Old houses can have a lot of asbestos. And this one does!
You may have noticed a pattern. Asbestos was used as an insulator for heating systems. It was also used in floor tiles, especially 9" square tiles, I've heard. Maybeck liked fireproof materials since many of his great works fell victim to fires. Especially after the September 1923 Berkeley hills fire, he began to build most of his creations out of stucco with slate or Spanish tile roofs. But he had even used decorative exterior asbestos tiles, similar to our original kitchen floor, before the '23 fire in his masterpiece First Church of Christ, Scientist in Berkeley.
He gave up on redwood siding and cedar shingle roofs long before the mainstream had given them up, which makes sense since he was very interested in hillside homes which are particularly endangered. Stucco became common in the '20s, but redwood clap board siding was common well into the 60s. Cedar shingles as siding seemed to have a resurgence in the 70s and 80s. Lately cedar shingles are required to have a fireproofing chemical added, making them crazy expensive. As a result, they are used mainly in classy restorations as siding and very rarely as actual roofing. The historic restoration that uses cedar shingles for roofing is only for VERY special buildings since it is much more expensive than composition shingles and doesn't last as long.
Back to asbestos -
When people hear something is bad, they assume they're gonna need to tent the house and have haz-mat people carefully remove it from their house. It is bad, but not instant-death bad. Similar to how smoking is bad, but one cigarette, or ten a week for that matter, isn't necessarily going to kill you. Remeber that people who get mesothelioma where inhaling the stuff all the time because they had NO IDEA it was bad. So don't freak out - simply put on a mask, disposable jumpsuit and gloves, water it to keep down the dust as much as possible, and put it into heavy duty plastic bags. But don't take my word for it - look it up yourself if you are concerned.