Archive for January, 2010

Eastern knockers

31 January 2010

Recently I visited some of the knockers in the steep hillside east and south of Mountain View Cemetery. These three are chert of deep-sea origin; the middle photo best shows its typical “ribbon” bedding.

knockers

knockers

knockers

This area borders the steep gorge of Moraga Canyon and harbors a number of deer and turkeys, among other wildlife.

Chabot gorge

24 January 2010

As you walk up to Chabot Dam the valley carved by San Leandro Creek opens up below, and it’s quite impressive (click photo for bigger version):

chabot gorge

At the top, the dam is buttressed against a ridge of the volcanic rock of Leona Quarry. Before the dam was built, there must have been quite a defile here:

chabot dam

The rock is nicely exposed just next to the dam, worth taking a close look at:

chabot rock

The gorge is more than 100 meters deep and only a couple hundred meters wide. Like other Oakland stream valleys, it seems large for the stream running through it today. I think much of the hardest work carving the canyons was done during periods of much wetter climate than today. Or maybe it was drier, with the land being more prone to desert-style flash floods.


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