I always look at landscaping rocks. This terrace on a slope facing Elwood Avenue, in the process of being faced with dry-stone masonry, is worth applauding. It has an old-fashioned look, like the WPA-era stone walls up and down the East Bay.
It’s always a gamble hardscaping a cut slope like this. You see plenty of thick concrete walls losing their fight against gravity as the soil creeps downward and outward. This project has two things in its favor. First, the soil is firm clay that has been there, without slumping, for a hundred years since Elwood was paved (the sidewalks date from 1912). Second, if the soil were to start creeping, say because of overwatering or tree growth, the stones can be easily lifted and replaced after fixing the problem.
Naturally, these aren’t local rocks. They’re “natural landscaping rocks” rather than “river rocks,” with a rough surface and signs of long exposure, like lichens. I don’t know where such stone is gathered—probably from talus slopes in the western states. You buy them in wire-wrapped bundles, or gabions. When I drove up through the rangeland of northeast California and central Oregon last month, I saw that gabions are now the material of choice for important fenceposts. No digging needed, and they’re immune to fire. I’m sure the cattle like them for rubbing themselves, too.
Oakland Geology 
7 August 2010 at 11:34 am
you see gabions out here in the midwest where the farmer’s fields grow rocks, the collected them and make gabions in the corners of thier fields to secure thier fences. More space efficient that just piling them at a natural angel of repose.