PROFESSOR R. S. WOODWARD,
President of the American Association for the Advancement of Science.
THE
POPULAR SCIENCE
MONTHLY.
AUGUST, 1900.
RHYTHMS AND GEOLOGIC TIME.[A]
By G. K. GILBERT,
UNITED STATES GEOLOGICAL SURVEY.
[A] Read to the American Association for the Advancement of Science, at New York, June 26, 1900, as the address of the retiring President.