ILLUSTRATIONS 



Page. 

 Plate I. Map of surveyed areas. Folded in pocket 



II. Diagram of control 14 



III. Baldwin base-measuring device 44 



IV. Signal 50 



V. Eight-inch theodolite and tripod 54 



VI. Johnson plane-table — general view 80 



VII. Traverse plane-table 86 



VIII. Types of topography, Great plains 112 



IX. Types of topography, Atlantic plain 113 



X. Types of topography, Cumberland plateau 114 



XI. Types of topography, Canyons in homogeneous rocks 115 



XII. Types of topography. Canyons in rocks not homogeneous 116 



XIII. Types of topography, Grand canyon of Colorado river 117 



XIV. Types of topography, Water gaps, Pennsylvania 118 



XV. Types of topography, Mississippi river ridge 121 



XVI. Types of topography, Drumlins 122 



XVII. Types of topography, Moraines _ 123 



XVIII. Types of topography, Cirques 124 



Figure 1. Astronomical transit and zenith telescope 18 



2. Chronograph 20 



3. Switchboard 34 



4. Signal and instrument support '. 51 



5. Heliotrope, Coast Survey 52 



6. Heliotrope, Steinheil 53 



7. Eight-inch theodolite — detail 55 



8. Johnson plane-table tripod head — section 81 



9. Douglas odometer 87 



10. Small telescopic alidade 89 



11. Aneroid 90 



12. Aneroid 90 



13. Cross sections of canyons 119 



14. Cross sections in inclined beds 120 



XI 



