Perhaps the ultimate in Yosemite mapping, from the geomorphologist’s point of view, is the Yosemite Valley Sheet, prepared by the United States Geological Survey in coöperation with the State of California. The map is of large scale, and the topography, the work of François E. Matthes, is extremely accurate, giving it something of the quality of a relief map on a plane surface. Even the overhangs of the cliffs are depicted. The 1946 edition of this sheet falls short in that detail has been lost through the overprinting of topographical shading. Considered for their practical guidance to the user of Yosemite trails, the U. S. Geological Survey maps of the back country are most important. The 700-odd miles of maintained trails which make much of the park accessible to the hiker and rider appear upon these topographical maps in true relationship to the physical features through which they pass. A useful guidebook covering the routes in and around Yosemite Valley, as well as many of the park trails south of the Tuolumne River, is the _Illustrated Guide to Yosemite Valley_, by Virginia and Ansel Adams. In this volume road and trail diagrams are stylized to impart, simply and directly, information on distances, altitudes, and relative positions. Walter A. Starr, Jr.’s _Guide to the John Muir Trail and the High Sierra Region_ includes a section (Part I) on the trails of the Yosemite National Park region, and the map which accompanies it relates the high country trails to the road systems of both the east and west slopes. This guide, published by the Sierra Club, is kept up-to-date through the production of frequent editions. Early Indian Routes Before the story of trail building within the national park is presented, it is worthwhile to review briefly the history of the approach routes outside the present limits of the park—the trails followed by the Indian fighters and miners. Most of the early routes of the white man across the Yosemite Sierra and out of the valley itself followed Indian trails. The discovery of arrow points and knife blades on the slopes of some of the higher Yosemite peaks indicates that the Miwok Indians entered the high, rough country in pursuit of game. Their regularly established trade with the Monos also is a matter of record. Indian Canyon and the Vernal and Nevada falls gorge of the Merced provided two much used routes out of the valley to the east, and the Old Inspiration Point-Wawona-Fresno Flats-Coarse Gold route gave access to the foothill country to the west. There were other ancient routes on the valley walls accessible to an able-bodied Indian; however, except in emergency they probably found little use.