ACKNOWLEDGMENTS 



ARE DUE TO 



JOSEPH JEAITES, AND WILLIAM P. WILSTACH, 



Through whose just appreciation of scientific research and liberaHty, a preliminary geological explo- 

 ration was made, and the Academy of Natural Sciences was provided with the means by 

 which it has been enabled to publish the present volume. 



ACKNOWLEDGMENTS 



ARE LIKEWISE DUE TO THE 



Smithsonian Institution, at Washington, the Academy of Sciences of St. Louis, and to Prof. 



James Hall, of Albany, for the unrestricted use and loan of the greater portion of the 



material of that part of the work on " The Extinct Mammalian Fauna 



of Dakota and Nebraska." 



