Horseshoe Canyon is a small, but dramatic gorge cut into the Oakland hills between Holy Names College, Merritt College and Mills College. The waterway in it is Horseshoe Creek, a branch of Lion (Leona) Creek. Today the canyon is preserved within Leona Heights Park, but in Oakland’s oldest days it was first logged, then mined and quarried. Great stumps remain from the aboriginal San Antonio redwood grove, the mine tailings stain the creek below the old sulfur mine, and the quarry scar sits in the undeveloped scrub at the north end of Merritt College.
This stout concrete structure once braced one of several aerial tramways, whose steel cables carried large buckets of ore and rock from a rail line coming down from the heights to another railhead near the mouth of Horseshoe Creek, in Laundry Farm Canyon. You can visit it by walking down from the Merritt College campus or up from the end of McDonell Avenue near the sulfur mine. This photo was taken in 2003, and the art has undoubtedly been painted over since then with something more contemporary. (click full size)
See more detail about this area’s history in Steven Mix’s History of Laundry Farm Canyon page.
Oakland Geology 
13 February 2012 at 9:53 pm
Steve Mix’s fabulous old prodigy.net map looks to be gone, but replaced by a far better one here: https://picasaweb.google.com/106313661130472975881/OaklandHistory#5652732157676157330
See also the relevant listing in this exhaustive catalog of historic quarries:
http://quarriesandbeyond.org/states/ca/quarry_photo/ca-alameda_photos.html#list_of_quarries
“Leona Heights Quarry; E. B. & A. L. Stone Company, 900 Broadway, Oakland, owner; G. H. Luchs, superintendent. It was formerly the California Improvement Company’ quarry. It is on Laundry Farm, on the summit of a prominent ridge, one mile north of Mills College. The rock is a fine-grained basalt, and is used for macadam and concrete. The quarry face is about 125 feet high. Two gravity trams, one 2500 feet long and the other 1200 feet, take the rock from the quarry to the crusher at the termini of the railroads, both narrow and broad gauge. About 300 yards a day are rushed by two Gates crushers. Electricity is used for power. thirty-five men are at work in the quarry.”
14 February 2012 at 11:39 am
Thanks for tracking that down!
By the way, Peggy and Pat Perazzo, the creators of quarriesandbeyond, live just over the hill and were on hand for my quarry walk last weekend.
6 July 2012 at 2:07 pm
Belfast Ave. was a great place to live. Full of “Baby boomers”. For first 19 yrs. lived in the hills. Places like “Cement Ft.” the tram works near “Devils Punchbowl” Or “Rock Ft.” where great piles of rocks were in front of small draws on the hill side??? “Do not go near the mines” our folks would say, right! The Hotel mine was right up the hill above the “Tunnel” which housed a conveyor down to Laundry farm bunker. As far as I know a couple of my friends and I were the last people in the Stauffer mine when a rain storm opened an entrance behind the newly built Leona Lodge.
Any Pics of the trams or the tunnel in action? Mr. Robiano, about 90 in 1960, talked about the haze over the hills from a mine fire that burned for years! M P
6 July 2012 at 4:54 pm
The place to check for old photos is the History Room at the main library.
Now you make we want to poke around the hills there.
25 January 2013 at 1:01 pm
@ Maury:
Cool account about the fire. I’ve also heard that the hillside is littered with old shafts. I could imagine that a fire could smolder for quite some time in old complex like that. I wonder when the fire was, maybe there is some newspaper accounts of it.
16 February 2021 at 9:19 am
Thank you for all this info, I have lived in Oakland all my 75 yrs and have always been curious about the Leona area especially.
17 April 2022 at 11:08 am
Like Maury says cement fort (the huge open pit quarry) was one of the places we frequented while growing up. Paul Robiano who kept bees on Mountain blvd in the 50’s and 60’s told me the story of a foggy day when the buckets of gravel coming down the hill got scraped off on a support years ago. about 1/2 mile from Mills College. Me and Maury grew up discovering mines and having a look inside up where the Martinez’ house was atop mcdonnell st. I surely miss Captain Maury but a grand childhood we had. jim Rait
17 April 2022 at 11:15 am
I must correct my comment. The open pit was Devils Punchbowl and the foundation was Cement Fort. The Tunnel was a favorite spot where us kids played and we made up stories about families of mountain lions that lived there. I’ve taken my boys hiking all over there. Lots of memories. jim
17 April 2022 at 10:47 pm
You mean Maury Poise, who commented here ten years ago?
My condolences.