Archaeology Update — Documenting the Long Barrack’s Walls

Kristi Nichols, Director of Archaeology, Collections and Historical Research

September 23, 2019

There were no archaeological investigations conducted as part of the Safety Bollard Installation Project during the week of the 16th. Since shovel testing conducted by the University of Texas at San Antonio’s (UTSA) Center for Archaeological Research (CAR) was completed in the areas that are open, and no additional excavations were planned, there was no need for the archaeologists from CAR to be on site.

The archaeological investigations conducted by Raba Kistner concentrated on documentation of excavation unit walls. The archaeologists on the interior focused on the final documentation of the structure foundation and the layers of soil noted in the unit walls. The archaeologists draw scaled profiles of each wall of the excavation unit that includes information about the location of soil changes, soil types, soil color, the presence of features, and artifacts that remain in the unit walls.

Since all three units excavated within the Long Barrack have reached the base of the foundation, no additional excavations are planned. A final laser scan of the completed units will be conducted to add to the documentation record. Once the archaeologists have completed all necessary documentation, the units will be examined by the Historic Architecture Team as they collect information concerning construction methods and materials, differences in mortar composition, impacts and more recent repairs to the foundation, and the presence and types of mineral salts.

Excavation Units 11 and 12 within the Long Barrack will be turned over to the Historic Architects by the end of the week. The Historic Architects have begun their review of Excavation Unit 9.

Archaeologists examining stone inside excavation unit — Figure 1. Examination of the soil stratigraphy by the Raba Kistner Principal Investigator and Archaeologist.

Archaeologists inside excavation unit — Figure 2. Documentation of the unit wall profile.

On the exterior of the Long Barrack, the excavation units reveal differences in the construction of the structure. In the central portion of the west wall, Excavation Unit 10 appears to have encountered the bottom of the foundation. The unit exposed limestone rocks not associated with the foundation at approximately 130 cm (51.1 inches) below the datum. For reference, a datum is a set point in each unit from which the depth measurements are taken to insure consistency when recording the data.

Some of the stones were removed to see if there were additional cultural deposits or information to be gathered about the base of the foundation. The archaeologists excavated to approximately 150 cm (59 inches) below the datum by the end of the week. Very few artifacts were recovered during the excavation of the levels this week. The last level excavated at the end of the week produced a couple small chipped stone fragments.

On the north end of the Long Barrack, Excavation Unit 13 progressed slowly to allow for the Structural Engineer of the Historic Architecture Team to examine the foundation. Mentioned last week, it appeared that there were some missing stones from the foundation that caused the Structure Engineer to be concerned.

After further inspection, it appears that although there is evidence of some impacts to the exterior of the foundation of the north wall of the Long Barrack, solid stone was found set back approximately 15 cm (5.9 inches) from the face. After consulting with the Structural Engineer, the archaeologists were given direction on how to proceed in the unit without increasing stress to the wall. The area has had an enclosed weatherproofing system that is ideal for preventing the elements from causing damage that could undermine the foundation should we have rain in the near future.

Archaeologists removing dirt in between stones in excavation unit — Figure 3. Excavation of Unit 10; trying to remove dirt from between stones.

Archaeologist finding bedrock in excavation unit — Figure 5. Additional documentation of Excavation Unit 17 after encountering evidence of bedrock.

The Raba Kistner Archaeologists, after consulting with the Texas Historical Commission, continued excavations in Excavation Unit 17 located on the east side of the Long Barrack. It was decided to remove a caliche floor surface to determine what type of deposits were below.

After removal of the floor, excavations continued another approximately 40 cm (15.7 inches) below surface. At 130–140 cm (51–55 inches) below datum, it appeared that bedrock was encountered. Although there were a few stones that appeared to be sitting on top of the bedrock, the majority of the stone uncovered appears to be one continuous piece. No cultural material was encountered in the last level of excavations, although a couple small snail shells were observed.

The archaeologists worked with the Historic Architecture Team to place the next two units to be opened. Two excavation units are planned to examine the area between the Church and the Long Barrack to determine if there are any buried foundations that shed light on the relationship between the two structures. Clearing the area and construction of weatherproofing was done to prepare the area.

The archaeologists started on Excavation Unit 16, located at the south end of the Long Barrack arcade, on the east side, was begun on Friday. Excavation Unit 14 will be placed on the north side of a reconstructed wall north of the Church, east of Unit 16. This unit will be started during the following week.