TO 

 ELISHA GRAY 



CHEVALIER DE LA LEGION D'HONNEUR 



INVENTOR OF THE HARMONIC TELEGRAPH, THE TELEPHONE 



AND THE TELAUTOGRAPH 



WHOSE INTELLIGENT INTEREST IN GLACIAL GEOLOGY 



AND WHOSE GENEROUS APPRECIATION OF MY WORK 



HAVE BEEN A CONSTANT INSPIRATION 



THIS VOLUME IS AFFECTIONATELY DEDICATED 



