IV 



fcssor Lesqucreux, with equal sincerity and force, decides, from tlic lessons 

 of tlie fossil vegetation, that it belongs to the Tertiary epoch. 



The present volume will be followed in due time by two others by the 

 same author, on the Vertebrata of the Tertiary Lake-Basins of the "West. 

 I have the honor to be, your obedieut servant, 



F. V. HAYDEN, 



United States Geologist. 

 Hon. 1>. R. CowEN, 



Acting Secretary oj the Interior. 



