Highest point on Knob is pumice-bearing breccia. Below that is outcrop of lava Breccia at top of SW knob. Pumice rich
Volcanism on Unimak Island, Alaska, USA: a special focus on Shishaldin and Fisher volcanoes
This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137
Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.