Toggle navigation
Login
Advanced Search
Basic Search
having these words in the Title
written by this Author
written on this Date
containing this Exact Phrase
containing all these Words
and
or
but not
having these words in the Title
written by this Author
written on this Date
containing this Exact Phrase
containing all these Words
and
or
but not
having these words in the Title
written by this Author
written on this Date
containing this Exact Phrase
containing all these Words
Narrow to this collection(s):
Language
Literature
Philosophy and Religion
Political Science and Law
Science and Mathematics
Social Science
U.S. History
World History
Authors
Topics
Events
Contents
Browse the Entire Original Sources Database
Science and Mathematics
>
Life Science
>
Ecology
World History
U.S. History
Social Science
Science & Mathematics
Political Science & Law
Philosophy & Religion
Literature
Language
From "the Rivers and Valleys of Pennsyvlvania," National Geographic Magazine, Vol. 1, Pp. 15– 71, 1889