Mussel Shells on the Southern High Plains — Research at Macy Locality 371

Summer 2017 the Landmark research team discovered a new hunter-gatherer campsite located along the Southern High Plains surface at the edge of the eastern escarpment breaks at the Post research area near Post, Texas. Several hearths were noted eroding out of the the high plains surface along with hearthstones, grinding stones for processing plant material, and flaked debitage and stone tools. This campsite was recorded as Macy Locality 371 (Figure 1). Over 40 objects were mapped and collected from pedestrian survey, and a feature containing the remains of mussel shells was excavated.

Figure 1. Macy Locality 371 located at the edge of the Southern High Plains near Post, Texas

All of the objects observed from survey were found eroding from the top 50 cm of the high plains surface soil. Most of stone tools were made from Ogallala Formation gravels that were carried up from the escarpment breaks to the site for reduction. The grinding stones were made from local sandstone outcrops also carried up to the site from below. Most of the hearthstones used in the campfires were caliche rock procured just a few meters below the site from caliche caprock exposures.

Excavation of the mussel shell feature revealed a total of five shells. Three of the shell were stacked inside each other (Figure 2). Although mussel shell is found at archaeological sites in this region, they are not very common in comparison with other parts of Texas.

Figure 2. Three mussel shell enclosed into each other

Mussels are bivalve mollusks, two valves (shells) that surround the fleshy body. Fresh water mussels such as these live in a mixture of mud, sand, and gravel at the bottom of rivers and creeks. Mussels get food through filtering water for small plants, animals, and algae. They, therefore, require fresh running water. Mussels do not move much and use a muscle foot to burrow within bottom river sediment. During the larvae stage, mussels are parasites and attach to the gills and fins of freshwater fish to hitch a ride along waterways.

Mussels are a food source for past peoples, and their shells are often shaped for use as tools or commonly used to adorn necklaces as beads or shaped into pendants. The discovery of this mussel shell feature has led to several questions requiring future research. Identifying the type of mussel shell is first necessary to determine if it is a local species native to the south fork or was traded from outside of the Post research region. If the shell was traded, than that would suggest the shell was meant for making decorative items or tools. If the mussel could have been can be procured locally, then this feature represents the leftovers from eating them. The mussel shells are extremely fragile and were carefully wrapped in plaster in the field before removal to ensure they remain intact for final conservation at the Landmark’s conservation lab. Removal of the mussel shells from the jacket is an important activity scheduled for work at the Landmark’s lab over this winter.

The age of the Macy Locality 371 campsite also is unknown. A piece of charcoal recovered from near the mussel shell feature should provide a reliable date as to the age of this feature. Another important research question is determining the function of this campsite in hunter-gatherer landscape-use strategies. The Landmark research team has documented other nearby prehistoric sites at the edge of the high plains surface (Figure 3).

Figure 3. Landmark research team mapping and collecting objects at Macy Locality 371

At these sites, many of the resources, including water, has to be procured at the bottom of the escarpment breaks and carried up to the site. Possible incentives to camp at the edge of the high plains are the spectacular view of the valley below, and possibly for processing mesquite beans as evident from the discovery of grinding stones at the site. These are important research questions that will be investigate with further fieldwork and laboratory analysis.