Isolated
vertebrate tracks from the Upper Cretaceous Capping Sandstone
Member of the Wahweap Formation: Grand Staircase - Escalante
National Monument, Utah
Tester,
Edward, Simpson,
Edward L., Bernard, Jonathan, Wolf, Hannah L., Tindall, Sarah S.,
Simpson, Wendy S., and Jenesky, Timothy, 2007, Isolated
vertebrate
tracks
from the Upper Cretaceous Capping Sandstone Member of the Wahweap
Formation: Grand Staircase - Escalante National Monument, Utah
[abs]: Rocky Mountain Section - 59th Annual Meeting (7–9 May 2007),
Geological Society of America Abstracts with Programs, Vol. 39, No.
5, p. 42.
Although track sites are common
throughout Late Cretaceous strata, few have been reported from the
capping sandstone member of the Wahweap Formation in Grand Staircase
- Escalante National Monument. Recent discovery of isolated tracks
preserved in the capping sandstone indicates that several track
makers including crocodylomorphs, previously known from teeth
elements, and ornithischians were present during fluvial deposition.
An isolated crocodylomorph pes track was found in fluvial deposits
at Wesses Canyon locality. The track is 14 by 10 cm and has five
digits with divarication of approximately 60º. These measurements
are consistent with other crocodylomorph tracks from the literature.
At Tommy Smith Canyon near the contact of the capping sandstone
member and the overlying Kaiparowits Formation, several isolated pes
tracks occur that range from 16 to 32 cm in length and 9 to 27 cm
wide. Tracks have three distinct digits with a divarication of 50º
to 75º. These tracks are assignable to an ornithischian track maker.
A possible therapod track is present based on size and morphology,
but does not display definitive criteria.