Steve Lipshie describes for the group the Bishop Tuff in Owen's Gorge. The tuff unit that the road is cut into and that is behind Steve's back is the same as the lower ash flow (ignimbrite) that we saw in the quarry on day 2, but immensely thicker here nearer the source. The thin white unit deposited in the swale over Steve's head is the same as airfall ash number 2 that we saw in the quarry, but much thinner here, perhaps due to erosion by the overriding upper ash flow. The ash flow above the swale corresponds to the upper ash flow in the quarry.
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