Overview of the notebooks: Why Gilbert went to the Henry Mountains. Getting there, more than 200 miles from Salt Lake City, 20 days travel, mostly by pack train; use of prehistoric trails for finding water and routes to passes and passable canyons. Problems with names.
While learning the stratigraphy along the route to the mountains, Gilbert discovers two stages of structural deformation, now known as Laramide and middle Tertiary.
Lavas or intrusions? Discovering that the “lavas” actually are intrusions leads to discovering the form of the intrusions and the fact that intrusions deform the host rocks into which they are intruded. Erosion, transportation, and corrasion. A third of Gilbert’s monograph is devoted to land sculpture.
Surveying the topography, the first one-degree topographic quadrangle maps of that area.
References cited and some related ones.