Nature Notes From Crater Lake
Volume 3, No. 2, August 1930
A Glaciated Surface
By F. Lyle Wynd
The greatest geological characteristics
of the Crater Lake Area are those of tremendous volcanic activity and
extended glaciation.
Characteristic glacial valleys and an
intricate system of moraines may be found throughout the region, but
only very rarely have glacial striae and polish been seen. This is due
to the fact that during the last eruption of the Mount Mazama a deep
blanket of pumice and finely powdered material was explosively thrown
out, covering what striae and rock-polish that may have been present.
