Quaternary antelope remains from a second cave deposit in the Organ Mountains, New Mexico

Abstract

Explorations conducted by Mr. Roscoe P. Conkling during the past two years in the Organ Mountains of southern New Mexico have led to the discovery of two limestone caverns in the lower spurs of this range. Attention has been directed to the deposits of Conkling Cave. The second occurrence is that of Shelter Cave, situated in Paleozoic limestones exposed on the west flank of Bishop's Cap (Pyramid) Peak, approximately two and one-half miles west and south of Conkling Cave. In the course of preliminary excavations in this cavern a vertebrate assemblage was collected including among other forms a horse (Equus), the ground sloth Nothrotherium, and a peculiar type of antelope. The remains of these mammals were all found, according to Mr. Conkling, within 48 inches of the present floor of the cave and imbedded in a gray ash deposit. The presence of the horse, ground sloth and antelope indicates a Quaternary age of the cave deposits. No less than three individuals of the new antelope are recorded. A second type of antelope, larger in size than the first and approaching more closely the modern pronghorn in several characters, is represented by fragmentary specimens in the collection. Whether or not the two forms were contemporaneous has not been definitely determined. The preservation of the jaw and limb material of the larger antelope is somewhat unlike that of the specimens referred to the new species and is perhaps indicative of later age. The interest which attaches to a group so distinctively North American as the Antilocapridae and the unique characters presented by the small antelope from Shelter Cave make a description of the remains desirable in advance of a more detailed investigation of the deposit and fauna.