LIST OF ILLUSTRATIONS xv 



PAGE 



FIG. 50. Lakes Chicago, Saginaw, and Maumee . . . . 81 



FIG. 51. Lake Chicago at a Later Stage and Lake Warren . . 83 



FIG. 52. Lake Algonquin 84 



FIG. 53. Map Showing Successive Shore Lines of Lake Chicago . 85 



FIG. 54. Grooves and Potholes in Bed of Outlet of Lake Chicago . 86 



CHAPTER VI 



FIG. 55. Spring Flowers of the Forest Floor . . . . . 91 



FIG. 56. Fresh- Water Crustaceans 93 



FIG. 57. Map Showing Relation of Rainfall to Evaporation in 



Eastern United States 95 



FIG. 58. Map of Forest, Prairie, and Plains Regions in Eastern 



United States 96 



FIG. 59. Diagram of Rates of Evaporation in Contiguous Regions 



(Adams) 97 



FIG. 60. The Cactus of the Dunes, Opuntia Rafinesquii ... 98 



FIG. 61. The Six-lined Lizard, Cnemidophorus sexlineatus . . 99 



FIG. 62. Relative Evaporation Rates in the Strata of the Forest . 100 



FIG. 63. Wild Lettuce, Lactuca scariola 101 



FIG. 64. Dissected Leaves of Bladderwort, Hornwort, and Milfoil; 



Utricularia, Ceratophyllum, Myriophyllum . . .103 



FIG. 65. Closed Gentian, Gentiana Andrewsii 107 



FIG. 66. CuponStemotSilphiumperfoliatum . . . . 108 



FIG. 67. Digger Wasp, Bembex spinolae no 



CHAPTER VII 



FIG. 68. Newly Formed Sand Bar Offshore in Dunes . . .113 

 FIG. 69. Small Dunes Held by Prostrate Juniper, Juniper us 



horizontalis .114 



FIG. 70. Panne at Miller 115 



FIG. 71. Double Row of Seedlings. Same Two Years Older . . 116 



FIG. 72. Sea Rocket, Cakile edentula 117 



FIG. 73. Bugseed, Corispermum hyssopifolium 117 



FIG. 74. Beach Pea, Lathyrus maritimus 117 



FIG. 75. Cinquefoil, Potentilla Anserina 117 



FIG. 76. Wormwood, A rtemisia caudata 117 



FIG. 77. Rye Grass, Elymus canadensis 117 



FIG. 78. Winged Pigweed, Cycloloma atriplicifolium . . . .117 



FIG. 79. Green Milkweed, A cerates mridiflora 117 



FIG. 80. Seaside Spurge, Euphorbia polygonifolia . . . .117 



FIG. 81. Cocklebur, Xanthium echinalum 118 



