Fieldwork at John Marsh Home
The John Marsh Home is a small State Park property nestled in the foothills of Mt. Diablo in Contra Costa County. Recently, due to increased residential development in the area as cities like Brentwood continue to grow, a full scale excavation is currently underway on private land along the state park boundary. Due to an historic dam in the area, which traps water and debris, the Marsh Creek has a strong erosional influence on the creek bank and site it contains. The side walls of the creek itself are about 10 to 15 feet tall and provide and intact geologic picture with Holocene soils stretching all the way down to Pleistocene gravels. Excavations at this site have yielded radiocarbon dates ranging from 5410 BP to 9690 BP (two charcoal samples and one soil sample), thus making it one of the oldest sites in the area.
The seasonal flooding of the Marsh Creek and the residential development along the park boundary are slowly eroding the site away. Therefore, it is the duty of State Parks to recover and preserve as much data as possible before these processes consume the site.
Part of this recovery effort included a Volunteer Day on Saturday, February 25th, 2006 at the park. Volunteers from all over the area were invited to come and assist with an archaeological excavation. We could not have asked for a nicer day. Scents of almond blossoms and bruised grass floated through the crisp, cool air as 85 volunteers and archaeologists tromped along the bank of Marsh Creek.
Here in the tiny, water-sculpted canyon below John Marsh’s stone house, these volunteers were oriented to the site by professional archaeologists and Native American monitors from State Parks, CalTrans, and various private CRM firms.
The skill level of each volunteer varied from the entry-level novice to the seasoned professional. Tasks performed at the site included wet screening, shovel excavations and screening, and processing of all the specimens recovered from the screening.
Volunteers at Marsh Creek on February 25, 2006
This volunteer opportunity gave State Parks the chance to educate the public about proper excavation techniques and how to be respectful of the cultural heritage of California. State Parks is greatly indebted to all those who gave a hand to the project’s success. A total of 10 cubic meters of soil was moved from which several thousands of tiny pieces of dietary remains, flaked stone, and obsidian were obtained for future analysis.
Thanks to the efforts of all who attended the weekend excavation, and to all those who gave up more of their time and expertise, State Parks is well on its way to preserving this rare and vanishing resource.
- Kelly Long, Associate State Archaeologist
Photo Captions: A pre-screening meeting is the best way to get everyone on the same page (upper left).
Shoveling provided the material for the actual screens (upper right).
Artifacts are often mixed with the soil, which could call for multiply screenings (lower left).
The recovery stage is key to finding the most important items (lower right).