File:Sauropod dinosaur trackway (Morrison Formation, Upper Jurassic; Copper Ridge Dinosaur Tracksite, Grand County, Utah, USA) 17.jpg

English: Sauropod dinosaur footprints in sandstones in the Jurassic of Utah, USA.

This photo shows a series of dinosaur footprints in eastern Utah. The locality is known as the Copper Ridge Dinosaur Tracksite. It was discovered in 1989. Five trackways are present. The most conspicuous (seen here) is a sauropod track that displays a right-hand turn during walking. Individual sauropod footprints have push-up structures. The sauropod was probably Camarasaurus or Apatosaurus or Diplodocus. Sauropods were the largest and most massive of all dinosaurs. They were quadrupedal herbivores with hyperelongated necks and tails.

The site also has theropod dinosaur footprints - a large theropod trackway has been interpreted as a limping Allosaurus. Three small theropod tracks are also present.

The dinosaur tracks are in a fluvial sandstone, interpreted as an ancient sandbar. The rocks here are part of the Morrison Formation, a widespread Upper Jurassic succession consisting of fluvial (river/floodplain) and lacustrine (lake) deposits. It outcrops principally in Colorado, Wyoming, Utah, New Mexico, and Montana.

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From public signage: Welcome to Copper Ridge. Here, you can see the tracks of two different dinosaurs. The larger tracks were probably made by an Allosaurus, while the smaller three toed tracks were made by one of a number of small bipedal carnivorous species.

The tracks preserved here include those of five meat-eating dinosaurs of various sizes and one of a large sauropod dinosaur, a plant-eating animal that likely weighed close to 18 tons. The trackways cross what was, 150 million years ago, a ripplemarked sandbar along a river. The sauropod, possibly Camarasaurus, seems to have made a right turn here. The large theropod that left its tracks to the east may have been an Allosaurus, a hunter capable of traveling up to 30 miles per hour.

The tracks here are preserved at the top of the Salt Wash Member of the Morrison Formation. This landform represents streams and rivers that crossed the area during the Late Jurassic. The sandbar on which these dinosaurs walked may have been bordered by plants such as ferns, cycads, conifers, and ginkgo trees.

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Stratigraphy: top of the Salt Wash Member, Morrison Formation, Upper Jurassic

Locality: Copper Ridge Dinosaur Tracksite, Copper Ridge, east of Little Valley & east of Rt. 191 (turnoff from Rt. 191 is 8.5 miles south of Interstate-70), south-southeast of Crescent Junction & north-northwest of Moab, Grand County, eastern Utah, USA (38° 49’ 54.06” North latitude, 109° 45’ 43.35” West longitude)