The hunt for Rockridge Rock

The Rockridge neighborhood has migrated over the years. Today Rockridge centers around the Rockridge BART station, in the valley of Temescal Creek. But a hundred years ago, Rock Ridge referred to the highlands between that valley and the one to the southeast, through which the Rockridge branch of Temescal Creek flows (in the Claremont Country Club golf course and upstream along Broadway Terrace). The ridge was supposedly named by the Livermores, who put their mansion on it amid their 600 acres of land making up today’s Upper Rockridge neighborhood.

There was a famous rock somewhere up there that became a popular picnic site in the late 1800s. Photos show it as being blocky, massive stone, maybe 10 meters in height and greater in width, big enough for dozens of people to stand on for their portrait. Lately I’ve been trying to find it. Old maps don’t show it, but Jonathan Chester’s excellent book Berkeley Rocks has some information. He claims that the developers of the area named the rock itself Rock Ridge and encouraged the public to visit it. Today I found an article from the Call of March 12, 1910 about the area:

“Hundreds of people went out to Rock Ridge park, during the week, to enjoy the inspiration found in the budding trees and flowers awakened by the first touch of spring. The visitors found that the opening of streets, avenues, walks and drives through the famous old Rock Ridge picnic grounds has facilitated access to the points of interest. Those who have known best and enjoyed most the peculiar charm of the place were delighted to find that the plans of the owners of the Rock Ridge property in laying out the tract with wide streets and avenues and ample lots have preserved the distinguishing features unimpaired. The army of admirers of Rock Ridge property has received new recruits every day. A number of sales of lots, were made during the week to people who will build immediately fine homes on their grounds. The street work is being rushed. The planting of flowers and shrubs along the cement curb line is also receiving attention from a force of [men].”

The story suggests that while the “famous old” picnic grounds were wiped out by subdivision, “the plans of the owners . . . preserved the distinguishing features.” From this evidence and that cited by Chester, the rock was widely known and hard to miss. Therefore I can’t understand why Chester thinks that the site of the rock is on Glenbrook Drive at the corner of Bowling Drive:

It’s a beautiful outcrop, nicely integrated into the two properties that own it, but no way is that the Rock of Rockridge. It’s the wrong size, the wrong shape and the wrong rock type. And the Call story at least hints that the Rock was “unimpaired” as of 1910.

I think that Chester may not have looked hard enough. I have found at least two other candidates for the Rock, but there is still some ground to cover and many places for rocks, even huge ones, to hide.

25 Responses to “The hunt for Rockridge Rock”

  1. Piedmont Rick Says:

    I’m looking forward to the next chapter. With the nearby mine, isn’t there a good chance the Rock was blasted apart at some point?

  2. Piedmont Rick Says:

    This satellite photo in Google Maps shows an odd formation on what I believe you’ve identified as Rock Ridge, between the Claremont Country Club and the cemetery. See Placemark 1.

    It’s probably an old foundation or some landscaping materials, but I’m curious if you’ve been in the area.,-122.238755&spn=0.001936,0.004066&t=h&z=19&msid=102562663997014770109.000451b98a55d9a707763

  3. Andrew Says:

    I assume you’re talking about the shopping center quarry? That’s half a mile away. No, removing a rock the size of Rockridge Rock is a difficult, expensive operation that wouldn’t yield enough buildable land to be worth the trouble, especially when distinctive natural features were considered an asset. Consider that during the nineteen-oughts, Berkeley was developing the Thousand Oaks, which cherished all the rocks. And in Upper Rockridge, you have the Margarido boulder, which might be a candidate for the Rock (but I don’t think so). That dates from the same time, to judge from the style of the house. That rock is what Rockridge Rock looks like in photos, a massive stone of some sort, whereas the rock on Glenbrook is strongly layered chert.

    The feature you saw in the photos is across the creek from Rock Ridge. I’m sure that’s a rubble pile of some sort, like others you can see on the property. The owners of the land, which I assume is the country club, are developing it right now. It’s private land, and I haven’t been trespassing. I’ve been scrutinizing it from a distance, in case there’s a lot of bedrock, but I didn’t see anything. Maybe the cemetery people or someone who’s a country club member will speak up. The land would make decent home sites, except that they’d have to put up high fences to keep golf balls out.

  4. Piedmont Rick Says:

    Thanks for the orientation. Yup, I was thinking of the quarry behind the mall at Pleasant Valley @ Broadway (apparently known as the Bilger Quarry – see the Rockridge book reference below).

    I spent some time with the Oakland Museum of California’s online collection of old photographs and documents, looking through real estate tract advertisements for anything that would provide a clue, without luck.

    Elsewhere on their site I did find their Guide to Bay Area Creeks, which helped me learn about the watershed of Temescal Creek.

    Amazon has enabled the ‘search inside’ function for the book Rockridge by Robin and Tom Wolf. The cover photo is a picture of what the authors identify as Cactus Rock, which the notes inside describe as being on the H.P. Livermore estate. A note on page 47 of the book places Cactus Rock on Acacia Ave.

    A little ‘walking around’ with Google Street View reveals a sizable rock formation behind or adjacent to what Google identifies as 6128 Acacia Ave. The bird’s eye view in Microsoft Live has a nice perspective aerial photo – that rock might even be 10 meters high.

    I’ve added the Margarido boulder, Glenbrook rock, and possible Cactus Rock to the Google map (link above).

  5. Andrew Says:

    Good work–you’ve certainly taken the bit in your teeth. The one on Acacia is my favorite candidate at the moment. I need to study a hard copy of the book, because so much of it is locked off and the photos aren’t very good online. I’ve poked through it online before but never got as far as page 47.

    By the way, the story that the Rock was dynamited seems to come from the memoir of Horatio Livermore’s daughter Mattie. It boggles me that they bothered, assuming she’s correct, but then real-estate greed has a long pedigree.

  6. Allan Says:

    I’m enjoying your survey of Rockridge Rocks – I took a few photos of the rocks in the empty lot at 6067 Contra Costa Rd. If you would like me to send them to you – send me an e-mail.

    Contra Costa Rd

  7. Andrew Says:

    Allan, just write to me at

  8. Tom Smith Says:

    Here is an address for a most beautiful Rockridge rock – so big in the front yard that it blocks the house.
    5855 Margarido Dr

    I’m enjoying your posts. Thanks,

  9. Andrew Says:

    Thanks, Tom. I mentioned that house back in April.

  10. rob Says:

    how about the corner of linconshire and westminister?,-122.239937&ll=37.84125,-122.240008&spn=0.005096,0.011694&z=18&panoid=MKmixjsmpOGgnJO9-IjEgg

    looks pretty big… cant tell if the house is built on op of it. doesnt look 10 meters tall though.

  11. Andrew Says:

    You know what? That’s the rock I misidentified as being on Bowling Drive. I’d better go make a correction.

  12. rob Says:

    actually there is one on bowling and glenbrook, which is essentially up the street. maybe you have both of them though, because the house shown in the one picture is definitely on glenbrook.

  13. rob Says:

    nevermind, i see :) it was another post that misidentified the rock.

  14. Surfing in the heat « FutureOakland Says:

    […] is one of the defining features of our hilly landscape. Inspired by a post, I went and found the Rock Ridge Rock a few weeks ago: my mother remembered it from when we lived in the neighborhood a decade ago. […]

  15. Lisa Says:

    I love a mystery and am wondering if the August 27 post is the answer to the puzzle? If not, have you seen the rock formation under a house that’s entry is on Ostrander and backyard borders Broadway Terrace (the lower section below the green belt). It is situated across from the Village Market, Claremont Country Club and Mountain View Cemetery. They are currently working on the house so you can see just how far the mass goes under the foundation. Enormous and just amazing!

  16. Andrew Says:

    Lisa, that post is referring to Cactus Rock, which is one of the possible answers.

    There is quite a lot of bedrock above that side of Broadway Terrace. I think I know the house you mean, and now you make me want to walk up there again–it’s been a while. But if you consider that rock a candidate too, then you can see why it’s harder than it seems to confirm the actual outcrop that was the original Rock Ridge.

  17. Stuart Says:

    I have been on top of this rock, believe me, it exists and it is very large indeed. Unfortunately, i can’t remember where it is (yet).

    When I moved here 4 years ago I was escorted by some people to this rock outcropping. It was covered in a bit of graffiti and broken glass, but it’s there. It comes out of a hill and at the highest part, i would say it is well over 10m. They had a name for it, which i can’t seem to recall either. It was in the lower of the rockridge hills close to berkeley.

    It is on private property; we had to trespass through someone’s yard to get to it. There was no public parking. I am still researching and noodling through google maps trying to locate it again. That is how I came across this blog entry.

  18. Dan Scannell Says:

    The Oakland Main Museum’ Oakland History Room has a “Rockridge” folder w/ historic pics. One shows what I think is Cactus Rock on Acacia surrounded by people circa 1910. I can’t post the pic here, but did take a pic w/ my phone and can email that to anyone who might be interested – just send me a note at

  19. Andrew Says:

    Dan, is it this photo that was made into a book cover?

  20. rob Says:

    i came across this today, but i’m not sure it’s a new source of information. the claim is that the rock at glenbrook and bowling is the rock but it has been destroyed by the establishment of the neighborhood.

    but then this article goes on to claim that the rock is cactus rock… which is probably 200 meters or more from the rocks at glenbrook and bowling…

    still muddled by the mists of time.

    [Thanks for both. So much writing today relies on secondary sources that I don’t trust any of it, sad to say. For instance, Horatio Livermore may have been eccentric, but would even he have blown up an enormous landmark like Rockridge Rock? Why bother? — Andrew]

  21. artisancrafts Says:

    After reviewing the sites on google earth using the timeline feature, I was able to survey upper Rockridge from aerial photos from 1993. That area was ravished by the great fire and almost every geological anomaly was exposed.
    I think that the hill above the stairway at 6160 Acacia Ave is the best location for the “Rock”.
    Trolley and other public conveyances went up both Broadway and Broadway Terrace if I’m not mistaken, and one must never forget that people were far hardier when it came to hiking then.,-122.24014&z=18&t=h

  22. rob Says:

    one thing i noticed the other day is that there’s an enormous mural on the side of the red oaks realty office (51st and broadway) that faces the parking lot of broadway pet hospital. it appears to be a scene looking up the hill, possibly from the area where college and broadway meet. the stone gates at rockridge blvd. are visible, as are the claremont hotel, a few wooden houses and the creek that runs through the country club. mostly though, the hill is just a hill. i wonder if there is a photograph that this was adapted from, and if the rock is visible in that photograph.

  23. OUP Walk: Rockridge Ramble « Oakland Urban Paths Says:

    […] At the top of the Locarno Path on Apline, I was told by one of our walkers that were indeed near the fabled Rockridge Rock. The exact location of said rock has been a topic of discussion on Andrew Alden’s blog. […]

  24. 52walks Says:

    […] information: About the hunt for the original “Rock Ridge” and the Margarido boulder from the Oakland Geology blog. A four-mile walk that starts at […]

  25. rob Says:

    well i happened to meet the artist who painted the mural one day. he told me that he found the image in the california museum’s archives. here it is in their online collection:

    can’t see too many rocks… oh well.

    [That knocker is the 5855 Margarido rock! — Andrew]

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