Recently a mystery has been solved that had perplexed my Cliff House history friends.

Yes, I have Cliff House history friends. (My wife thinks it’s funny too.) There’s about a dozen of us. We occasionally have lunch. We email each other when a historic photo or tidbit is unearthed — perhaps someone gets a postcard on eBay that depicts a rare oceanside view or finds an old newspaper article on Alaskan sled dogs visiting the Cliff House (it happened). Considering the highly focused subject of interest, the Cliff House historians come from a variety of backgrounds. We have photograph collectors, architectural historians, current and former National Park Service rangers, restaurateurs, and a former employee of Sutro Baths. Each brings a slightly different kind of expertise and knowledge.

Really, the group is interested in the entire “Sutro District”: the Cliff House, the heights above it, and the cove to the north where the magnificent Sutro Baths burned down. Prussian-born Adolph Sutro was a San Francisco mayor and philanthropist, and at one time he owned a good chunk of the real estate in San Francisco. He turned the Cliff House from a slightly disreputable roadhouse into a Victorian castle, created a personal estate and gardens above, and with Sutro Baths built a huge glass-roofed complex with swimming pools and curiosities for the public. Unhappy with the Southern Pacific’s monopoly on city transportation, Sutro built his own transit line to deliver people to his pleasure grounds.

Photo: Courtesy Bob Schlesinger Collection

Back to the mystery. In some old photos a curious inscription of two letters can be seen in the gables of the original Cliff House building wings. At first it looked like “C.S.” Were they the initials of an operator or owner? They didn’t correspond with the various names we could all associate with the venerable cliff side institution. On closer inspection, the first letter seemed to be an “L” instead of a “C,” but that still didn’t match up with any known person.

John Martini, former NPS ranger, found the answer in the July 2, 1888 edition of the Daily Alta California newspaper. An article about the opening of Sutro’s railroad line to the cliff mentioned in passing that the inscribed letters stood for the Latin locus sigilli. This term, often shortened to “L.S.,” refers to the spot on a legal contract where an official seal was to be applied. Locus sigilli literally means “place of the seal.”

All along, the two letters were nothing more than a legal pun. One of the Cliff House’s primary attractions had been the opportunity to watch the sea lions that lazed on the rocks below. If you don’t mind being loose with your marine mammal terminology (seals and sea lions are different creatures), the Cliff House was definitely the “place of the seal.”

According to a Bret Harte short story, “Bohemian Days in San Francisco,” the Cliff House inscribed “L.S.” on the bar’s decanters, wine-glasses and tumblers as well.

I would never advocate graffiti, especially on a piece of federal property (the Cliff House is part of the Golden Gate National Recreation Area), but I’d really love to have this delightful bit of 19th-century fun return. Time to rally the troops; perhaps the Cliff House historians can make it happen.

Some of the Cliff House historians have their own spaces on the web:

Gary Stark’s Cliff House Project

Zoe Heimdal’s San Francisco Memories Check out the studio photo collection!

Trivia answer: Last column, we asked, “What was Playland called in the early 1920s before the Whitneys took over?” The answer is “Chutes at the Beach,” after the popular water ride that was one of the first large attractions built on the site.

New trivia question: What heavyweight boxing champion trained at the Seal Rock House (Balboa and La Playa streets) in 1910?

Woody LaBounty is the founder of the Western Neighborhoods Project, a nonprofit organization dedicated to the history of western San Francisco, and the author of “Carville-by-the-Sea: San Francisco’s Streetcar Suburb.”