Hans Cloos Quote

By far the most important books for geology students were the quarries and clay pits, the cliffs and creek beds, the road and railroad cuts in woods and fields. Our words and letters were the imprints of plants and animals in stone, the minerals and crystals, and our vast inexhaustible, incorruptible, and infallible library was nature itself.

Conversation with the Earth, Chapter II (p. 28)