Field and Lab Methods
Our 2007 excavations at Zatopec expanded upon previous work at the site. In order to accurately and strategically place new units in positions where no excavation was previously conducted, three excavation units from the 1980s were exposed with a Gradall (similar to a backhoe). Based on these old units, CAS archaeologists were able to locate the former excavation grid, and then identify previously unexcavated areas of the site. Since previous investigators reported the discovery of domestic features and debris in a particular location, CAS excavations focused on that area. The first phase of new units in 2007 were all 1-by-1 meter square, and were excavated in 10 cm levels. Excavating in this fashion allows archaeologists to remove a controlled volume of sediment, which in turn makes it possible to map the distribution of artifacts recovered from each unit and level across the site. This is a common excavation method in areas where natural stratigraphy (layers) are difficult to discern. However, these so-called arbitrary levels frequently cross-cut natural or cultural stratigraphy.
Tools used in excavation included shovels, picks, trowels, brushes, and whatever other materials were useful for efficiently moving sediment while keeping track of artifacts' provenience, or precise three-dimensional location. As artifacts were encountered in situ (latin for in place), their locations were recorded, and they were illustrated on an illustration of the unit. All excavated sediment was passed through 1/4-inch screen, and some of the sediment was passed through a series of smaller screens in order to recover material at a finer fraction. Artifacts recovered by screening were placed in bags corresponding to the unit and level from which they came. In addition to measurements, records, notes, and illustrations, many photographs were taken to record excavation and artifacts.
Following the excavation of these 1-by-1 meter units, the site was again mechanically excavated with a Gradall to ensure that no unidentified and significant features went unrecorded. This exercise resulted in the discovery of several other features, including prehistoric human burials. Following a period of consultation with the appropriate authorities (the Texas Historical Commission, Native American tribes, and other sponsoring agencies), human remains were removed with utmost care. As they were removed, each element was measured, recorded, and mapped, and then placed in a protective aluminum foil package for safe keeping in a secure room at CAS designated for human remains.
Once artifacts left the field and entered the Center for Archaeological Studies building on the Texas State campus, they were subjected to a series of processes to ensure safe-keeping and accurate records of provenience. These processes typically included washing, labeling, categorizing, and cataloging, all the while keeping track of each artifact's origin. This takes a considerable amount of time, patience, and concentration, but it lends to the ultimate goal of being able to "recreate" the site through maps and narrative-style reports. Archaeological sites are limited resources, and once artifacts are removed, they cannot be replaced in their original context.
In the field, artifacts from the same unit and level are separated by material or type (i.e., bones, lithics, pottery, etc.), but these separations are refined in the lab. After artifacts are washed and dried, they are briefly examined and placed into one of several categories, including but not limited to, projectile points (by type), bifaces, expedient tool, core, debitage, ground stone, faunal remains, botanical remains, ceramics, etcetera. Following the initial preparation of artifacts and records, analyses began. Each analysis requires a slightly different method of refining the intial categories. These are further explained in the following pages.