Rocks & Minerals

Ancient Landscapes of the Grand Canyon Region

Texas Gemstones

The Book of the Pearl

The Geology of Mt. Mansfield State Forest

Earth Features and Their Meaning An Introduction to Geology for the Student and the General Reader

Notes on Collecting and Preserving Natural-History Objects

The Geology of Groton State Forest

Cave Regions of the Ozarks and Black Hills

Across Mongolian Plains

Underground Treasures: How and Where to Find Them

The Ornithosauria

A Short History of the Academy of Natural Sciences of Philadelphia

Devils Tower National Monument

The Glaciers of the Alps

Underground Treasures: How and Where to Find Them

Pleistocene Bats from San Josecito Cave, Nuevo Leon, Mexico

Fragments of Earth Lore: Sketches & Addresses Geological and Geographical

Biology, The Myth Of Evolution