Comments for Oakland Geology

Comment on Cactus Rock by rbwelch

rbwelch — Mon, 21 Jul 2008 20:16:02 +0000

Because the 1991 fire burned through the Upper Rockridge area, clearing all the structures, there may be photos somewhere of that devastation that may help you find these rocks and outcroppings.

Comment on Oakland Paving by Andrew

Andrew — Sun, 20 Jul 2008 21:38:22 +0000

By the way I should mention that I’ve started a new blog specifically for Oakland sidewalk stamps at oaklandsidewalks.wordpress.com.

Comment on Oakland Paving by Andrew

Andrew — Sun, 20 Jul 2008 21:36:40 +0000

Thanks for that info–I assume you mean Blake in the first sentence, not Anson. Here’s a page from an 1896 state mineralogist’s report with some details, including mention of Blake crushers. Another discussion of old Oakland quarries begins here in the 1893 report.

Comment on Oakland Paving by Bill D.

Bill D. — Sun, 20 Jul 2008 03:34:36 +0000

Oakland paving was the Anson Family. Not sure of the fathers first name. His son Anson Blake took over as president about 1910? Anson’s house is now the house where the University of Califonia president lives in Kensington. the gardens are open to the public weekdays910 acres). I believe the house is cast concrete but it is ironic that the driveway is gravel and not paved. There is a Blake street in El Cerrito named after them.
The Family ran the Blake quarry in Richmond. A cousin Eli Whitney Blake(yes some relation) invented something to do with rock crushing. Their cousin was William Howard Taft.
Bill D.

Comment on Adams Point alluvium by Silver Fox

Silver Fox — Thu, 17 Jul 2008 12:39:06 +0000

It looks like you’d make an excellent ‘grass-roots’ explorationist, tracking down the source of hidden cherts the way you do.

Comment on The labyrinths of Sibley by sheldon white

sheldon white — Tue, 15 Jul 2008 16:31:15 +0000

I used to go up to that quarry in the winter to see if the pond had frozen over; it was fun to slide rocks across and break the ice. I was irritated when someone built the labyrinth, but what the heck.
There’s a lot of interesting stuff to see as you go down that canyon, and if you skirt south into Huckleberry reserve there’s even more intersting remnants of human occupation. There’s some truly ancient old cars in a remarkable state of preservation on the backside of the ridge.

Comment on The labyrinths of Sibley by volcanosummer

volcanosummer — Mon, 14 Jul 2008 11:02:22 +0000

Hey Andrew! This is a very cool site, and I also checked out your About.com page too. I’m going to be exploring that quite a bit in the coming days. I wanted to say thank you for linking my page on your blog. Apparently I’ve been getting a few visitors from you, and it’s always great to have the company! Keep up the good work, and I’ll link to your page after work tomorrow.

Best,
Jess

Comment on The labyrinths of Sibley by Andrew

Andrew — Mon, 14 Jul 2008 02:22:59 +0000

Debby, I’m not yet familiar with the Wildcat Canyon trail, but the stream runs through nonmarine sedimentary rocks of the Orinda Formation on both sides. The openings are probably related to weathering, like you see on Mount Diablo where an outer shell of the rock is hard but underneath it’s less well cemented, so it weathers out in pits. The official geologic name for this kind of formation is tafoni. But as I said, I haven’t walked that trail yet.

Comment on The labyrinths of Sibley by montclairoak

montclairoak — Sun, 13 Jul 2008 21:29:21 +0000

Hi Andrew,

I walked in Tilden a few times, on the Wildcat Gorge trail running below Lake Anza. On the left side, you see some major rocks that look very volcanic with large openings. I’m curious if this is possible?

Thanks,
Debby

Comment on The labyrinths of Sibley by snappingturtle

snappingturtle — Sun, 13 Jul 2008 09:14:36 +0000

that labyrinth has been there at least 20 years, if not longer.