THE PKAIEIES 235 



— Todd, James E. — Xotes on the Distribution of Timber in South- 

 western Iowa, with inferences concerning the Origin of Prairies. 

 — American Naturalist, vol. XII, pp. 91-96. Variable humidity 

 of air and soil. 

 1879 — Swallow, G. C. — Prairie and Timber. — In Switzler's History of 

 Missouri, pp. 528-529. Prairie when surface emerged from 

 water. Fire checked forest. 

 1880 — Winchell, N. H. — Eighth Annual Eeport of the Geological and 

 Natural History Survey of Minnesota. Fires, p. 96. List of 

 prairie plants, p. 97. 



— Todd, J. E. — Notes on the Distribution of Timber in Southwestern 

 Iowa, with Inferences concerning the Origin of Prairies. — Brief 

 abstract. Proceedings of the Iowa Academy of Sciences for 1875- 

 1880, p. 14. Variation in humidity of air and soil. Published 

 in full in American Naturalist, 1878. 



— Aughey, Samuel. — The Physical Geography and Geology of Ne- 

 braska. Fires, p. 42. Hard surface due to tramping of "mil- 

 lions of buffalo and other wild animals." 

 1881 — Hilton, H. R. — The Kainfall in its Eelation to Kansas Farming.— 

 Transactions of the Kansas Academy of Science for 1879 and '80^ 

 vol. VII. Buffaloes, prairie fires, hot winds, p. 42. 

 1882 — Anders, J. M. — Forests — Their Influence Upon Climate and Eain- 

 fall. American Naturalist, vol. XVI, pp. 19-30. (Eeview in 

 Popular Science Monthly, vol. 21, p. 562). Discusses relation 

 of forest and moisture. 



— Whitney, J. D. — The Climatic Changes of Later Geological Times. 

 — Memoirs of the Museum of Comparative Zoology, vol. VII, 

 part II. Eainfall, fine soil, etc., pp. 166-183. 



— Worthen, A. H. — Economic Geology of Illinois, vol. Ill, pp. 9-11. 

 Excessive moisture in part. Fine soil. Topography and plants 

 are also discussed in county reports, reprinted from Shaw (1873) 

 and Broadhead (1875). 

 1883 — American Encyclopedia.— Prairie, vol. XIII, p. 802. Finely com- 

 minuted soil. 



— Howell, Thomas J. — The Geological Distribution of North Ameri- 

 can Forests. — Popular Science Monthly, vol. 23, pp. 517-524. 

 "Loess is not capable of sustaining forest-growths for any length 

 of time." Geological. 



— McGee, W. J. — The Geological Distribution of Forests. — Popular 

 Science Monthly, vol. 24, p. 115. Drift plains timberless, loess 

 covered with trees. 

 1886 — Campbell, John T. — Causes of Forest Eotation. — American Natur- 

 alist, vol. XX, pp. 521-527, and 851-856. Fires. 



— Winchell, Alexander — Walks and Talks in the Geological Field. 



1st ed. Prairies of lacustrine origin and kept treeless by fires. 



1890 — Mayr, H. — Die TValdungen von Nordamerika — (Quoted by Schim- 



