North-side foundation (Spanish colonial?).
The foundations are constructed differently with different sized stones, differing degrees of skill or care, different widths, and
different ratios of mortar to rocks. This indicates different people built the north walls than the rest of the walls. Most likely this
indicates a time difference.
NORTH WALL -- Possible Spanish Colonial
Double adobe wall at north west end of excavations. It is
difficult to see in this image but the bricks are smaller in the
right wall than they are in the left (north) wall.
This image shows the adobe wall at south west end of
excavations. Bricks are visible with mortar between them.
The cobbles are set in mortar and seem to represent a type
of patchwork to stabilize the wall base at the intersection of
this structure and the existing building that is called the
Poston House. This patchwork was clearly added after the
wall because the beige-colored mortar and rocks are
pastedup against the bricks rather than underlying them.
Excavation Results (Deni Seymour)
A complex sequence of construction is indicated for the lot. This sequence seems to begin in the Spanish colonial period and extends into modern
times, when the lot was used as a dump. A small prehistoric scatter is also indicated but nothing on the order of a habitation site. No features
specifically related to the prehistoric period were encountered.
The large rectangular outline of a building foundation (shown in photo above) is actually a complex series of building and refurbishing episodes
where foundations were added, modified, and removed. This sequence of construction is discussed in a separate section (see below).
The high density of historic artifacts results from this portion of the lot being used for dumping household trash (ash, charcoal, fire-cracked rock,
pottery, glass, personal items of adornment [including jewelry], combs, coins, bottle caps, egg shells, faunal bone, construction debris [including nails,
wood, concrete, bricks, and stucco]) and also seemingly for discarding school supplies (chalk, pencils, marbles) and business debris (especially car
parts including shock absorbers). Artifacts, faunal bone, ash, and fire-cracked rocks were dense in this area indicating that household debris was one
of the primary sources of material. Artifacts were found on the floor and fill of the building suggesting that the abandoned rooms were used as a
repository. Pits were also excavated into which trash was placed. One of these underlies the easternmost wall and post-dates 1930, indicating that this
final wall was constructed fairly late. Two other pits cut the north and south walls, respectively, and seem to be filled with relatively modern trash.
The northern pit contained a plastic gallon jug, cinderblocks, bricks, and a household fuse. The southern pit was filled with automobile-related debris
including a head gasket, a hubcap, and a window crank. Many smaller pits intrude into the floor and fill of the building indicating smaller dumping
episodes. Given this, it is assumed that very little of the artifactual material recovered relates to the actual use of the structures. The density and
diversity of trash added to this lot through time obscures the original building-related assemblages.
Many later features intrude into the buildings. The base to what was once a large wooden cross, known to date at least as early as the 1940s, intrudes
into Unit 3. The cross itself was removed by the current landowner and was placed in a pile of debris at the north edge of the ridge. Two square posts
that were probably railroad ties are located in Unit 5. These were set upright into the ground, perhaps serving a fence posts. Several smaller round
postholes are visible in the floor; some still contain wood from their wood posts.
The north arrow points to a cluster of stacked rocks in mortar that have fallen
on their side adjacent to the Spanish colonial foundation. This is not wall fall
because the wall was made of adobe, not rocks. Rather this probably
represents a patch to the lower adobe wall that may have been damaged by
salt and water erosion, perhaps during years of neglect when the structure was
abandoned. Many modern and historic adobes exhibit this type of patchwork
in areas where the lower wall has been eroded. There are two places along
this wall and two along the southern wall where this type of patchwork seems
to have been used to stablize the wall. Interestingly, this patchwork suggests
that if this was a covered building this was on the outside of the building at
one time, and that more of the Spanish-colonial structure would have been
situated to the north. This is suggested because if the building remained
roofed the lower wall would not likely have eroded this way. If this was a wing
wall this type of erosion might have occurred on either or both sides of the
wall, but given the the prevailing wind and rain comes from the southwest it is
probably reasonable to expect that this side would have experienced greater
damage than the north side of the wall.
This remedy for lower wall erosion has been captured in
historic photographs of Tubac, perhaps for the same
building (see lower right).
Click here for BACKGROUND INFORMATION AND INTRODUCTION
THE FOUNDATIONS OF TUBAC FROM PRESIDIO TO THE POSTON-TERRITORY
HOUSES ON THE ELLINOR PARCEL (AZ DD:8:252, ASM)
RESULTS AND CONCLUSIONS
This images shows the fully exposed foundation, but lacks the intact adobe walls overlying the west end of the foundation.
Wall Construction Sequence (Deni Seymour)
A sequence of wall construction is discernable on the basis of foundation characteristics and abuttment attributes. The inferred sequence is
reconstructed as follows. The Spanish colonial foundation was constructed either as a wing wall or as a rectangular foundation that has been
destroyed except for a single wall. No evidence of a contemporaneous foundation was found to the north or south.
This 1854 image by Charles Schuchard shows Tubac's houses with wing walls made of adobe
that extend outward from the houses. These would have been defensive features that also
defined property boundaries.
This segment of the foundation thought to be Spanish colonial in
age is similar to the Spanish colonial foundations built in the
captain's quarters, now part of the State Park. It is distinguished
by small rocks carefully set in mortar. Even one of the adobe brick
walls overlying this foundation is made of bricks of the same size
and shape as those used for the captain's quarters. Post holes
abut the outer edge of this foundation, suggesting that these may
have been structural timbers.
The Spanish colonial foundation is labeled #A.
This English Transfer ware was found in the profile, under the east wall. This means that this part of the foundation dates later than this
(unless roots and rodents carried it there but not likely). Given this, we can say that the south and east wall was built late, while the
northern wall may have been built earlier, with the earlier foundations being incorporated into the later construction, as is typical in
Tubac. For this reason it is thought that the north foundation is from the Spanish colonial period. We had to cut the walls to determine
this for sure. The north and south walls are already cut by intrusive pits so we used those areas to breach the wall.
Profile of Bank Cut (Deni Seymour)
Sometime in the past cultural deposits in the area of the foundation were cut by a now gravel-covered acess drive and parking area in the south central
portion of the lot. This provided a cut bank or profile face along the west side of the drive that was bordered by bricks, railroad ties, and rocks. These
bordering materials were removed along with excess dirt that had been used as fill behind the border and the profile was faced to obtain and idea of
the cultural stratigraphy. What became apparent is that there are a series of additional features and intrusions, with sterile (pre-cultural) clearly visible
in the base of the trench. While there is insufficient time to investigate all of the features the profile shown below provides documentation of the more
varied activity. The largest feature is a pit with dark fill and artifacts from the 1930s. This is important because it shows that this portion of the foundation
post-dates the 1930s and accounts for its different character. Changes in the nature of the foundation suggest many different building and add-on
episodes, as is characteristic of Tubac. This also suggests that major land-modification activities have taken place on this lot, and so only a portion of the
earliest historic foundation is preserved. Pit-looking features shown in the profile may be tree wells, post holes, and, potentially, prehistoric features
although there is insufficient time to investigate these and other than the large pit there are no artifacts in them to suggest and age. Rodent holes
throughout portions of the profile and in the soft fill of these features indicates that artifacts may be moving from deposit to deposit.
Profile drawn by Jeremy Moss and Nicole Arendt and drafted by Nicole Arendt
Stylized Feature Plan and Intrusions
Feature 1: First wall
Feature 2: Second room and walls
Feature 3: Intrusive pit (late 20th century)
Feature 4: Intrusive pit (late 20th century)
Feature 5: Trash-filled pit in profile under east wall (1930s)
Feature 6: Rectangular post
Feature 7: Rectangular post
Feature 8: Cobble alignment that may have been a wall; probably goes with green
walls to the north and south
Feature 9: Wood base for cross (historic)
Feature 10: Final wall added after 1930
Cut along gravel
During this second construction stage (#B) a cross wall
(oriented north-south) was added at the same time the
south (running east-west) wall was built. This wall
foundation curves, forming a relatively continuous
foundation. From this we can tell that this was the end of
the building at this time.
Another wall that aligns to the east was appended later
(#C), extending the overall size of the building.
At some point the south west portion of the foundation was added using larger rocks that were not set as carefully into mortar.
This second stage is labeled #B.
This same cross wall that formed the east side of
the building abuts the Spanish colonial wall with
granduar adobe mortar added to make the bond.
This shows that this north-south cross wall (#B)
was added later and bonded to the existing
Spanish colonial wall (#A). When new rooms
were added to the east this cross wall became an
interior dividing wall.
Construction sequence in color.
Photo montage of entire profile
These adobe walls abutt the existing occupied structure referred to as the Poston House. The foundations align with
in-use walls, as shown in the photos above.
Close up of south end of profile showing wall overlying pit with this 1930s artifact in it. The
white in the lower portion of the profile is sterile clay.
The east foundation along north wall is located on the right side
of this photo.
Also shown to its south (left) is another unexplained cobble and
boulder construction that may be an interior bench or platform
or may have been another repair area that has fallen on its
A posthole is shown in this image. Three were noted along
the north edge of this wall indicating they were structurally
important to the building. The white flagging tape in the
image to the left also denotes the three postholes.
The overburden was much thinner than we initially thought, which allowed us to reach the floor in all six excavation units. Fill depth
decreased from west to east, owing to the natural gradient of the landform and also because the ground surface nearest the house was less
The stratigraphic sequence is fairly consistent across the entire feature indicating that once the rooms were finaly abandoned they were filled
with relatively late trash.
Stratum 1 is the loose wind-blown and water-lain brown sediments.
Stratum 2 is dark gray clayey and oily fill, rich with construction debris, ash, charcoal, and artifacts. This is post-occupational fill deposited
here from throughout the community. Artifacts suggest that the most intensive period of dumping was in the 20th century as car parts, modern
ceramics, metal, paint, and construction debris are found in floor contact.
Statum 3 is represented by the false floor (or later compacted surface) in Units 5 and 6. This is about 10 cm higher than the real floor and may
represent a use surface after the structure fell out of its original use. This does not continue across the entire floor because of disturbance and
perhaps also owing to differing ages and uses of the various rooms.
Stratum 4 is the floor which seems to be compacted clay that is nothing more than the underlying natural clay stratum. This surface is beige
but is mottled owing to disturbance and use. Postholes and intrusive pits cut through many areas of this uneven surface. The floor is best
preserved to the west. The floor is cut by later features and has been severely damaged, presumably from water saturation and subsidence, on
The walls are also best preserved on the west side. Adobe bricks are preserved over the foundations on the west side of the work area. Their
absence on the east side and the lack of abundant (but intermittent) adobe brick debris in the fill suggests that many of the bricks were
scavenged for use in other buildings. Adobe brick fragments in the fill were noted mostly on the west side where everything is better
preserved, having been closer to the standing Poston structure and also buried under thicker fill.
Wall Description: ...
A curve to the wall indicates a distinct building phase.
Plan Drawing by JJ Golio and Mike Golio
It is also important to remember that this portion of the lot falls between the Poston House on the west and the Otero House on the east.
Occupation of the lot during historic times was intensive and continues today. These walls connect to the Poston House. The foundations line
up with existing walls in the building to the west. Moreover, efforts to patch the junction between these foundations and the Poston House are
clearly visible (see below).
Looking at rock and mortar placed against adobe wall and
foundation to stabilize adobe wall at junction with Poston House.
Close up of mortar and rocks pasted against adobe wall to
support corner at abutment between Poston House wall and the
former building to the east. A clear line of demarcation is visible
between the whiter mortar and the grey adobe of the bricks.
Facing north at wall.