The Shell Midden

Shell middens are essentially garbage dumps; the remains of many shellfish meals. Found mainly on the coast, Southeast Texas middens are mostly Rangia cuneata, with some oyster mixed in. Some middens are quite large, being hundreds of yards long, dozens of yards wide, and up to 30 feet deep. In Southeast Texas, midden depth seldom exceeds 3 feet. The larger middens have been mined for road construction material.

The depth of the midden gives an indication of how long the area was used. Excavations of shell middens reveal pottery sherds, stone tools, lithic manufacture waste (debitage), and bone. Radiocarbon dates can be determined from this shell.

Middens can be well stratified, with Archaic era artifacts below Ceramic era artifacts. In turn, these are below the Proto-Historic era finds. Stratification allows us to learn quite a bit about Southeast Texas prehistoric lifestyles. The data gathered can be used to study development patterns, and cultural and technological change. Middens also provide some insight into the geology of the area. Rangia require brackish water. Gaps in the archeological record (no one lived at the site) indicate water conditions weren't right for Rangia growth. Shell middens in Southeast Texas are usually not just piles of shells. The shells seem spread in a deliberate manner, paving large areas, probably to improve the living surface.

Excavating shell midden sites can be challenging. When dry, the mixture of shells, clay, and silt can take on the consistency of concrete. Shell interiors fill with clay and silt, concealing artifacts. On the up side, shell middens gives good preservation of bone.

Shell middens have proven to be extremely important archeological resources. Several hundred Rangia shell midden sites have been recorded on the coastal margin of Southeast Texas. Many of these are quite large, having several tons of shell, and have long occupation sequences. For example, site 41GV53 in Galveston County occupies three acres with a shell depth of one meter. Radiocarbon dating sets the earliest occupation at 4220BC.

The photos below are of a shell midden site on Galveston Bay. This site is being destroyed through wave action and subsidence. Portions of this midden are partially underwater, visible only during very low tides.

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