History 101:
Industry of the Beavers (1731)

They fell large trees with their teeth, in such a manner as to make them come cross the rivulet. To lay the foundation of the dam, they make mortar, work up and finish the whole with great order and wonderful dexterity.

Inset from Map: “A new and exact map of the dominions of the King of Great Britain on ye continent of North America” by Herman Moll (1731)

Library of Congress gm71005441

For more see: What did Europeans see when they looked at the New World and the Native Americans?