IV 



fessor Lesquereux, with equal sincerity and force, decides, from the lessons 

 of the 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 obedient servant, 



F. V. HAYDEN, 



United States Geologist. 

 Hon. B. R. Cowen, 



Acting Secretary of the Interior. 



