DEVONIAN FISHES OF IOWA 291 



Acknowledgments. 



The writer finds it difficult to express adequately the sense of 

 his indebtedness to Professor Calvin, Director of the Survey, 

 for the generous and active assistance he has rendered in the 

 prosecution of the present Report, as well as for helpful advice 

 and constant encouragement. To him alone is due whatever 

 credit belongs to the inception of a work of this kind, and its 

 publication in the present form, which marks a radical departure 

 from the general plan and purpose of previous Survey Reports. 

 Having first brought to light one of the most remarkable fish- 

 faunas yet discovered in any region, namely that which charac- 

 terizes the. State Quarry beds of Johnson county, it is due to his 

 appreciation of the scientific importance of the great quantity 

 of unworked material obtained from this and other Devonian lo- 

 calities, both within the political boundaries of the State, and 

 extra-limital, that an exception in favor of a volume of this 

 character should be made in a series of principally economic 

 reports. 



In addition, sincere and cordial thanks are extended to Pro- 

 fessor Calvin and his assistants on the Survey, notably Profes- 

 sors J. A. Udden and W. H. Norton, for the loan or other use of 

 numerous valuable specimens. For similar courtesies the writer 

 is indebted to the authorities of several large museums, the 

 American, New York State, Yale and Harvard. For many and 

 very special favors thanks are gratefully rendered to his friends 

 and colleagues, Professors Bashford Dean, John M. Clarke, 

 Charles Schuchert, Arthur M. Miller, and Dr. Stuart Weller. 



To his foreign associates, Drs. Ramsay H. Traquair, A. Smith 

 Woodward, Otto Jaekel, Louis Dollo, and others, the writer is 

 indebted for a number of helpful suggestions received through 

 correspondence, and above all for the wealth of information con- 

 tained in the large body of publications emanating from these 

 accomplished masters of a difficult field of research. The extent 

 to which their published writings have been drawn upon in the 

 preparation of the present Report will be evident to all ; and 

 the writer's sense of obligation for this aid is correspondingly 

 great. 



