Amphibian Footprints from the Mississippian of Virginia

Abstract

In the summer of 1908 a geological field party from Oberlin College collected a series of amphibian footprints from the Mississippian of Giles County, Virginia. The horizon of the prints was near the bottom of the Hinton formation, but as the line of demarkation between the Hinton and the underlying Bluefield formation is not sharply drawn it was impossible to determine the exact distance above that contact. The Bluefield in this region is about 1,300 feet thick according to Campbell, and the Hinton about the same thickness. The horizon of the tracks is about 1,300 feet above the Greenbrier limestone which lies just below the Bluefield, and 1,300 or 1,400 feet below the equivalent of the Pottsville. According to Stevenson the Bluefield and Hinton are to be correlated with the upper part of the Mauch Chunk of Pennsylvania, and it was from the Mauch Chunk of Pennsylvania 700 feet below the Pottsville conglomerate that Sauropus primevus Lea was collected. The Hinton shales, like the Mauch Chunk, seem to have been subaerial in origin and are made up for the most part of variegated shales interbedded with thin layers of argillaceous, fine-grained sandstone. The footprints occur in fine-grained sandstone, and remains of land plants are not uncommon in the same beds. No marine fossils were noted by the writer in his examination of the Hinton excepting in one horizon, and that probably represented a brief transgression of the sea over delta flats. The fossils were rare and belong to only four or five species. Twenty-two footprints made by one animal walking in a straight course were collected in a slab. They give the impression of having been made by a bipedal animal for part of the distance, but after the fourth print of the right foot impressions of the forefeet appear. The distance from tip of toe to tip of toe in the first prints is about