The Geology of Chaco Canyon, New Mexico In Relation To The Life And Remains Of The Prehistoric Peoples Of Pueblo Bonito Smithsonian Miscelleanous Collections Volume 122, Number 7

Cover

Foreword

Introduction

Plan of the report

Physiography of Chaco Canyon

General relations
Climatic conditions affecting geologic processes
Excavation of Chaco Canyon
Alluviation of the canyon floor
Date of recent stream trenching

Present geologic processes

Weathering and erosion of the cliffs
Wind work
Alluvial fans
Adobe flats
Erosion in the arroyo

The valley alluvium

Materials of the fill
Arrangement of the materials
Depth of the alluvium
Human relics in the valley fill

Complex character of the valley fill

Relation of human relics to main valley fill

The buried channel and its significance

Buried channels similar to the post-Bonito channel on other streams

Geologic evidence on the means of livelihood of Chaco Canyon peoples

Floodwater farming

Arroyo formation and floodwater farming

Cause of alternate erosion and sedimentation

Detailed sections in the recent alluvium

Sections in the main valley fill
Sections in the buried, or post-Bonito Channel

Summary

Bibliography

PLATES

1. Pueblo Bonito from the north cliff

2. Upper: Fajada Butte, from Pueblo Una Vida
Lower: Small ruin in a northern branch of Chaco Canyon

3. Left: Cleavage planes in north wall of Chaco Canyon
Right: Pueblo III fireplace at section 5

4. Upper: Niches and dunes, north wall of Chaco Canyon, near mouth of Escavada Wash
Lower: "Stonelace" on detached block

5. Upper: Looking down Chaco Canyon from Pueblo del Arroyo
Lower: Recently fallen arroyo bank

6. Upper: Small-house ruin, destroyed by floods
Lower: Pueblo I pit house

7. Upper: Buried channel at section 16
Lower: Buried channel at section 4

8. Upper: Mouth of Rincon del Camino
Lower: Lateral erosion caused by drainage from The Gap

9. Upper: Skeleton 6 feet below surface
Lower: Hearth at depth of 12 feet 8 inches

10. Upper: Horses crossing the Chaco in flood
Lower: Middle south wall of Pueblo del Arroyo

11. Left: Pit house below nearby Pueblo III ruin
Right: Pueblo I pot in sand dune

FIGURES

1. Map of Chaco Canyon showing present and post-Bonito channels

2. Northwest portion of New Mexico

3. Bank of Chaco between sections 5 and 16