Schloenbachia trinodosa
Duck Creek Formation
Lower Cretaceous (Albian)
Pecos County, Texas
Sold to Ramses Moreno Milagro

This specimen is top quality for the locality and would be a great addition to any display collection. It is 11 1/2 inches maximum diameter. It has excellent node development. This specimen includes an additional piece of matrix that exhibits a perfect mold of the ammonite. While collecting this specimen it was tapped with a hammer and the matrix parted perfectly revealing the prize ammonite. The innermost whorl is restored.

The genus is small to large-sized with evolute coiling and deep, narrow umbilicus. The inner-most whorls are restored. The whorl section is taller than wide and is subrectangular or squarish. The venter has a low keel and appears squarish rather than rounded. Ribs are straighter and more widely spaced just before the body chamber. Three rows of coarse, equidistantly situated tubercles (nodes) occur: Umbilical, lateral, and ventrolateral. Nodate to clavate ventrolateral tubercles are particularly prominent.

In Pecos County the Duck Creek is about 20 feet thick and contains a prominent ammonite fauna dominated by Schloenbachia and Eopachydiscus. The Duck Creek appears to be conformable to the underlying Kiamichi Formation. The formation is a soft chalky , nodular, whitish, argillaceous limestone rich in fossils. The basal ledge that caps the Kiamichi contains a prominent of fossil oysters and the echinoid Macraster.