22. A. Model of the vicinity of Chicago, showing the position of the outlet of the former Lake Chicago 400 B. Map of Yosemite Falls and its earlier site near Eagle Peak 400 23. A. View of the American Fall at Niagara, showing the accumulation of blocks beneath 414 B. Crystal Lake, a landslide lake in Colorado 414 24. A. Apparatus for exercise in the preparation of topographic maps 468 B. The same apparatus in use for testing the contours of a map 468 C. Modeling apparatus in use 468 ILLUSTRATIONS IN THE TEXT FIG. PAGE 1. Diagram to show the measure of the earth’s surface irregularities 11 2. Map to show the reciprocal relation of areas of land and sea 11 3. The tetrahedral form toward which the earth is tending 12 4. A truncated tetrahedron to show the reciprocal relation of projection and depression upon the surface 13 5. Approximations to earlier and present figures of the earth 15 6. Diagrams for comparison of coasts upon an upright and upon an inverted tetrahedron 17 7. The continents, including submerged portions 18 8. Diagram to indicate the altitude of different parts of the lithosphere surface 18 9. Diagram to show how the terrestrial rocks grade into the meteorites 22 10. Comparison of a crystalline with an amorphous substance 24 11. “Light figure” seen upon etched surface of calcite 25 12. Battered sand grains which have developed crystal faces 26 13. Unassimilated grains of quartz within a garnet crystal 28 14. New minerals developed about the core of an augite crystal 28 15. A common rim of new mineral developed by reaction where earlier minerals come into contact 28 16. Laminated structure of a sedimentary rock 30 17. Characteristic textures of igneous rocks 33 18. Diagram to show the order of sediments laid down during a transgression of the sea 37 19. Fractures produced by compression of a block of molder’s wax 41 20. Apparatus to illustrate the folding of strata 41 21. Diagrams of fold types 42 22. Diagrams to illustrate crustal shortening 42 23. Anticlinal and synclinal folds 43