760,000 years ago the eruption of the Long Valley Caldera (see below) deposited a series of layers on the graveled earth here, a layer of white pumice, a 200-foot layer of beige volcanic rock, and a 500-foot layer of darker volcanic rock.
(the eruption of the Long Valley Caldera (see below; deposited; a series of layers on the graveled earth here; T:760,000 years ago)
the eruption of the Long Valley Caldera (see below
deposited
a series of layers on the graveled earth here T:760,000 years ago