It should also be noted that this is just the latest lowering of Gulf sea level during the Pleistocene — there were earlier highstands and lowstands.By 14,000 years ago, sea level was rising rapidly because of ice sheet melting.Radiocarbon and OSL (optically stimulated luminescence) dates on the Beaumont/Prairie Formation range from roughly 28,000 to about 135,000 calendar years B. Mc Faddin Beach alone has produced more Clovis points than any single county in the state of Texas — over a hundred of them.
Backhoe testing (in 19) on both sides of Highway 87 has shown that the Pleistocene Beaumont Formation lies less than 2 meters below the ground surface, overlain by sterile Holocene sand and clay representing swamp and marsh deposits. Although artifacts from essentially the entire known span of Texas prehistory are represented, the most striking aspect of this place are the extraordinary numbers of Paleoindian and Early Archaic projectile points that have been discovered here.
In 1992, the Bureau of Economic Geology (UT Austin) sank a series of geologic cores along the coast, including three on or just offshore from Mc Faddin Beach.
In 1994-96, Melanie Stright, an archeologist with the Minerals Management Service (US Dept.
If we rely on the Barbados coral data, by about 13,300-13,500 calendar years B. (when the archeological record at Mc Faddin Beach begins with the deposition of Clovis points at the source area) sea level still stood about 65-68 m below the present level, the shoreline was still 175 km away, and the site area still well inland. P., when various types of Late Paleoindian projectile points were being deposited at the site, sea level had risen to 20 meters below the present level. P., a barrier shoreline developed about 55 km southeast of the Mc Faddin area. By the time these were discarded, the source area may well have been flooded, which raises the possibility that these most recent artifacts might have been discarded on the beach, rather than washing ashore like the earlier material. Two lines of vibracores punched across the valley axis contain pine, oak, juniper, cypress, grass, sedge, and other pollen types suggesting vegetation similar to that found on the coastal plain today.
The rate of sea level rise (and flooding of the continental shelf) was especially rapid in the early Holocene from about 9000 to 7000 cal B. Without knowing where the actual source area for the Mc Faddin artifacts is located, it is impossible to say exactly when the area was flooded and rendered inaccessible for habitation, but there are some artifacts from the beach that Stright classifies as “transitional Archaic” (about 2350-1250 cal B. During the period of lowered sea level, the combined channels of the Sabine River and Calcasieu River incised the exposed continental shelf, running southwestward roughly parallel to the present coast and about 30 km out from it, joining the Trinity River channel, then turning southward. (buried under Heald Bank) have been cored offshore. P., the shoreline was still some 50 km away; by 5300 B. What happened after the middle Holocene, or about 6000 cal B. One group of geologists insists there has been a fluctuating series of late Holocene — periods during which sea level actually stood higher than today and covered part of what is now dry (well, dry to marshy, perhaps) land, evidenced by a series of inland beach ridges radiocarbon dated to that period.