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IOWA ACADEMY OF SCIENCE Vol. XXVII, 1920 
needed. The advocate of forest preservation can advance argu- 
ments to appeal to every class, whether the so-called practical 
man, the idealist, the nature lover, the artist, the technical expert 
or the mere pleasure seeker. To all there is some feature which 
will carry weight. And to none is the movement to establish a 
great system of forest preserves, of parks big and little, of more 
importance than to those whose concern it is to see that the sup- 
plies of pure, healthful, life-giving water do not fail. There- 
fore it is well that we give thought to the careful and timely con- 
sideration of every plan that will tend to the betterment of 
living conditions by bringing Nature closer to Man and making 
her serve him more completely. 
Iowa G^Sological Survey. 
REFERENCE WORKS CONSULTED 
The Conservation of Natural Resources in the United States, Charles R. 
Van Hise. 
Notes on Hydrology, Daniel W. Mead. 
Elements of Hydrology, Adolph F. Meyer. 
Underground Waters, W. C, Mendenhall, U. S. G. S. Water Supply 
Paper 234. 
The Theory of Underdrainage, W. J. Schlick, Bull. 50, Eng. Experiment 
Sta., Iowa State College. 
Some Problems in Conservation, S. W. Beyer, Presidential Address, 
Iowa Academy of Science, Proceedings, Vol. XXVI, 1919. 
