Gateway to the Paleobiology Database
north end, Black Ridge tracksite (Jurassic of the United States)

Also known as Colorado National Monument

Where: Mesa County, Colorado (39.1° N, 108.8° W: paleocoordinates 34.4° N, 54.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Salt Wash Member (Morrison Formation), Kimmeridgian (155.7 - 150.8 Ma)

• Tracks occur within the middle shaly unit of the Salt Wash Member.

• group of beds-level stratigraphic resolution

Environment/lithology: "channel"; sandstone and mudstone

• "The tracks appear to be associated with a sedimentary facies in which recurring sequences of channel and overbank fluvial sediments characterized by 0.5 - 1-meter-thick sandstones overlying mudstone intervals up to 2 meters thick."

Size class: macrofossils

Preservation: cast, trace

Collection methods: surface (float),

• This particular site is one of three within the middle shaly unit of the Salt Wash Member. The largest infilled track structure is greater than 1 meter across and greater than 1 meter deep.

Primary reference: G. F. Engelmann and S. T. Hasiotis. 1999. Deep dinosaur tracks in the Morrison Formation; sole marks that are really sole marks . Utah Geological Survey Miscellaneous Publication 99-1:179-183 [J. Alroy/R. Whatley/M. Uhen] more details

Purpose of describing collection: taphonomic analysis

PaleoDB collection 13277: authorized by John Alroy, entered by Robin Whatley on 12.02.2002, edited by Margaret Shalap

Creative Commons license: CC BY (attribution)