[1]The X pumice occurs as scattered fragments and does not form a
continuous layer.
[2]Ages of more than 150 and less than 6,000 years cited in this report
are based on radiocarbon determinations which have been corrected by
the use of a C₁₄ half life of 5,730 years and for variations in
atmospheric C₁₄ (H. E. Suess, written communication to Meyer Rubin,
1968).
[3]For more information about glaciers read “Glaciers” by Robert P.
Sharp, published in 1960 by the University of Oregon at Eugene.
[Illustration: DEPARTMENT OF THE INTERIOR · MARCH 3, 1849]