Archaeology Update — New Excavation Units Opened

Kristi Nichols, Director of Archaeology, Collections and Historical Research
September 30, 2019

Archaeological excavations associated with the preservation work for the Church and the Long Barrack continued with two new excavation units opened. One excavation unit was placed along the south end of the Long Barrack, on the east side of the arcade wall. The other excavation unit was placed just north of the reconstructed portion of the north wall of the sacristy.

From the previous weeks, excavations in the unit placed along the north wall of the Long Barrack resumed during the week. The structural engineer from the project team was able to assess the condition of the wall and gave guidance to the archaeologists on how to proceed. There was a small delay to restarting earlier in the week due to some wet conditions in the unit. Some water from one of the weekend rainstorms had seeped into the north part of the unit, away from the wall foundation, causing some muddy conditions. The archaeologists had to allow for some time to dry out.

While that was occurring, the historic architect team was able to conduct a few scans of the exposed portion of the foundation. Once excavations resumed, the archaeologists were encountering dark soils with few artifacts.

Excavation Unit 14, one of the new units started this week and located near the exit of the Church, encountered dark, clay soils and signs of modern disturbances. The unit was placed in this location to determine if the reconstructed wall sits on top of original foundation as well as confirming whether a foundation alignment continues to run to the north, possibly representing the eastern wall of the Convento Courtyard. An electrical line was observed in the unit that ran north-south, then turned to run east-west.

In the northwest corner of the unit, archaeologists uncovered a section that contained concrete. As the excavations progressed to approximately 30 cm below datum, a slight soil change was noted in the northern portion of the unit, possibly indicating that the archaeologists are soon to get out of the disturbed and more modern zone. The sticky clay soils the archaeologists encountered contained fragments of red brick, glass, metal, nails, and a few ceramic sherds. One item of interest, although appearing in soils that are likely disturbed, was a whet stone. Excavations will continue in this unit during the following week.

Archaeologist inside an excavation unit
Figure 1. Excavations at Unit 14, north of the reconstructed wall of the sacristy.
Artifact stone used to sharpen knives, axes, swords, etc.
Figure 2. Whet stone recovered from the dark clay in EU-14.

Excavation Unit 16, the other new unit that was opened this week, was placed near the excavations that were conducted in 2006 by the University of Texas at San Antonio’s Center for Archaeological Research. Excavation 16 was place in this location to determine whether there is a buried foundation to a wall that would have run east, towards the Church.

In 2006, the archaeological field school opened a block of units along the south wall of the courtyard. The block of units measured 6 meters (19.6 feet) by 2 meters (6.5 feet). During the field school excavations, rubble related to the demolition of the east wall of the Long Barrack was observed, but those units were placed just to the south of where the possible foundation may be.

At approximately 30 cm (11.8 inches) below datum, the archaeologists uncovered what appeared to be a compacted caliche layer in the southern portion of the unit. Approximately 10 cm (3.9 inches) deeper, in the northern portion of the unit, under layers of rubble, large stones forming an alignment running east-west was encountered. As it is too early to determine if the alignment is part of a wall that created another series of rooms, the presence is promising. Archaeologists laser scanned the unit, as well as mapped the alignment to compare to historic maps of the compound, potentially leading to a better understanding of the stones.

Artifacts have consisted of a mixture of materials dating to several time periods. A possible door latch or handle was recovered while working in the area below the compacted caliche surface. Excavations were planned for the following week to open the unit up further to expose additional stones in the alignment, if they exist.

Archaeologists inside an excavation unit by the Long Barrack
Figure 3. Excavations at EU-16. Member of the Historic Architecture Team collecting data about foundation.
Hand holding an artifact that appears to be a door latch
Figure 4. Possible door latch or handle recovered from EU 16.

The Historic Architecture team conducted documentation in the finished excavation units in and around the Long Barrack Units.