7

• Page.
• INTRODUCTION . . . 23
  • Area treated . . . 23
  • Sources of data . . . 23
  • Importance of paleontology . . . 24
• PART I. GEOGRAPHY OF THE TEXAS REGION . . . 25
  • The State of Texas . . . 25
    • Area, relations, and subdivisions . . . 25
      • Definition of the provinces . . . 27
  • The relief . . . 29
    • Relation of formation to relief . . . 30
      • Kinds of relief-making rocks in Texas region . . . 31
        • Influence of the marine sedimentaries . . . 32
        • Influence of nonmarine sedimentaries . . . 35
        • Influence of the igneous rocks . . . 36
    • The mountains . . . 37
      • Ouachita system . . . 37
      • Mountains of Trans-Pecos Province . . . 38
    • The plains . . . 39
      • Classification of plains by origin . . . 39
        • Constructional plains . . . 40
        • Destructional plains . . . 41
      • Plains of the Regional Coastward Slope . . . 42
        • The Great Plains . . . 43
        • The prairie plains . . . 44
          • Plains of the East-Central Province . . . 45
          • Plains of the Central Province . . . 46
        • The Coastal Plain . . . 48
      • Plains of the Trans-Pecos Province . . . 50
  • The drainage . . . 51
    • Types of streams . . . 51
    • Direction of flow . . . 52
    • Classification of the drainage system . . . 53
    • Résumé of the drainage system . . . 56
• PART II. GEOGRAPHY OF THE BLACK AND GRAND PRAIRIES AND CROSS TIMBERS (EAST-CENTRAL PROVINCE) . . . 59
  • Relations and soils . . . 59
  • Belts of country . . . 62
  • The relief . . . 63
  • The drainage . . . 64
  • The Black Prairie Subprovince . . . 65
    • Relations, soils, and drainage . . . 65
    • Subdivisions of the Black Prairie . . . 66
      • Inliers of the Black Prairie within the Atlantic Timber Belt . . . 67
      • Eastern marginal prairies . . . 67
      • Taylor Prairie . . . 67