Oakland Geology

As promised, here’s a look at Sugarloaf (a/k/a 1175) Hill.

Sugarloaf Hill is on the rear side of the Merritt College campus and is in the Leona Canyon Preserve. The East Bay Regional Parks District has plans to enable access to Leona Canyon when the college is closed, though it seems like a low priority for them.

The trail up the hill is not marked or mapped, but it’s not hard to find. As you go up through the woods, you’ll pass exposures of the Leona “rhyolite” that underlies this whole area.

Once above the trees, the campus unfolds below you. This shot also shows the range of habitats on the hill. (It’s a 1000-pixel shot; there are three more later in this post.)

The upper part of the hill is largely grassland with ferns and some bedrock. The soil is very thin. This land used to be grazed. The grassland, says the EBPRD, is dominantly non-native species. It doesn’t mention the ferns, considering them part of the forest biome.

Besides grassland, the hill comprises shrubland and oak/bay woodland. Some parts are pleasingly mixed.

The view west over Leona Canyon juxtaposes grassland and forest. The forest is typical coast live oak and bay laurel, along with buckeye and hazelnut and a whole bunch of different native shrubs. The houses are on Campus Drive.

And this view south over Leona Canyon shows the shrubland, consisting of coyote brush, sagebrush and poison oak. It’s quite overgrown. Absent grazing or fires, this tends to turn into oak/bay forest.

The rocks don’t form many outcrops, per se. There are abundant boulders like this one. They’re naturally covered with lichens, so you have to search to see any details of this metamorphosed volcanic sandstone. Please don’t take a hammer to this stone—besides being protected by EBRPD rules, it deserves to look the way it wants. (1000px)

The point of a hill, so to speak, is its top and the views it makes available. When I climbed Sugarloaf Hill it was a cool and hazy day, so the next two photos are just versions of what you might see from there. Here’s looking north toward the ridge of Redwood Peak, over the ballfields and solar array of Merritt College. (1000px)

And here’s looking south over Leona Canyon from the summit. The rectangle of boulders is I think the work of idlers rather than the remnants of an old foundation. On the horizon, from left to right, are the dimly seen Knife, the dark wooded ridge behind Lake Chabot, and tree-topped Fairmont Ridge behind the hills of Knowland Park. (1000px)

Your viewing may vary.

This entry was posted on 24 August 2015 at 8:02 am and is filed under Leona volcanics, Oakland geology views, Oakland peaks. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.