Long Barrack Archaeology Update - January 12

January 12, 2024

Three excavation units were active this week: EUs 2, 4, and 6. Artifact processing also continued in the lab throughout the week.

In EU-2 archaeologists further exposed the stacked limestone alignment previously encountered in EU-3. This alignment is oriented north-south and is about 56 cm in width. The alignment has patches of mortar present and an associated prepared caliche surface. When excavating through the caliche surface a partial spur was recovered. Archaeologists also excavated the soils in the remainder of the unit, with a maximum depth reached of 100 cm below surface.

Excavations in EU-4 revealed a grey, ashy deposit that corresponds to the ashy deposit encountered in EU-5. Artifact counts are also similar to EU-5, with multiple ceramics, metal, and other materials recovered. EU-4 reached a maximum depth of 60 cm below surface.

This week archaeologists opened EU-6. This unit is against the Long Barrack wall and to the west of EU-5. Due to previous landscaping, this unit was very uneven resulting in a wide range of starting elevations. The first level for this unit was excavated throughout the week and archaeologists reached a maximum depth of approximately 30 cm below surface. Even though the soils exhibited signs of previous disturbance, five bags of artifacts were collected. Artifacts included ceramics, metal, glass, and construction materials.

Side wall of limestone in an excavation unit
Profile of Limestone alignment in EU-2.
Grey, ashy deposit in an excavation unit
Excavations in EU-4.
Flat stone surface in an excavation unit
Level 1 in EU 6.

From the lab:

All of the excavation units have recovered lithics, or stone tools. This week we would like to describe some of the lithic material archaeologists have recovered.

Stone tools, also referred to as lithics, are commonly found in archaeological sites across Texas.  Although lithics are often recovered from prehistoric archaeological sites, they are found within Mission occupations as well. The current archaeological investigations within the Long Barrack have rendered several types of stone tools; including gun flints, projectile points, informal tools, and debitage. Debitage, also known as chipped stone or flakes, is the debris produced during stone tool manufacture.

Initially, formal tools like gun flints or projectile points, originate from a chert nodule (or other material), that is continuously modified and reduced to produce a tool. The excess material discarded off of the chert nodule is what creates the debitage or chipped stone. Archaeologists can identify debitage by assessing specific characteristics present on the debitage itself. These characteristics can include a bulb of percussion, a platform, and a ripple; all of which are a result of the percussion impact during the manufacturing process. The debitage pictured, was recovered during the current archaeological investigations from different excavation units at varying depths. In the first image, note the various forms of debitage that archaeologists encounter during excavations. The second image shows the characteristics commonly found on debitage.

While not all flakes display these specific characteristics simultaneously, it is important for archaeologists to distinguish culturally produced debitage from mechanically produced debitage. Mechanical debitage is created by artificial or natural means, typically from machinery impacting natural chert or livestock crushing chert cobbles in agricultural settings. In some cases, mechanical debitage can look very similar to culturally manufactured debitage, in that it displays evidence of percussion impact.  However, due to the level of physical impact from machinery or large mammals, these characteristics are often not present or obviously too forceful to be produced by a human. The context in which the debitage is found also plays a vital role in determining whether it is cultural or mechanical. For example, the mechanical debitage pictured is associated with a builder’s trench found across excavation units 1 through 4.

Nine stone fragments next to a ruler for size
Figure 1. Debitage
Stone fragment next to a ruler for size
Figure 2. General characteristics of a flake
Seven stone fragments next a ruler for size
Figure 3. Mechanical debitage