The Moenkopi Formation in east-central New Mexico: stratigraphy and vertebrrate fauna
Jurgen A. Boy, Rainer R. Schoch, and Spencer G. Lucas
The Anton Chico Member of the Moenkopi Formation in east-central New Mexico is 3846m thick and is divided into three main units that differ in bedforms, bed thickness and abundance of conglomerates. The following lithofacies can be distinguished (1) floodplain siltstones, (2) fine- to medium-grained sandstones, probably deposited in broad channels, and (3) intraformational conglomerates with clasts of sandstone, siltstone and pedogenic concretions that mostly represent channel lags. Eight vertebrate-fossil-bearing levels are recognized; two of them are in sediments of ephemeral water bodies and yield articulated fossils of amphibians, whereas the other six levels represent intraformational, conglomeratic channel-fill deposits. One conglomeratic horizon is locally rich in isolated hones of amphibians and reptiles, and contains rare, well-preserved skulls. The Anton Chico fauna includes stereospondyl amphibians (Eocyclotosaurus, cf. Stanocephalosaunus), both known from the Holbrook Member of the Moenkopi Formation in Arizona, and archosauromorph reptiles (prolacertiforms, erythrosuchids, rauisuchians), which locally vary in abundance.
- Boy, Jurgen A.; Schoch, Rainer R.; Lucas, Spencer G., 2001, The Moenkopi Formation in east-central New Mexico: stratigraphy and vertebrrate fauna, in: Geology of the Llano Estacado, Lucas, Spencer G.; Ulmer-Scholle, Dana S., New Mexico Geological Society, Guidebook, 52nd Field Conference, pp. 103-109.