Date of Graduation
Bachelor of Science
This study began with a general survey of Washington Mountain that identified the stratigraphic units outcropping. While doing so, the Wedington Member of the Fayetteville Shale and the Pitkin Limestone were both found on the north face. Both units had been previously mapped as pinching out further south. The discovery of a fossil bed in the upper portion of the Cane Hill on Washington Mountain provided a rare opportunity to study the ecology of early Pennsylvanian fauna. Though the sandstone bed was poorly preserved, 14 separate genera were identified and their ecological niches were compared in an effort to establish the invertebrate community that comprised the bed. Genera identified consisted of Composita, Dielasma, Rhyncopora, Delocrinus, Acrocrinus, Perimestocrinus, Echinocrinus, Rhombopora, Septopora, Amplexus, Straparollus, and Paladin. These are all typical of a Lower Reef Slope community. These organisms tended to occupy clear, warm, shallow waters some distance from shore. The more fragile among them suggest they occupied the calmer waters below the wave base. Deeper-water organisms such as Paladin suggest a depth close to 50 meters. The presence of the exotic minerals zircon, plagioclase, muscovite, and phyllite suggest a deltaic influence into the area. As a whole, this site is consistent with the transgressive marine setting of previous interpretations of the Fayetteville Quadrangle.
Hamlin, S. (2012). The Paleoecology of a Morrowan Fossil Bed, Washington Mountain, Fayetteville, Arkansas. Geosciences Undergraduate Honors Theses Retrieved from https://scholarworks.uark.edu/geosuht/1