Letter from Arno B. Cammerer to Carl Hayden on building a Union Chapel in the Grand Canyon.

Letter from Arno B. Cammerer to Carl Hayden regarding the storage of dynamite in Shoski Canyon. Written in red pencil at the top, "My dear Jesse, For your(?) further information, Jack."

Letter from Arno B. Cammerer to Carl Hayden on the investigation by Superintendent Crosby regarding the TNT stored in the Grand Canyon.

Letter from Arno B. Cammerer to Carl Hayden informing him of the removal of the dynamite from Grand Canyon Village to a point near Rowe Well.

Geological examination of the park canyonland, with description of the rocks, water sculping process, volcanic cones and outflows, and land erosion. This edition is Volume 2, 1977 reprint, of the author's 1882 monograph. Includes 12 color maps, 10 color views and is number 280/1500.

Letter from Arno B. Cammerer to J. R. Eakin describing the procedure for purchasing Bright Angel Trail.

Proposed admission fees to Grand Canyon National Park.