Route by way of San Xavier and Twin Buttes--. Routes in and to the Altar Valley--- Florence to Casa Grande Ruins___. Casa Grande to Pozo de Luis, Sonora__ ILLUSTRATIONS PLATE I. Map of the arid region of the United States showing areas covered by guides to watering places and other maps and watersupply papers of the United States Geological Survey... Page XVI II. Relief map of the western part of the Papago country, Ariz. In pocket. or "béchete" hole at Tule Tank_--_. 40 40 VI. A, Luxuriant vegetation near Big Fields; B, Desert willow in VII. A, Palo verde with mistletoe on west side of Growler Moun- VIII. A, Forest of dead mesquite north of Crater Mountains; B, Tilted IX. Reconnaissance geologic map of the Papago country... 40 40 In pocket. 84 XI. A, Growler Mountains, from Bates Well; B, Growler Moun- 84 XII. A, Raven Butte, from the east; B, Lava-capped mountain in the 84 XIII. A, Granite slope exposed by removal of talus by ephemeral stream at Raven Butte; B, Mountain slope and dissected pediment at Sand Tanks.. 84 XIV. A, Pass west of Tule Tank; B, Niches in granite at Tinajas 84 XV. A, Headwater basin and dissected pediment in the Tumacacori XVI. A, Charco near Pozo Redondo; B, Miniature canyons near head of a charco, La Quituni Valley.... XVII. A, Black Tanks; B, Tule Tank about a week after a rain... a week after a rain__._. 84 126 126 126 XIX. A, Stand for selling water on main street of Clarkstown; B, House in Old Ajo-_-_ 126 XX. A, Represo at Copeka; B, Water catch at Fortuna mine.... 146 nemo 146 XXII. A, Represo at Comovo; B, Compartidero, a represo used for watering cattle. _ _ . 146 XXIII. A, Mesquite tree of sprawling habit south of Casa Grande ruins; 146 north___ 164 XXV. A, Cochibo; B, Papago Well.. 164 XXVI. A, Artesa Pond; B, Papago farming near Toapit.......... 264 XXVII. Road across a sandy wash dug out and corduroyed with brush.. FIGURE 1. Map of the Papago country, Ariz., showing principal roads 2. Geologic cross section in the western part of the Sand Tank 3. Geologic cross section in the Tule Mountains. 4. Geologic cross section of the southern part of the Lechuguilla 72 5. Diagram to show the range in grade of mountain slopes---- 81 as observed of gullied and ungullied mountains of approxi- 7. Diagram showing four stages in the erosion of a block of the 8. Cross section of niche in granite at Tinajas Altas_ 9. Diagram illustrating weathering of Tertiary arkose conglom- 10. Cross section of a niche in coarse conglomerate, Papago 11. Map of part of the Sacaton Mountains___ 83 88 91 12. Map of the northern border of the Baboquivari Mountains___ 98 14. Diagram showing the structural relations assumed for a 100 15. Cross sections on the north and west sides of the Babo- 101 16. Cross section of part of Santa Cruz Valley (Nogales Wash), 111 111 18. Cross section of Santa Cruz Valley at Jaynes___ 112 112 20. Cross section through the northern pond at Susuta, Sonora__ 121 125 126 23. Sketch map of Baker Tanks_-. 128 24. Section along stream channel at Tabaseca Tank, Riverside 129 25. Diagram showing the production of falls and tanks by erosion of mountain pediment on a new grade_ 130 26. Sketch map of the Black Tanks, Crater Mountains___. 30. Idealized diagram to show effect of joint system on course of stream and position of tanks at Tinajas Altas_ 134 31. Diagram showing water catch at Old Ajo----- 137 32. Sketch map showing drainage area at water catch near For- 138 FIGURE 33. Reinforced-concrete cistern for water catch_ Page 140 34. Diagrammatic map showing location of represo at one side 145 35. Idealized map showing use of run-off from road ruts and 147 36. Profile through typical Papago represo.... 148 148 38. Diagram showing the use of logs and brush for diversion 149 39. Diagram showing construction of a water drop to prevent 150 40. Diagram showing rock-fill dam for an artificial spring______ 152 162 PREFACE By O. E. MEINZER The arid region of the United States, as outlined on Plate I, covers about 500,000 square miles, or one-sixth of the entire country. This vast region includes some large irrigation districts and well-watered mountains, but most of it is so arid that it can not safely be traversed by anyone who does not have adequate information regarding the location of watering places. The desert is not vanishing, although here and there relatively small tracts of it have been reclaimed by irrigation, and the aggregate number of watering places has been slowly increasing. It has, however, become much more accessible than formerly-first through the building of railroads and recently through the use of automobiles. In 1917 the sum of $10,000 was appropriated by Congress for a survey of desert watering places which had been authorized in an act approved August 21, 1916, as follows: Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That the Secretary of Interior be, and he is hereby, authorized and empowered, in his discretion, in so far as the authorization made herein will permit, to discover, develop, protect, and render more accessible for the benefit of the general public springs, streams, and water holes on arid public lands of the United States; and in connection therewith to erect and maintain suitable and durable monuments and signboards at proper places and intervals along and near the accustomed lines of travel and over the general area of said desert lands, containing information and directions as to the location and nature of said springs, streams, and water holes, to the end that the same may be more readily traced and found by persons in search or need thereof; also to provide convenient and ready means, apparatus, and appliances by which water may be brought to the earth's surface at said water holes for the use of such persons; also to prepare and distribute suitable maps, reports, and general information relating to said springs, streams, and water holes and their specific location with reference to lines of travel. The work thus authorized was assigned to the United States Geological Survey. To the small appropriation made for this purpose was added a part of the Geological Survey's regular allotment for ground-water investigations in the United States, and the scope of the survey was enlarged so as to include a reconnaissance of the ground-water conditions in the area covered. XV |