TABLE OF CONTENTS. 



Letter to the Governor Page 1 



INTRODUCTION. By C. A. White. 



1. Historical Page 7 



2. Popular explanation 12 



3. Classification of Iowa rocks 25 



PAET FIKST. 



PHYSICAL GEOGRAPHY AND SURFACE GEOLOGY. 



CHAPTER I.— SURFACE FEATURES. By C. A. White. 



1 Boundaries and Area Page 28 



2. General Topography 29 



3. Drainage Systems 35 



4. Rivers and their valleys 38 



5. Rivers of the Western S3^stem 44 



6. Rivers of the Eastern System 57 



7. Relative ages of the River Valleys 69 



8. Lakes 70 



9. "Walled Lakes" 74 



10. Sinkholes and Springs 78 



11. Caverns 80 



CHAPTER II.— SURFACE DEPOSITS. By C. A. White. 



1. Drift 82 



2. Altered Drift 101 



3. Alluvium 102 



4. BluffDeposit 103 



5. Other Lacustral and Marsh Deposits 117 



CHAPTER III.— SOILS, Etc. By C. A. White. 



1. Drift Soils 123 



2. Blaff Soil 127 



