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.
