Fossils

The Cleveland-Delfs quarry revealed a Late Jurassic environment that was home to more than just dinosaurs. The fossils show us that the area was a wet environment, probably a lake, pond, or river, that supported a diverse population of reptiles.

Sauropod Dinosaur

Haplocanthosaurus delfsi

Haplocanthosaurus is classed as a primitive sauropod because the spines on the vertebrae are not forked as they are in all the other Garden Park sauropods. According to Kenneth Carpenter, in The Dinosaurs of Marsh and Cope, Haplocanthosaurus is limited to the lower member of the Morrison Formation and was, more than likely, replaced by Camarasaurus another sauropod that competed with Haplocanthosaurus for the same resources, such as food. No skulls of Haplocanthosaurus exist, so we don’t know exactly what the head looked like, but we can assume it was a plant eater because other sauropods only have teeth suitable for a diet of plants.

Haplocanthosaurus delfsi (H. delfsi) is the largest specimen of Haplocanthosaurus and has only been found in Garden Park. It is about seventy two feet long and fourteen feet tall at the hips, and weighed about twenty tons. Another species found at Garden Park, Haplocanthosaurus priscus, is estimated to be only 45 feet long and nine feet tall at the hips, so this is almost half the size of H. delfsi. Haplocanthosaurus has been found in other locations in Colorado and Wyoming, but the skeleton found by Edwin Delfs and his crew is the only specimen complete enough for public display. It is currently mounted at the Cleveland Museum of Natural History and is affectionately known as “Happy.”¹

Other Reptiles

Crocodile: Eutretauranosuchus delfsi

Eutretauranosuchus is a small, rare goniopholidid crocodilian from the Jurassic period. The crocodile was a semi-aquatic carnivore that would spend most of the time in rivers and ponds or sunning itself on the shores. The diet of this crocodile was mainly fish and small to medium - sized terrestrial vertebrates. Crocodiles are some of the most common vertebrate fossils from the Morrison Formation -especially their shed teeth and scutes – and several species are known and described from Garden Park, including Goniopholis felchi, Goniopholis lucasi, and Eutretauranosuchus delfsi (E. delfsi).

Scientists often use teeth and scutes to determine the species of fossil remains, but in the case of Eutretauranosuchus delfsi determination of the species was based on the skull, which had been preserved along with a partial skeleton. Eutretauranosuchus delfsi was considered a new species based on several unique features of the skull that differed from the type specimen of Goniopholis from England. The specimen found by Delfs was only 5’8” long and was thought to have weighed about 90lbs (40kg). Because of the size and the presence of un-fused vertebrae, the specimen is considered to be a juvenile.²

 Turtle: Glyptops plicatulus

Turtle shell fragments are common finds in the Morrison Formation. In Garden Park, Glyptops plicatulus shell fragments are common throughout the formation. This is the turtle found at the Cleveland-Delfs quarry. Turtle shells have features that scientists use to determine the species, and in the case of Glyptops plicatulus these features used are raised ridges and tubercles. Like their modern counterparts, Late Jurassic freshwater turtles lived in and near ponds, lakes, and rivers and their fossils are commonly found in wet environment quarries in the Morrison Formation.³

Endnotes

¹Kenneth Carpenter, The Dinosaurs of Marsh and Cope: The Jurassic Dinosaurs of Garden Park (Garden Park Paleontology Society:Cañon City, n.d.)

²For discussions on the crocodile see: C Mook, “Preliminary description of a new goniopholid crocodilian,” Kirtlandia 2 (1967):1–10; John Foster, Jurassic West:The Dinosaurs of the Morrison Formation and Their World (Bloomington:Indiana University Press, 2007), 152; Kenneth Carpenter, “Vertebrate Biostratigraphy of the Morrison Formation near Cañon City, Colorado,” Modern Geology 23 (1998): 411- 412.

³For information on the turtle see: John Foster, Jurassic West: The Dinosaurs of the Morrison Formation and Their World (Bloomington:Indiana University Press, 2007), 152; Kenneth Carpenter, “Vertebrate Biostratigraphy of the Morrison Formation near Cañon City, Colorado,” Modern Geology 23 (1998): 411- 412.