detail of flyer 1

Cactus Rock is a rock formation in Upper Rockridge. It is located at 6160 Acacia Avenue, a house with driveway access off of Alpine Terrace next to Locarno Path. According to a 1910 flyer from Laymance Real Estate, which developed the area, Cactus Rock inspired their name for the development.

Oakland Geology described the rock as a knocker of the Franciscan Complex, local geologists' slang for a small body of bedrock, surrounded by a matrix of softer rocks, that protrudes from the ground surface in areas of melange.

photo CC BY-SA 2.0 by rbotman01photo CC BY-SA 2.0 by rbotman01photo CC BY-SA 2.0 by rbotman01

Rock Ridge

There is a poorly sourced account, echoed in The Story of St. Theresa Parish, that the rock which inspired the "Rockridge" name was located at Glenbrook and Bowling on the Livermore estate, which was later dynamited to make way for more homes. 2 It shows the same photo of Cactus Rock shown on the cover of Images of America: Rockridge from Arcadia Publishing. The former dates the photo c.1890, the latter c.1912.

As noted in the 2012 OaklandNorth article, the name Rock Ridge appears in the area at least as back as 1878 to label the highlands north of the Rockridge branch of Glen Echo Creek where the Livermore estate sat. That article also mentions that Cactus Rock was "ultimately blasted to make room for further development." 3 However, although some rocks were certainly removed to aid home building, Cactus Rock was enclosed in an especially large lot and remains looking as it did a century ago.

Cactus Rock 21878 Thompson and West map excerpt

Links and References

  1. G4364 O2 2R62 1910 L3 UC Berkeley Collections
  2. The Story of St. Theresa Parish page 5 (2001)
  3. Hills covered in beautiful homes OaklandNorth May 15, 2012