Sunset Line and Twine building, Petaluma

Local history is not necessarily a topic that draws a stadium full of fans, but there is interest.

Since we started running “Mystery Photos” last week from the Sonoma State University digital archives, that interest has been building.

“We have had almost 400 visits to the digital collections in September, and that’s definitely above average,” said Lynn Prime, Digital Projects Librarian at SSU.

So far, Prime has digitalized some 300 images from an archive of roughly 850 photos, taken during the ’70s by students in the college‚Äôs historical preservation course. Details on the pictures are generally skimpy.

Today’s photo — Mystery Photo No. 6, Sunset Line and Twine building, Petaluma (ID# carpssu_139) — already has been identified but more background would be helpful.

“The photo was taken in 1976 by Steve Knutson. We know it was a silk mill that became Sunset Line and Twine in the 1930s. We’re mostly interested in any stories about the varied history of this building,” Prime said.

You can post your information and comments here, or contact Prime directly at or (707) 664-4025. For more information on the North Bay Historic Preservation Digital Collection, and more photographs, visit