On one side of the presumed foundation, the block excavation revealed a large bone feature that extended for approximately 6 square meters. The feature contained a large number of animal bones including both cattle and fish, nails, shellfish, obsidian flakes and tools, groundstones, fire-cracked rock, burned wood, and other items. These remains are unequivocal evidence of residential and perhaps work debris left by the native people during Vallejo's occupation of the Petaluma Adobe area. However, a question still remains as to where exactly the native residenti al structures were and how they looked. Further excavation revealed that the presumed cobble foundation may not be a foundation at all, looking m ore like a natural concentration of stream-like deposits.
Future investigation is necessary before offering a final conclusion.
In summary, substantial evidence has been recovered by the UC-Berkeley archaeological team that will offer significant insights into the Petaluma Adobe State Historic Park. So little is known about the Native Americans who worked at th e Rancho Petaluma, in large part because of the sparse historical documentation. Thankfully, archaeology is able to cast new light on those dark spaces in the history of 19th century Mexican-Californian ranchos. Most importantly, the work being conducte d at the Petaluma Adobe State Historic Park has direct historical and archaeological ties to other California state parks such as the Sonoma Mission and Fort Ross State Historic Park.