Archive for April, 2014

Manzanita ridge

28 April 2014

The ridge traversed by Manzanita Drive is one of Oakland’s highest residential areas, higher than 1400 feet. It’s the home-studded rise in the Oakland skyline to the right of Round Top in the blog’s banner image. Here’s the topographic view, from Google Maps:

manz-ridge-topo

. . . and here’s the matching part of the geologic map:

manz-ridge-geo

The ridge crest is held up by the Claremont Chert (Tcc), while Skyline Boulevard and Arrowhead Drive, running parallel just to its south, go through the crumbly Sobrante Formation (Tsm). (The other formations are the Orinda Formation, Tor, and the unnamed Eocene sandstone of upper Shepard Canyon, Tes.) Here’s the chert exposed at the west end of Manzanita; it and the next two photos click bigger.

Click for 800-pixel version

The views are terrific. Here’s the view north over the Huckleberry saddle to the smaller ridge of Claremont Chert that Elverton Drive skirts.

Click for 1000-pixel version

The middle of Manzanita offers fine views of Round Top.

Click for 800-pixel version

And the other end of Manzanita, past the unexpected Hills Swim & Tennis Club, is another saddle at the top of Shephard Canyon where the road to Canyon and Moraga crosses the hills.

skyline-shep-pinehurst-saddle

More than anywhere else in Oakland, this is an island in the sky.

Arroyo Viejo emerges

13 April 2014

Quietly, at the edge of the Coliseum station parking lot, Arroyo Viejo comes out of hiding from beneath Hegenberger Expressway. It runs under the walkway to the Coliseum and joins Lion Creek just short of the bay.

arroyoviejomouth

Even in its coffinlike culvert, the stream wants to curve, laying a gravelly point bar on its left bank and trying in vain to erode the angle of the culvert’s course into a nice meander. Sorry, old creek.


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