CAVE DEPOSITS OF CENTRAL TEXAS

Fossiliferous cave deposits of central Texas have provided a record of the changes in the terrestrial fauna of the Late Quaternary. These deposits accumulated in caves that were formed in the late Early Cretaceous limestones of the Edwards and Georgetown formations of the Edwards Plateau. A few are from caves formed in the Ordovician Ellenburger Limestone in the Llano Uplift just north of the Edwards Plateau. At least 37 caves have been found ranging geographically from the Balcones Escarpment on the east to the Pecos River on the west, and from the southern edge of the Plateau to the southern edge of the Llano Estacado to the north. All known cave deposits are late Pleistocene or Holocene in age with one exception; Fyllan Cave, which has sediments with reversed magnetic signature and an Irvingtonian fauna.

The scarcity of older cave deposits and the fact that several caves with late Pleistocene deposits have closed entrances and were only discovered through excavation, indicates that caves did not stay open long and did not accumulate deposits over an extended period of time. Bones found in these deposits provide information on the development and behavior of Homotherium and Mammuthus, data on extralimital extant species and their pattern of disappearance from central Texas, examples of non-analog associations, and one example of a continuous late Pleistocene-Holocene record.

Future directions for investigations include: 1) more radiocarbon dates to refine the chronology of the late Pleistocene-Holocene faunal history; 2) explore cave deposits in the northwestern part of the Edwards Plateau, an area not well represented at present; 3) search for older deposits in quarries or other excavations; 4) search for potential Cretaceous-aged or older cave deposits in the Paleozoic limestones of the Llano Uplift.