3

• Page
• Abstract 1
• Introduction 2
  • Location 2
  • Previous work 2
  • Field work 3
  • Acknowledgments 3
• Geography 3
  • Physical features of trans-Pecos Texas 3
    • Basin and Range province 4
    • Mexican Highlands province 4
    • Great Plains province 5
  • Climate 5
  • Vegetation 5
  • Erosional agencies 6
  • Marathon region 7
    • General features 7
    • Escarpments bordering the Marathon Basin 8
      • Escarpments and plateaus on the east and south sides 8
      • Escarpments on the north side 10
      • Escarpments on the west side 11
      • Relation of escarpments bordering the Marathon Basin to the later tectonic movements 12
    • Ridges of the Marathon Basin 13
      • Novaculite ridges 13
      • Dimple limestone ridges 13
      • Even summit levels on the ridges 14
    • Lowlands of the Marathon Basin 14
      • Rock floors, their nature and origin 14
      • Comparison of rock floors previously described with those in the Marathon Basin 15
      • Rock floors of the Marathon Basin 16
      • Erosion and deposition on the rock floors 16
      • Streams of the Marathon Basin 19
• Stratigraphy 19
  • General outline 19
  • Pre-Cambrian rocks 21
    • Pre-Cambrian rocks north and south of Marathon 21
    • Fragments of crystalline rocks in the Paleozoic sediments at Marathon 21
    • Depth of the pre-Cambrian floor in the Marathon Basin 22
  • Cambrian system 22
    • Dagger Flat sandstone 22
      • General features 22
      • Local features 22
        • Dagger Flat area 22
        • Threemile Hill 23
        • Woods Hollow Tank 23
        • Marathon anticlinorium 23
      • Microscopic character 23
      • Fossils and age 23
      • Stratigraphic relations 24
    • Problem of the Brewster formation 24
  • Ordovician system 25
    • Historical summary 25
    • General features 25
    • Marathon limestone 26
      • General features 26
      • Local features 26
        • Marathon anticlinorium 26
        • Dagger Flat anticlinorium 29
      • Fossils and age 30
      • Stratigraphic relations 30