Geologic map of the Mount Abbot quadrangle, central Sierra Nevada, California

The Mount Abbot quadrangle comprises about 240 square miles of high montane to alpine terrain straddling the Sierra Nevada crest between Fresno and Bishop, California. About three-fourths of the quadrangle lies in the John Muir Wilderness, and the famous John Muir Trail, travelled by thousands of vacationers each summer, crosses the full length of the quadrangle from north to south (Geologic map).

The geologic map of this quadrangle is one of a series across the central Sierra Nevada which have been prepared as background for continuing studies of the geologic history and mineral deposits of this majestic mountain range. This brief explanatory text, however, is written primarily for the non geologist vacationer who wants to familiarize himself with the rocks and geologic features of the quadrangle. Included in this explanation are a geologic guide to part of the John Muir Trail, a glossary of geologic terms used in this report, and annotated references to further reading.