BENEATH HISTORIC FLOORS: ARCHAEOLOGICAL INVESTIGATIONS OF THE PETALUMA ADOBE SEISMIC RETROFIT PROJECT Stephen W. Silliman 31 December 1999 BENEATH HISTORIC FLOORS: ARCHAEOLOGICAL INVESTIGATIONS OF THE PETALUMA ADOBE SEISMIC RETROFIT PROJECT Stephen W. Silliman Archaeological Research Facility Department of Anthropology University of California Berkeley, California 31 December 1999 Report submitted to California Department of Parks and Recreation 2505 Port Street West Sacramento, California Abstract The Petaluma Adobe was the residential core of the once-vast Rancho Petaluma, granted to Mariano Guadalupe Vallejo in 1834. Mariano G. Vallejo was one of the most prominent political and military figures in Alta California during the 19th-century, and the Petaluma Adobe was the largest "Monterey Style" adobe built in Northern California. Located in central Sonoma County, the extant Petaluma Adobe, its deteriorated eastern half, and 41 acres of surrounding land are preserved in the Petaluma Adobe State Historic Park. As part of the California State Building Seismic Program, the Petaluma Adobe (CA-Son-363/H) was slated to undergo structural stabilization in 1998 with the placement of steel I-beams and concrete footings at four locations inside the historic structure. Archaeologists from the Archaeological Research Facility at the University of California, Berkeley, were contracted to hand-excavate the four trenches required for the concrete footings. These trenches sampled each of the three standing faces of the extant Petaluma Adobe. Archaeological objectives of this project were (1) to investigate potential protohistoric and prehistoric deposits beneath the structure, (2) to explore the construction history of the Petaluma Adobe, (3) to examine potential room use and material culture of residents at the Petaluma Adobe, and (4) to evaluate the effects of previous renovation efforts on the integrity of 19th- century archaeological materials. Prehistoric lithics were recovered in both pre-construction and fill deposits beneath the room floors. The combination of technological and raw material data generated insight into prehistoric occupation. Coupled with geochemical sourcing of obsidian, obsidian hydration data provided information on site use over time. Sourcing also revealed regionally rare sources in the assemblage. Stratigraphic analysis indicated that a complex series of cut-and-fill episodes characterized the construction of the Petaluma Adobe. The apex of the promontory on which the building sits appears to have been shaved off and the removed soil used to fill the west face. The presence of a buried soil beneath fill deposits in the west face and the appearance of typically non-surface sediments directly beneath floors of the north and south face provided the evidence. In addition, artifacts recovered in the buried soil and the fill deposits of the west face offered clues to material life in the 1830s. However, very few artifacts related unequivocally to mid-19th-century life were found inside the Petaluma Adobe. Old surfaces were visible beneath the modern floor and above fill deposits, but their dates of construction and use were unclear. There may have been several refloorings during the life of the building, and room function may have changed considerably over time. In several cases, 20th-century renovation activities may have been a major factor in the ambiguity of old surfaces. Although limited in scope, archaeological and stratigraphic data addressed the nature and impact of restoration efforts dating to 1910, the 1950s, and 1996. i ii Acknowledgments As with any archaeological project, a number of individuals must be thanked for their efforts in seeing this project take place and reach completion. There is no question that this project ran as smoothly as it did because of the able organizational and archaeological skills brought by Roberta Jewett. She assisted me as co-director and paperwork supervisor throughout most of the project's duration in the field. I would also like to extend gratitude to Kent Lightfoot for his ever-present counsel and support. Moreover, I would like to thank Roberta Jewett and Larry Felton for their insightful and invaluable comments and suggestions on the final report. The excavation team was superb and consisted of a number of individuals. The project occurred in two rounds; the first was a 15-day duration in July, 1998, and the other was an 11-day venture in August, 1998. The first round included the full- and/or part-time work of Colin Bailey, Dale Beevers, Julienne Bernard, Carmen Brown, Bridget Foley, Jonathon Goodrich, Rebecca Graff, Jennifer Johnson, Renate Massing, Michael Miller, Anne Olney, Harmony Plenty, Laura Privett, Brett Rushing, Mark Selverston, Cara Stimpson, Marc Trapani, and Nick Weber. The second round consisted of full- and/or part-time commitments of Dale Beevers, Rachel Braet, Carmen Brown, Agustin Diez Castillo, Jonathon Goodrich, Patricia Hunt-Jones, Craig Kodros, Brett Lloyd, Janet Loftis, Renate Massing, Michael Miller, Heather Mozdean, Michael Newland, Amy Ramsay, Jo Ann Scroggins, Mark Selverston, Tracey Spoon, Tania Stellini, Kathleen Sterling, Cordelia Sutch, Annita Waghorn, Nick Weber, Andrea Yankowski, and Linda Ziegenbein. All preliminary laboratory processing of artifactual material was completed at University of California, Berkeley, in the able hands of Julienne Bernard. I also thank Charity Cuellar and Kimia Rezvani for their tireless assistance with final preparation of the artifact collection for curation. Finally, Thomas Wake and the Zooarchaeology Laboratory at UCLA provided the majority of faunal identifications, and I appreciate their quality and efficiency of work. Sherry Parrish, the MSO of the Archaeological Research Facility (ARF), and Sabrina Maras, Administrative Assistant for the ARF, deserve much recognition for their help with the Petaluma Adobe Seismic Retrofit project contract. They always managed, even under time duress and seemingly endless complications, to provide prompt and efficient assistance to the contract. Without them, the entire project could not have even begun nor come close to completion. I would also like to thank Tim Campbell, the Cultural Resources Officer of the Federated Indians of Graton Rancheria, for his consultation and monitoring during different aspects of the Petaluma Adobe Seismic Retrofit Project. His participation is and has been a necessary and welcome part of all excavations conducted by the University of California, Berkeley in the Petaluma Adobe State Historic Park. I also appreciate the geoarchaeological consultation provided by Jack Meyer of Sonoma State University. My interpretation of the geomorphology beneath the Adobe stems in part from a discussion with him on his one-day visit to the completed excavations. iii Special thanks must be extended to the staff at the Petaluma Adobe State Historic Park for their enthusiasm for archaeology and for their willingness to put up with the constant mess and complications of archaeological excavation. For the seismic retrofit project, those individuals included Ranger Larry Costa, Jerry Mize, Bill Tait, Katie Trapp, John Irwin and Nicole Walcott. I also gratefully acknowledge the access to and permission to reproduce the photographs on file at the Petaluma Adobe State Historic Park. They provide an untold wealth of information. All other "unacknowledged" photographs in this report were taken by the author. Two key people in the California Department of Parks and Recreation must be recognized for their constant support and assistance with the contractual, logistical, and archaeological aspects of the Petaluma Adobe Seismic Retrofit Project: E. Breck Parkman, Regional Archaeologist for the Silverado District, and Larry Felton, Associate State Archaeologist. Without them, this project would never have come together under the time schedule that we had before us. Thanks should also be extended to Glenn Farris and Glenn Burch of the Department of Parks and Recreation for their contributions and guidance. Also, I would like to thank Thomas Winter, Associate Architect, and Bernard Savant, Department of General Services, for their attention to the details of this project and William Andrews and his colleagues from DASSE Design, Inc. for their help in keeping the project on track and for their overall interest in the archaeological work. Finally, I thank Sandy Taugher of the Sacramento office of the California Department of Parks and Recreation for her assistance with accessioning. I would also like to say "thank you" to the public. Visitors to the park have always shown a keen interest in our archaeological work, and I and those who have worked with me are always grateful. We just hope that our answers are as interesting to them as their questions are to us. iv Table of Contents Abstract i Acknowledgments iii Table of Contents v List of Figures ix List of Tables xi List of Appendices xiii Section 1: Introduction 1 Section 2: Historical and Archaeological Background 5 2.1 Historical Overview 5 2.2 The Rancho Petaluma: History and Archaeology 8 2.3 Details of Construction and Use at the Petaluma Adobe 12 Section 3: Archaeological Research Design 21 3.1 Locations and Dimensions of Excavation Trenches 21 3.2 Excavation Techniques 23 Section 4: Results: Stratigraphy 27 4.1 Trench 1 28 4.2 Trench 2 31 4.3 Trench 3 39 4.4 Trench 4 48 4.5 Summary 54 v Section 5: Results: Material Remains 57 5.1 Trench 1 59 5.1.1 Ceramics 59 5.1.2 Glass 59 5.1.3 Beads 59 5.1.4 Metal