AN INVENTORY OF MIDDLE JURASSIC MOLLUSKS AND THEIR STRATIGRAPHIC SETTING AT FOSSIL POINT, LAKE CLARK NATIONAL PARK AND PRESERVE, ALASKA

Fossil Point is an important paleontological locality situated within Lake Clark National Park & Preserve, Cook Inlet, Alaska. The locality contains one of the most productive marine invertebrate fossil sites known in Alaska. The Middle Jurassic Tuxedni Group contains exceptionally rich and diverse megainvertebrate faunas: ammonites, bivalves, and belemnites. The most obvious fossils are the large and abundant inoceramid bivalves. A field study was conducted during August 2014 by the National Park Service evaluating the paleontological and stratigraphical setting of strata exposed at Fossil Point. A large number of fossils were collected and stratigraphic control for the fossils was completed by measuring stratigraphic sections.

The bivalve fossils of Tuxedni Bay were first described and illustrated by Eichwald (1871). Four new inoceramid species (Inoceramus ambiguus, I. porrectus, I. eximius, and I. lucifer) were established by Eichwald, and there has been subsequent debate by paleontologists as whether they are valid or merely represent ecological variants belonging to one or two species. During this study, we collected four distinct species that we believe represent the four species identified by Eichwald.

Little has been reported about the Pleuromya and Pholadomya bivalves that are abundant in all the strata at the site. We collected four distinct species of the genus Pleuromya that include P. aleutica, P. dilitata, and P. aldaini(?). One species yet to be identified is similar to P. aleutica, but has a less pronounced posterior enlargement. We found one specimen of Pholadomya sp.

Classification of the common belemnite fossils of the Tuxedni Group is lacking. Classifying the few belemnites collected may hold important clues to the biogeography and migration patterns of this common fossil, and is presented by Schraer et al. in this session.

Fossil Point is located in a remote and difficult to access location. The fossil collection housed at the NPS Alaska Region Curatorial Center will be available to the public and park staff for research and education. To promote research in the park and better educate park visitors and staff, three dimensional models of the fossils are being created and shared with scientists and on the web. These 3D models are presented by Wood et al. in the Ray Troll fossil art session.