THE PKAIEIES 237 



— Powell, J. W.— The Physiography of the United States. Eainfall, 

 pp. 70, 71. 



— Tarr, Balph S. — Elementary Physical Geography. — Neither com- 

 pactness of soil nor fires proven sufficient, p. 257. Not dryness, 

 p. 351. 

 1897 — Cameron, John E. — Forest Trees of Delaware County (Iowa) — Iowa 

 Geological Survey, vol. VIII. Timber on rougher areas, p. 193. 

 1897-8 — Shimek, B. — The Flora of the Sioux Quartzite in Iowa. Pro- 

 ceedings of the Iowa Academy of Science, part I, vol. IV, 1897, 

 pp. 72-81 J part II, vol. V, 1898, pp. 28, 31. Lists of prairie 

 plants. 

 1898 — Geikie, James — Earth Sculpture, p. 337. Aqueous sedimentation, 

 or wind action, or both. 



— Marsh, George P. — The Earth as Modified by Human Action. Not 

 fineness of soil, p. 339. Climatic conditions, especially want of 

 spring and summer rains. Eastward, fires. Pasturage of the 

 buffalo. In Wisconsin and Ohio cleared by primitive people and 

 forest renewal prevented by fires and grazing. This is a revised 

 edition of Man and Nature, published in 1863 and 1874. 



— Hitchcock, A. S. — Ecological Plant Geography of Kansas. — 

 Transactions of the St. Louis Academy of Science, vol. VIII, pp. 

 55-69. — Rainfall, p. 56. — Plant lists. 

 1899 — Macbride, Thomas H. — Forestry Notes for Humboldt County 

 (Iowa). — Iowa Geological Survey, vol. IX, pp. 148-149. — Fires 

 rather than soil. Influenced by moisture. 



— Gow, James E. — Forest trees of Adair County (Iowa). — Proceed- 

 ings of Iowa Academy of Sciences vol. VI, pp. 56-63. — Fires, 

 p. 61. 

 1900 — Macbride, Thomas H. — Forestry Notes for Dickinson and Osceola 

 Counties (Iowa), — Iowa Geological Survey, vol. X, pp. 228-239. 

 Fires, etc., p. 230. 



— Macbride, Thomas H. — Forestry Notes for Dubuque County (Iowa). 

 — Iowa Geological Survey, vol. X. Fires, p. 624. 



— Davis, William M. — In Mill's International Geography, p. 739. 

 Prairie fires, fineness of soil, lack of rainfall. Not due to com- 

 mon cause. 



— Pound, Roscoe and Clements, Frederic E. — The Phytogeography 

 of Nebraska. The Prairie-grass formation, pp. 348-350. Char- 

 acteristic plants. 



— Shimek, B. — The Distribution of Forest Trees. — Proceedings of 

 the Iowa Academy of Sciences, vol. A^II, pp. 47-59. Chief cause 

 exposure to wind. Accessory causes, fire, excess of moisture, 

 lack of moisture, temperature, geological formations and soils. 



— Shimek, B. — The Flora of Lyon County (Iowa). — Iowa Geological 

 Survey, vol. X, pp. 157-184. Exposure, pp. 160 and 163. Lists 

 of prairie plants. 



