While playing tour guide to summer visitors, Sonoma County people might — but probably don't very often — cruise past the historically priceless though neglected and overgrown Carrillo Adobe on Santa Rosa's Montgomery Drive.
Locals might tell their guests during a drive-by that the crumbly earthen ruins behind the weeds and beneath a carport-type roof are what remains of Santa Rosa's beginnings, its first permanent, non-native residence.
That description is not inaccurate, but a descendent of the founding Carrillos is part of a small corps of people excited and intrigued by evidence that the site of the forlorn, fenced-off adobe was conceived as something immensely more consequential than the ranch home of a family of settlers.
"It looks like there was much more intent there," enthused Larry Carrillo, a Santa Rosa businessman who's dedicated much of his 67 years to preserving and promoting the historical site.
He's fascinated by research suggesting his ancestors in the clan of Maria Ygnacia L?ez de Carrillo did not build the 1837-38 adobe ranchhouse from scratch but erected it partly atop stout, stone foundations that were placed earlier, evidently with a much more substantial building in mind.
A Petaluma archeologist, William Roop, discovered the footings during 2006 excavations required by a developer's proposal to build 140 condominiums on 15 acres that stretch along Santa Rosa Creek and Montgomery Drive from the adobe west to St. Eugene's Cathedral.
To Roop, the origins of the heavy-duty foundation beneath the Carrillo Adobe are clear. He's convinced they were placed by laborers on the orders of Franciscan priests intent on building in Santa Rosa the 22nd and northernmost California mission.
If true, this would mean the place where Santa Rosa was born is the exact spot at which the colonial quest to hold and tame California through a string of missions died.
"We have some riddles here," Larry Carrillo said. He holds that the discovery of the footings and the prospect they were intended to support a mission increase the urgency for Santa Rosa to preserve and highlight at least part of the adobe as a historical treasure.
It's not a new idea that the Franciscans who founded the 20th mission in San Rafael in 1822 and the 21st in Sonoma in 1823 planned also to build a mission in Santa Rosa no later than about 1829 — nearly a decade before the arrival of Maria Carrillo, widowed mother-in-law of Gen. Mariano Vallejo, one of the most powerful men in what was then Mexico's California.
But prior to the discovery of the foundation footings, it was unknown just how close Santa Rosa came to having a mission or exactly where it would have been located.
The historical record of the land near what Maria Carrillo called Rancho Cabeza de Santa Rosa includes accounts of Franciscans from Mission San Rafael Arcangel creating a small outpost or "asistencia" there for converting local Pomos.
"This was definitely trying to become a mission," said Roop, the consulting archeologist. His research leads him to believe the Franciscans did commence construction of an envisioned Mission de Santa Rosa de Lima but abandoned the project before completion of the stone foundation.
"We think what scared them off was the Pomo-Wappo war of 1829 up in Alexander Valley," Roop said.
Whatever forces might have deterred the Franciscans from founding a mission in Santa Rosa, Roop believes the stone footings he and his crew discovered beneath and beside the Carrillo Adobe were intended to support that mission.