In Search of El Presidio de Tucson

In Search of El Presidio de Tucson

J. Homer Thiel, Desert Archaeology, Inc.

Map of the trench excavated in the west lawn of Tucson City Hall.

It is easy to forget, as one views the skyline of modern Tucson, that our community has its origins in a small Spanish fortress. In 1775, Captain Hugo O'Conor selected a piece of land on the east side of the Santa Cruz River for a presidio. Over the next eight years adobe walls were built to enclose the area to protect people inside the fort from Apache attacks.

Today the walls are lost, buried in the heart of Tucson below streets, lawns, sidewalks, and buildings. In order to find them, we must examine historic documents and old photographs, excavate trenches, and study artifacts.

Over the last 10 years, the Center for Desert Archaeology has initiated several research projects to look for remains of Tucson's Presidio. In 1991 we worked with Karl Glass of the University of Arizona on a ground-penetrating radar study that suggested that portions of the Presidio wall were intact beneath the ground surface in several areas. The following year, Center volunteers helped excavate trenches in the Pima County Courthouse courtyard, ultimately exposing a north-south adobe wall which rests on a stone foundation. This is thought to be the east Presidio wall, perhaps a portion dating to the remodeling of the wall in the 1820s.

The City of Tucson recently acquired the northeast corner area of the Presidio, which lies beneath a parking lot. The City and Pima County have ordinances protecting cultural resources; however, development activities, such as utility installation, can still impact Presidio period archaeological remains. A better understanding of what lies buried beneath the ground will aid in the development of a master plan for the Presidio area, helping guide future activities.

In March and April 1998, the Center returned to search for portions of the south, west, and north walls of the Presidio. Trenches were excavated in five areas by volunteers who carefully screened dirt and bagged artifacts. Undisturbed archaeological deposits were found in most areas. Especially exciting was the discovery of a complex of features in the lawn area on the west side of the City Hall.


The curving rock wall

The Presidio of Tucson

The walls of the Presidio were reported to have run along Washington Street on the north, Church Street on the east, Pennington Street on the south, and Main Avenue on the west. Each side of the Presidio was about 750 feet long.

The wall was reported to have been between 18 inches and 4 feet thick and between 6 and 16 feet tall. We have no contemporary descriptions of the wall; instead, we rely on accounts preserved by people in the 1920s and 1930s and, as a result, we have many conflicting details.

Inside the fortress were homes, barracks, and stables built against the interior walls, a cemetery and church on the east side, a commander's house in the center, and several plazas. A pair of gates pierced the west and east walls, roughly where Alameda Street meets Main Avenue and one on Church Street at Alameda. The wall helped protect the community against attacks by Apaches, but by the 1850s this threat had subsided and the wall was demolished, with many of the bricks serving as building materials for Territorial period homes. The first map of Tucson, drawn in 1862, appears to show the general outline of the wall, especially the north and east sides. The last known standing portion of the wall was torn down in 1918.


A North-South WallNorth-South Wall

The earliest historic feature found was a segment of a north-to-south adobe brick wall. The surviving portion of this wall was built from pinkish-brown adobe bricks, each measuring 19 inches long, 11 inches wide, and 4 inches thick. The bricks were plastered together with a gray-brown mortar. Two courses rest on a wider foundation that is about 32 inches wide and consists of three adobe bricks resting side-by-side, held together by a lighter-colored mortar. The basal course of bricks was placed on the existing historic ground surface. Excavations beneath this surface recovered only prehistoric artifacts. On the west side this surface dips down dramatically, whereas on the east side it is relatively flat.

What does this wall represent? Examination of the soil profiles by geomorphologists indicates that it is the earliest historic feature in the trench. There were no interior abutting walls in the trench area when it was first built; thus, it may be a freestanding wall. The drop on the exterior suggests that it was being built next to a sloping area or that the dirt on the exterior had been removed, perhaps to make adobe bricks. By building next to a slope or by removing sediments, the wall would be higher to people standing outside. The flat interior surface allowed structures to be built against the wall.

One possibility is that this is the west Presidio wall. It is in the correct location, according to historical sources, and is the earliest historic feature in the area. The bricks are also the correct size for the Spanish and Mexican period. Lastly, artifacts in close association with the wall date to the Presidio period (1775-1856) rather than the later American Territorial period (1856-1912). On the other hand, some archaeologists have suggested that the wall may not be wide enough to be the Presidio wall. The northeast corner area found by Emil Haury and Ned Danson in 1954 was 3 feet wide (although this may represent the corner tower) and the walls for the Presidio at Terrenate are also wider. One way to resolve this problem is to return to the lawn and excavate to the north and south. If the wall is continuous, it is likely that it is the Presidio wall.


An Interior Room

One clue to the antiquity of the wall is the fact that some time had elapsed between the construction of the north-south wall and the construction of the first structure built against the wall in the trench area. Fragments of adobe brick, perhaps broken off from the top of the wall or discarded as the wall was built, lay on the original ground surface inside the wall. Several inches of dirt had built up against the wall before a single layer of rocks was used as a foundation for an east-west wall. On top of this a single course of 11-inch-wide pinkish-red adobe bricks survived, although only portions of a few bricks were present. Pottery Sherds

Inside the structure was an area of prepared adobe that had been used as a hearth. The adobe was fired a bright red color and a lens of ash lay on top. Artifacts found in this structure were mostly historic Native American ceramics, although one musket ball was recovered. No Territorial period artifacts were found, suggesting an early date for its construction.

Toward the back of the trench, past an area disturbed in the 1960s, we found a Presidio period trash-filled pit. The pit contained many layers of white ash interspersed with layers of brown sand and bits of charcoal. The base of the pit was irregular, suggesting it may represent a borrow pit, where dirt was dug out to make adobe bricks or plaster. We only excavated a small portion of this pit; however, the recovered artifacts indicate that it was created during the Presidio period, from the 1770s to perhaps as late as the 1850s.

Preliminary analysis of the animal bone recovered reveals that cattle, sheep or goat, and chicken bones are present. All of the butchered bones had been chopped apart by axes or cleavers. We found a large quantity of historic Native American ceramics, many from plain ware bowls. About a dozen Mexican majolica sherds were also present. Flotation samples will be examined for charred plant remains that will allow us to better reconstruct the diet of Presidio residents. The discovery of the pit was exciting because only a few Presidio era features with large artifact samples have been excavated.

The Presidio Blacksmith Shop?

The red adobe brick wall was eventually demolished, knocked down with many of the broken adobe bricks lying in place. Over the top of the wall fall, another east-west wall, this time made from brown adobe bricks, was built against the north-south wall. The brown bricks were probably 19 inches long and 11 inches wide, but later disturbance has made it impossible to determine their actual size. The brown wall and the north-south wall formed the northwest corner of a structure. It is probable that this structure is depicted on the 1862 Fergusson map.

1862 Ferbusson Map of the Presidio

A structure depicted on a portion of the 1862 Fergusson map was locatd during the project. Richard Willey's research indicates that this may be the Presidio blacksmith shop. North is to the left.

What was the structure used for? Artifacts found inside the structure include a pair of manos, one used for food processing and the other reused as a hammerstone; a lap-sized netherstone or anvil used as a working surface for pounding something hard and small; and a three-quarter grooved axe modified for use as a mallet. The netherstone or anvil is especially interesting because there is some evidence that metal items were pounded on it, including a small smudge of copper. We also found some brass scrap metal and pieces of slag. These items are of interest because author Richard Willey, former director of the Flandrau Planetarium, has suggested that the blacksmith shop for the Presidio was located close to where we excavated. This shop was well known for its use of a large meteorite as an anvil. The items we found may indicate that the brown adobe brick structure was part of or close to the blacksmith complex.

Associated with this structure is a set of postholes in the sediments that overlay the Presidio-period trash-filled pit. These postholes were all about 6 to 7 inches in diameter and may represent a porch area or a ramada built up outside the east side of the structure.

Lastly, a pile of large rocks was found along the north side of the brown adobe brick wall. The 1862 map indicates that a small gateway was present at this point for the Calle de la Plaza, which later became known as Ott Street. Why would a large pile of rocks be here? Historian Tom Peterson, of the Arizona Historical Society, has indicated that rocks were often present in street areas, sometimes used to protect the sides of adobe structures from traffic. This seems likely, as several of the rocks were set in slots so that they were upright.


Tucson's Earliest Hotel

The adobe structure was torn down sometime in the 1860s, probably as the area was redeveloped as Tucson's first hotel expanded. In the late 1850s, Robert Phillips began renting rooms out to people. Eventually the Phillips House was sold to Hiram Stevens, a prominent Tucsonan, who remodeled the structure in 1874 and opened it as the Hotel Cosmopolitan. Between 1874 and 1883 he added a curved rock wall to the west side of the structure, probably to help keep traffic away from trees and a garden area. We uncovered a portion of the rock and mortar wall, which was demolished in 1935 when the Orndorff Hotel, as it was known by then, was torn down to put up a parking lot. Traces of the parking lot also were discovered, lying beneath 3 feet of recent fill that helped protect the site.

The Orndorff Hotel pre-1935

The curved rock wall of the Orndorff Hotel is visible in this pre-1935 photograph. Photo courtesy of the Arizona Historical Society, Tucson.

Uncovering a Buried Past

The Center's excavations have illustrated that much more of Tucson's Presidio past survives than had been previously thought. Although basements and underground parking lots have destroyed some areas, many other areas have intact cultural deposits. The discovery of architectural features in the City Hall lawn was particularly exciting, prompting us to wonder if this might be a portion of the west wall of the Presidio. In late April 1998, a panel discussion brought together experts from various fields to examine this topic. After the Center's findings were presented, Tom Peterson of the Arizona Historical Society illustrated how historic photographs provide clues about the past. James Ayres summarized historical archaeology work undertaken in the City of Tucson, beginning with the Tucson Urban Renewal Project in the late 1960s. Thomas Sheridan discussed the role the Tucson Presidio played for people in the area.

Lastly, Armando Elias described the importance of the Presidio for local residents. Opinions differed as to whether the wall uncovered represents the west wall of the Tucson Presidio. To confirm or negate this possibility, we will need to conduct further excavations in the area, to the north and south, to verify whether the wall is continuous and to examine how it was built and how it relates to other structures. One thing is clear: thousands of visitors viewed the excavations. Many were on their way to collect tax forms from the nearby IRS office and happened upon the dig. Classes of school children visited the site. Others came after seeing or reading news stories. Archaeologists provided updates on what was being uncovered, volunteers identified artifacts that were displayed, and literature about Tucson's Presidio was distributed. The community was excited by the opportunity to explore Tucson's long-buried history.



Rediscovering el Presidio de Tucson was funded by the City of Tucson, the Arizona Humanities Council, the Tucson-Pima County Historical Commission, the Tucson Presidio Trust for Historic Preservation, and the Center for Desert Archaeology.

Volunteers performed much of the work. Thanks to Aron Adams, Connie Allen-Bacon, Ruth Amirault, Carter Beach, Jeanette Berry, Georgiana Boyer, Mark Brodbeck, Jason Brownlee, Mike Cook, Ray Coville, Ginny Dean, Don Duey, Steve Farley, Kevin Feig, Ken Fite, Jack Flanders, Bob Flaugher, Elaine Flaugher, Cheri Freeman, Jan Gingold, Howard Greenseth, Toni Griego-Jones, Jennifer Harshmann, Alycia Hayes, Donn Ivey, Foster Knutson, Soni Marvin, Betsey Marshall, Ann McClelland, Laura McFall, Janice McMillen, Mary Lu Moore, Jerryll Moreno, Joe Orabone, Ken Orabone, Robin Owen, Joan Petit-Clair, Dwight Riggs, Lynda Rigoletti, Lauren Sanders, Sally Sanders, Angela Shelley, Itorye Silver, David Smith, Jared Smith, Hector Soza, Mickie Soza, Jean Stern, Margi Sternberg, Donna Tang, Sheri Thompson, Tinake VanZandt, Suzanne Vieta, Jim Vint, Mary Wagner, Lou Washaeur, Mason Washaeur, Mike Washaeur, Josh Watts, Josh Weber, Jennifer Wiedhopf, Pat Wiedhopf, Patty Whitley, Mike Woods, and Pat Young.

Reprinted electronically with permission from Archaeology in Tucson Newsletter.
For more information about archaeology in Tucson visit the Center for Desert Archaeology's web site.