G. K. Gilbert’s report on the Henry Mountains is classic for its contribution to knowledge of igneous structures, especially laccoliths, for its contributions to the understanding of geomorphic processes, and as an example of excellent technique in geologic reporting and writing. Present-day Ph.D. candidates and many of their faculty would do well to adopt Gilbert’s technique.

His accomplishments are especially impressive when viewed in the perspective of the status of geologic knowledge at the time he did his work and the hazards accompanying his field work. His conclusions, seemingly elementary today, were received with skepticism by many of his contemporaries...