x ILLUSTRATIONS 



41. Map Showing Extent and Southern Limit of Glaciation in North 



America 46 



42. Map Showing the Three Centers of Ice Accumulation in North 



America 47 



43. Map Showing Extent of Ice-sheet, Europe 48 



44. A Section Showing the Black Sangamon Soil with the Illinois Glacial 



Drift Beneath and the lowan Loess Above, with the Present Soil 

 on the Surface 49 



45. A Section Showing Bloomington Gravel, Shelbyville Till Sheet, lowan 



Loess, Sangamon Soil, Silt Below Peat 49 



46. Granite Boulder Weighing About 30 Tons, at Depot of Northwestern 



R. R., Waukegan, Illinois 51 



47. Heap of Boulders Collected from a Moraine in Northern Illinois .... 51 



48. A Dust Storm in Kansas, May 26, 1912 54 



49. Sand Dune Advancing Over Forest, Beaufort Harbor, N. C 55 



50. A Resurrected Forest, Dune Park, Indiana 55 



51. Wind Ripples on Sand Dune 56 



52. Transplanting Beach or Marram Grass 56 



53. The Grass in the Foreground Holds the Sand Which Drifts from the 



"Waste" Beyond the Fence 57 



54. Sand is Being Held by Vegetation 57 



55. Fences Being Used to Check the Movement of Sand 58 



56. Large "Blowout" in Sand Area, Mason County, Illinois 59 



57. Black Locusts Growing on Sand to the Right, Drifting Sand on Left. 59 



58. The Trailing Wild Bean Makes a Large Growth 60 



59. Pines Growing on Sand Dunes in England 60 



60. Alluyiation by Glacial Stream, Below Hidden Glacier, Alaska 62 



61. Calcium Carbonate Concretions from the Loess of Illinois 63 



62. A Road Through a Deposit of Deep Loess Along the Lower Illinois 



River 63 



63. Map of United States, Showing Timber and Prairie Areas 76 



64. Soil Samplers 119 



65. Bottle for Subsidence Method of Mechanical Analysis 125 



66. Nobel's Elutriator . . 126 



67. Schone's Elutriator 126 



68. Hilgard's Churn Elutriator 126 



69. Machine for Centrifugal Analysis of Soils 127 



70. Yoder's Centrifugal Elutriator 127 



71. King's Aspirator for the Determination of the Effective Diameter of 



Soil Particles 128 



72. Shrinkage of Different Types of Soil 133 



73. Cra,cks in Black Clay Loam After a Long Dry Period 136 



74. Fragments of Plants Found in Soils 143 



75. Fragments of Insects Found in Soils 143 



76. Specimens of Charcoal and Charcoal-like Material Found in Soils 146 



77. Specimens of Coal Found in Soils 146 



78. The Effect of the Removal of Humus and of Wetting and Drying 



Upon Granulation 149 



79. Arrangement of Apparatus for Determining Organic Matter by 



Chromic Acid Method 155 



80. Clover on Gray Silt Loam on Tight Clay 159 



81. How Does This Man Handle Manure? 165 



82. When the Spreader is Filled the Manure is Hauled to the Field 165 



83. Manure Spreader in Action 167 



84. An Expensive and Wasteful Way of Handling Manure on the Farm . 169 



85. Burning Corn Stalks 170 



86. Adding Organic Matter to the Soil in the Form of Sweet Clover 172 



