TABLE OF CONTENTS. 



PAGE 



Letter of Transmittal 8 



Table of Contents 6 



Officers of the Academy 7 



Constitution of the Academy 9 



Membership of the Academy 13 



Proceedings of the Seventeenth Annual Session 17 



Neci'ology — W. M. Beardshear 22 



Presidential Address, by H. E. Summers 26 



Living Plants as Geological Factors, by B. Shimek . 41' 



Some Observations Upon the Action of Coherers Wlien Subjected to Direct Electro- 

 motive Force, by F. F. Almy 49 



Tlie Accretion of Flood Plains by Means of Sand Bars, by Howard E. Simt^son. .. 54 



Ecological Notes on the Vegetation of the Uintah Mountains, by L. H. Pammel 57 



The Membrane Bones in the Skull of a Young Amphiuma, by H. W. Norris 69 



The Solar Surface During the Past Twelve Years, by David E. Hadden 74 



The Duck Hawk (Falcn Peregriniis Anatum) in Iowa, by B. H. Bailey 93 



Significance of the Occurrence of Minute Quantities of Metalliferous Minerals in 



Rocks, by Charles R. Keyes 99 



Genesis of Certain Cherts, by Charles R. Keyes . 108 



Comparative Values of Different Methods of Geologic Correlation in the Mississippi 



Ba4n, by Charles R. Keyes 105 



The Chemical Composition of Nuts used as F. od, by J. B. Wtums and Alice W. 



Hess 108 



The Preparation of Ammonia Free Water for Water Analysis by J. B. Wecms, C. E. 



Gray and E. C. Myers 112 



The Preparation of Phenyl Ether, by A. N. Cook 113 



The Sioux City Water Supply, by A. N. Cook and W. -T. Morgan 122 



The Toledo Lobe of lowan Drift, by T. E. Savage 123 



The Origin of the Lignites of North Dakota, by Frank A. Wilder 129 



The ScrophulariaceiB of Iowa, by T. J . and M. F L. Fitzpatrick 136 



