Current Research: USA - Pacific Northwest
Reported by Robert Cromwell bob_cromwell@nps.gov
(Spring 2008 SHA Newsletter 40[4])
Oregon
Oswego Iron Furnace (35CL297) (submitted by Rick Minor, Heritage Research Associates, and Susanna Kuo, Oswego Heritage Council):
The Oswego Iron Furnace, the first iron furnace on the Pacific coast of North America, was constructed at the confluence of Sucker (today’s Oswego) Creek and the Willamette River in the small town of Oswego (today’s Lake Oswego), Oregon, in 1866 and 1867. Listed on the National Register of Historic Places in 1974, the masonry stack from the historic furnace stands in the city’s George Rogers Park and is the only surviving charcoal furnace west of the Rocky Mountains.
Modeled after the furnace at Lime Rock, Connecticut, the Oswego Iron Furnace was constructed of hewn basalt blocks and measures 32 ft. square at the base, 34 ft. in height, and 26 ft. square at the top. The foundation of the furnace was said to extend 12 ft. below ground to bedrock. The furnace is shaped like a truncated pyramid. Gothic arches of common brick provide access to the smelting chamber on each side. The largest arch, called the casting arch, is where iron was tapped from the furnace. The three smaller arches are where the “tuyeres” or blast pipes were inserted through the wall of the smelting chamber. The Oswego Iron Furnace was a “ten-ton stack,” so called because it could produce 10 tons of iron in one day. To enlarge its capacity, the stack was raised 10 feet in the winter of 1878-1879.
Over the course of its operation, the Oswego Iron Furnace was owned by three different companies (Oregon Iron Company, Oswego Iron Company, Oregon Iron & Steel Company). It produced pig iron marketed under the name “Oregon Iron” on an intermittent basis between 1867 and 1885. After the furnace was blown out for the last time in 1885, the associated wooden buildings and other features were demolished, leaving the furnace’s masonry stack and a nearby stone retaining wall as the only above ground remnants of this historic iron works.
In advance of proposed improvements to George Rogers Park, the city of Lake Oswego sponsored an archaeological survey in 2003, followed by archaeological testing in 2004. These studies confirmed that archaeological deposits and historical artifacts associated with the historic iron works are present along the edge of the river terrace southeast of the furnace. Monitoring during construction of park improvements in 2005 resulted in the collection of artifacts that included more than a hundred (mostly fragmentary) firebricks from the historic furnace.
No stabilization work has ever been conducted on the masonry stack. In 2005 the city of Lake Oswego was awarded a Save America’s Treasures grant from the National Park Service to obtain information needed to prepare plans and specifications for the future stabilization of the furnace. One requirement of this study was to expose a portion of the furnace’s foundation to allow a structural engineer to examine the configuration and condition of the stonework.
To ensure that archaeological deposits were not disturbed or destroyed during the foundation exposure, controlled excavations using standard archaeological techniques were undertaken. Trenches were excavated through the east tuyere arch and the casting arch, exposing portions of the hearth and crucible in the center of the furnace. The trench deposits consisted of sand containing variable amounts of rubble in the form of angular basalt dressing stone fragments and whole and fragmentary firebricks and common bricks. This debris apparently represents materials discarded out the arch openings when the hearth and crucible were periodically rebuilt.
At the junction of the two trenches, the excavations exposed a quarter of the crucible, the circular firebrick reservoir where molten iron collects in the middle of the furnace. The crucible rests on top of a firebrick hearth, which measures 12 by 14 ft. and 33 in. high. The section of the curving crucible wall that was exposed consisted of five courses of wedge-shaped firebricks and was filled with solidified iron bonded to the bricks.
The Oswego Iron Furnace.
The excavation also exposed half of the forehearth in the center of the casting arch. This is a channel through the crucible wall where molten iron collects behind the damstone. The position of the missing damstone was confirmed by the discovery of the remnant of the iron backstay that would have braced the wall next to the hearth opening. When the furnace was tapped, molten iron was channeled to the casting house through a metal runner set against the damstone below the tap hole. A large lump of iron directly in front of the forehearth is probably a spill that occurred during tapping.
The excavation revealed that the foundation is not a single monolithic platform, but a two-tiered structure. The bottom is a large platform of dry-laid basalt 36 ft. square and approximately 8 ft. high. Centered on top of this foundation is the firebrick hearth, which is surrounded by four mortared footings that support the piers of the furnace. These diamond-shaped footings and the hearth are approximately 33 in. high. The space between the footings, which lies under the arches, is filled with sand. This would have been easy to remove when the hearth needed repairs.
A backhoe was used to extend excavation in the portion of the east arch trench outside the masonry stack to expose a portion of the foundation all the way down to bedrock. The bottom of the masonry at this location was reached about 10.5 ft. below the present ground surface. This depth is less than the 12 feet cited in an historical account as the depth of the foundation, but it is likely that the bedrock underlying the site is uneven and that other sides of the foundation may rest on deeper bedrock.
The face of the foundation exposed in the trench showed that it is comprised of dry-laid basalt boulders with smaller chink stones filling voids around the larger rocks. Similar loose angular basalt rock was found at the bottom of the trenches in the interior of the foundation, underlying the sand associated with the working floor inside the furnace. The loose dry-laid boulders composing the foundation contrast with the neatly dressed and mortared ashlar masonry of the furnace’s superstructure.
An enigmatic feature encountered during the furnace investigations is a brickwalled chute topped by cast-iron plates. This feature was first discovered in 2005 when a concrete reflecting pool constructed during the 1950s was removed from in front of the casting arch. Facing of the sides of the hole from the pool removal exposed the feature and established that it extended from the west side of the excavation to the midpoint of the casting arch. The same kind of covered channels were encountered again in 2006. They were discovered running across the top of the dry-stone foundation in the east tuyere arch and in the casting arch. The function of this feature, which appears to extend toward the center and underneath the bottom of the hearth, remains unknown.
The firebrick inwall of the furnace is entirely missing and early photographs indicate that it was lost or deliberately removed not long after the furnace shut down in 1885. By far the most common artifacts found are firebricks, with over 400 mostly fragmentary specimens recovered during the series of investigations. Identification of the 18 brands represented has relied primarily on research by National Park Service archaeologist Karl Gurcke. Thirteen brands are from companies in England or Scotland: COWEN; FELL; GARTCRAIG; HARRIS & PEARSON; HEATHERKNOWE, HICKMAN & CO.; J. & M. CRAIG, KILMARNOCK; JMcNS & CO.; HEATHERKNOWE, PERRENS & HARRISON; R. BROWN & SON, PAISLEY; RUFFORD; STARWORKS; GLENBOIG; and T CARR.
Three brands are from companies in the United States: LACLEDE; PALMER NEWTON, ALBANY; and WATSONS/P. AMBOY, N.J. Two brands are unidentified: A & CO. and a partial brand consisting of the letters HI…/ST… in a frog (different from the HICKMAN & CO. brand). Most of these brands have been previously documented by Karl Gurcke and others. Assistance is sought in identifying the two unidentified brands, as well as in documenting the WATSONS brand from New Jersey, about which information has not yet been found.
The series of archaeological investigations undertaken in George Rogers Park has resulted in the collection of a considerable amount of new information about the historic iron works in Lake Oswego. Analysis of the cultural materials recovered during the structural foundation explorations in 2006 is still underway. Together, the new information obtained regarding construction details and the cultural materials recovered will contribute new perspectives on the historic Oswego Iron Furnace as well as similar furnaces in Connecticut.
Washington
Fort Vancouver National Historic Site, Hudson’s Bay Company Gardens (submitted by Elaine Dorset, Portland State University Department of Anthropology):
The 2006 Public Archaeology Field School at Fort Vancouver brought together the resources of Portland State University, Washington State University-Vancouver, the National Park Service (NPS), the Vancouver National Historic Trust, and the Pacific Northwest Cooperative Ecosystem Studies Unit (PNW CESU) to investigate the Hudson’s Bay Company’s (HBC) Formal Garden at Fort Vancouver National Historic Site. The garden was, and is, a unique space and place, both in the 19th century, at the height of its influence on the HBC’s fur trade enterprise in the Pacific Northwest, and in the 21st century, as an archaeological site.
Fort Vancouver National Historic Site commemorates the HBC Fort Vancouver, (1829-1860), the administrative depot of the HBC’s Columbia Department. At the height of the North American fur trade, and the beginnings of American settlement of the Pacific coast, this British colonial settlement had both an incredible array of ethnic diversity represented in its workforce, and a high degree of development of early industrial and agricultural networks. It was also the site where many of the most famous personages associated with the European- American development of the Pacific Northwest were headquartered, such as HBC Chief Factor Dr. John McLoughlin, commonly known as the “Father of Oregon.”
The site celebrated its 60th anniversary of archaeological exploration in 2007 and represents one of the most significant historical archaeological sites in the Pacific Northwest. Various components of the HBC occupation have been archaeologically explored since 1947, including the 29 structures within the fort, its palisade wall, and the socially segregated Servant’s Village, located ¼ mile west of the main fort complex.
One area that had yet to be systematically surveyed for archaeological resources was the two acre area of the HBC gardens, located on the north side of the fort complex. According to historical records, Dr. McLoughlin’s Garden, (as it was called by 19th century inhabitants), fulfilled several needs for the HBC. The majority of the garden was planted in vegetables, providing nutrition for upper class employees. Also, the garden contained the first successful fruit orchard in the Pacific Northwest. Herbs were grown to medicinally treat the puzzling and constant fevers and other ailments. The garden also served to reinforce the socio-economic classes of the HBC employees, being tended to by the multi-ethnic “Servants” who resided outside of the fort walls, for the greatest benefit of the mostly British and Scottish male “Gentlemen” who resided within the fort. And finally, the garden’s wide paths and abundant plants and flowers from around the globe manifested a British imperialistic device, employing the latest experimental techniques and providing new and valuable botanical information to the British Empire.
Fort Vancouver’s garden is also unique as an archaeological site. It is one of a very few garden sites that have been investigated in the Pacific Northwest. The scope of this investigation surpasses any of the other known garden archaeology projects.
A team of archaeologists spent the summers of 2005 and 2006 excavating this garden space. The 23-member team was comprised of primarily Portland State University (PSU) and Washington State University undergraduate and graduate students, and led by Dr. Douglas C. Wilson, Vancouver National Historic Reserve Archaeologist.
The field school provides students with an intense, highly varied, hands-on experience, vital to their pursuit of a career in archaeology. In 2006, students were exposed to forms of specialized sampling specifically related to the analysis of botanical remains. They also had the opportunity to perform laboratory work at an on-site facility and receive training in survey, remote sensing (ground penetrating radar and magnetometry) and GIS equipment and techniques, providing a well-rounded exposure to archaeological research.
Excavation in progress of a probable WWI-era dry well associated
with the activities of the U.S. Army’s Spruce Production Division’s Vancouver Cut Up Plant operations, with the reconstructed
bastion of HBC Fort Vancouver in the background.
Analysis of the two years worth of excavations is still ongoing, but preliminary results can be discussed. Remote sensing data and a visible surface vegetation anomaly provided evidence of a large shaft feature, just north of the reconstructed Fort Vancouver palisade, which was interpreted as a possible HBC-era well specific to the garden area. Excavations in 2005 revealed the top five feet of fill of this feature was filled with World War I-era U.S. Army trash, the results of the U.S. Army’s Spruce Production Division’s Vancouver Cut Up Plant (ca. 1917-1923). Further excavations in 2006 necessitated the use of hydraulic shoring to continue excavations safely, finding only more WWI-era deposits, bottoming out at just over 7 ft. below surface. It is now interpreted that this large shaft feature is a WWI era dry well, used by the tent encampment of the Spruce Production Division.
Excavations to the northeast of the garden very likely established the location of one of the HBC-era root houses. Ongoing paleobotanical analysis (palynology and phytolith analysis) should provide valuable information to support this hypothesis, and determine what types of crops were being stored in the roothouse.
Additional excavation trenches were placed throughout the garden area in an attempt to identify boundaries between paths and planting beds. This would allow the NPS to extrapolate the layout of the garden. Unfortunately, these boundaries were not obvious during excavation. It is hoped that the results of the ongoing paleobotanical analysis will show a spatial relationship which differentiates between these two uses of the landscape, and may provide evidence of segregated crop beds with many various exotic plant species that are mentioned in the historic record.
A master’s thesis is pending which will provide data and conclusions based on the excavations and artifact analysis, including pollen and phytolith analysis. The recovered artifacts are curated at Fort Vancouver National Historic Site.
