ABSTRACT: Dinosaur National Monument: The World of Dinosaurs in Northeastern Utah
Daniel J. Chure
Between 1909 and 1924, large-scale excavations near Jensen, Utah, produced an unprecedented treasure trove of medium to large vertebrates from the Morrison Formation (Upper Jurassic). The remains of some 400 individuals, belonging to 14 species of dinosaurs, crocodilians, and turtles, were collected, many of which are still the best known specimens of those taxa. In 1915, the area was designated as Dinosaur National Monument. Today, a 150 ft × 50 ft section of the quarry with 1500 bones exposed in situ is protected within a building and is a focus for visitors to the monument.
The bone-producing layer at the main quarry is a conglomeratic sandstone of fluvial origin. This has produced a sample biased toward the larger components of the fauna. Recent work in the monument has focused on distal floodplain and pond deposits in hopes of finding smaller and more fragile components of the fauna. These sites have produced abundant remains of sharks, turtles, crocodilians, lizards, and mammals. Combining data from all sites in the monument yields a more complex picture of the diversity of the Upper Jurassic terrestrial community of the western United States.
AAPG Search and Discovery Article #91002©1990 AAPG Rocky Mountain Section Meeting, Denver, Colorado, September 16-19, 1990