Transcriber's Note Italicized text is displayed as _Text_ and bold text as =Text=. Whole and fractional parts of numbers are displayed as 4-5/8. Some UTF-8 characters were converted to plain ASCII. To view them, see the HTML or UTF-8 version. DEPARTMENT OF THE INTERIOR. John Barton Payne, Secretary United States Geological Survey George Otis Smith, Director THE PREPARATION OF ILLUSTRATIONS FOR REPORTS OF THE United STATES GEOLOGICAL SURVEY WITH BRIEF DESCRIPTIONS OF PROCESSES OF REPRODUCTION BY JOHN L. RIDGWAY WASHINGTON GOVERNMENT PRINTING OFFICE 1920 +==================================+ | | | THE PREPARATION OF ILLUSTRATIONS | | | | FOR REPORTS OF THE | | | | UNITED STATES GEOLOGICAL SURVEY | | | | | | BY | | | | | | JOHN L. RIDGWAY | | | +==================================+ CONTENTS. Part I. Preparation by Authors. Page. Introduction 7 Purpose and value of illustrations 8 Selection and approval of illustrations 8 Submittal of illustrations 10 Kinds of illustrations 10 Sizes of illustrations 11 Subdivisions of plates and figures 12 Preparation of copy by authors 12 Character of original material 12 Preliminary preparation of maps 13 Material available for base maps 14 Basic features of maps 17 Standard scales 18 Orientation of maps 18 Projection 18 Explanation 19 Titles of maps and other illustrations 19 Symbols used on maps 20 General features 20 Letter symbols 20 Oil and gas symbols 21 Symbols for use on maps showing features of ground water 21 Black-line conventions 23 Materials used in preparing maps 23 Paper 23 Bristol board 24