During the construction of the Union Pacific Railroad in the 1860s, workmen blasting a cut through Green River shales, about 2 miles west of Green River, Wyoming, came upon remains of well-preserved fish. Hayden (1871:742) first mentions this cut as "Petrified Fish Cut." Many of the fish from this cut were given to Cope who described them in Hayden’s (1871) report. Insects, plants, and a bird feather were also obtained from "Petrified Fish Cut" at this time.
Sometime in the 1870s the first fish were obtained from Fossil Butte itself. Cope (1877, 1878) described fish from the Green River Formation which may be from Fossil Butte. His locality is "nearer the mainline of Wasatch Mountains" (Cope 1877:807). This may be Fossil Butte. His 1878 locality information is just as poor. He does mention a specimen of Priscacara peali given to him by A. C. Peale. Since it was Peale who first wrote about Fossil Butte, the specimen may have come from the butte.
Peale (1879) first mentioned the quarrying of fish at Fossil Butte, but he had no specific date as to the discovery of the butte or the beginning of quarrying of fish.
Cope (1884) published two large volumes about the Tertiary vertebrates of the West. Here he mentioned three fossil localities for his Green River Fish: "Petrified Fish Cut," "The Mouth of Labarge Creek," and "Twin Creek." Twin Creek is now known as the Fossil Butte site.
Since that time, the quarries at Fossil Butte have been extensively worked, mostly by commercial collectors.
The fish from Fossil Butte form an unusual array of genera (Table 1) unlike any now found living together. Included in the assemblage are forms usually found in marine waters and tropical, fresh-water fish (Schaeffer and Mangus 1965).
TABLE 1. Simplified classification of fish from Fossil Basin.
Elasmobranchii Trygonidae Xiphotrygon (sting ray) Chondrostei Polyodontidae Polyodon (paddle fish) Holostei Lepisosteidae Lepisosteus (gar) Amiidae Amia (bowfin) Isospondyli Osteoglossidae Phareodus Gonorhynchidae Notogoneus (sand fish) Clupeidae Diplomystus (herrings, shad) Knightia Ostariophysi Siluridae Ameiurus (catfish) Xenarchi Aphredoderidae (pirate perches) Erismatopterus Asineopidae Asineops Acanthoptergii Percidae Mioplosus (perches) Serronidae Priscacara
More than 40 species of fish have been described from the Green River shales, but authorities do not agree on how many of these are valid. Because of this, only super specific groups will be considered in the following discussion.
