That the trench showed up in Areas A and B of the 1966 test excavations (Greer 1967:5-6), which were in line with and on either side of our Unit D, confirms that this feature continued to the west and east. Identification of the feature as a defensive trench was suggested by the location of such a feature on the Labastida map (Figure 4).
Unit E
Unit E was a 5-x-5-ft unit, consisting of two sections: E and E-l. The unit was laid out across one possible line of an extension of the eastern wall of the convento. The purpose was to determine if a wall had been in existence here at any time during the mission period or later and, if so, how it had been constructed.
As in the other excavation units, the layer of recent fill was removed without screening, in this case to the 12-inch level, at which point the red-brown fill of the sewer pipe trench began. Above this level, two iron water pipes had been encountered. The cinder layer found in the other units appeared here at 12 inches, below which was 12 inches of tan clay containing late- nineteenth-century rusted metal, glass, brick, and whitewares. At 24-28 inches the cobblestone layer appeared. Beneath this level, the deposits divided into three distinct sections. An area in the center approximately 33 inches wide consisted of an adobe-like material of hard, tan clay containing chunks of caliche. To the west was an area of brown, sandy clay containing Spanish-period artifacts, bone, and charcoal. To the east was a soft tan sandy clay which contained fewer Spanish-period artifacts and no charcoal. An animal burrow disturbed this area and the central feature, which could account for a few whiteware sherds present in this deposit.
At 34 inches we decided to remove the southern half of the unit to obtain a cross section of the central feature and to examine its relationship to the surrounding area. Sterile, dark brown clay was found to slope downward to the north and west at ca. 36-50 inches. On top of this brown clay, and with the same slope, was a hard layer of white, sandy, lime mortar, varying in thickness from 1-3 inches. Beneath the adobe- like surface, 2-3 inches thick, were several layers of ash, charcoal, and bone, which directly overlay the sterile clay subsoil and the white mortar.
The western section of the unit was found to drop into a ditch-like feature running north and south, the limits of which were outside Unit E. At the end of Phase I, the true nature of the ditch, the adobe surface, and the other associated features remained unclear.
Phase II Excavations
Unit EII (Figure 10), south wall profile.
A jackhammer was used to remove a section of the 1926 wall foundation and the adjacent side- walk on the north, making an opening of 9 ft 8 inches east-west and 7 ft 3 inches north-south. All loose rubble was removed from the 1926 wall trench and from the yellow sand used as bedding material beneath the sidewalk, and the area was cleaned. It was immediately obvious that the rubble in the area just west of Unit E was not a wall, but rather a rubble zone several feet wide with no well-defined limits.
We began removal of this rubble from the southern half of the unit, and found it was 20-24 inches thick and 70-75 inches wide. Its upper surface was 22 inches below the north courtyard ground surface. Several of the stones were nearly two feet long, but all were randomly placed, with a sticky, tan, sandy clay between them. This clay had a high content of charcoal flecks and a few artifacts, including early nineteenth-century whitewares.