (Formation). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/formations/stone-city-formation-whiskey-bridge. Accessed 2026-09-20.
@misc{stratum-stone-city-formation-whiskey-bridge,
title = {Stone City Formation (Whiskey Bridge)},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/formations/stone-city-formation-whiskey-bridge}},
year = {2026},
note = {Formation article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, macrostrat, pbdb, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.