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PROFESSOR LOUIS AGASSIZ [ 
HARVARD -UNIVERSITY, CAMBRIDGE, MASSACHUSSETTS. i, 
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My dear Sir, 
You had the kindness, in 1853, to allow me to dedicate to you, my first slight sketch of A Geo- 
logical Map of the United States, published at Boston, in July of that year; I now offer you a second 
part of that work, completing the first, and giving an outline of the Geology of the Rocky Mountains, 
the Sierra Madre , and California. 
After my return from the « Pacific Railroad Exploration » , you expressed your satisfaction with my 
manuscript maps and my specimens , and , after the publication of my Resume Explicatif dune Carte Geo- 
logique des Etats—Unis , in the Bulletin de la Societe G4ologique de France, you said to me in one of your 
letters , dated Cambridge , 10 Feb. 1857 ; « Vos combinaisons sur les rapports des terrains de I'Amerique du 
«Nord sont ce qu’il y a de mieux sur la Geologie des Etats-Vnisn. You will excuse my bringing forward 
so favorable a Judgment, but you are better able than any one to appreciate Justly the value of a geo- 
logical work on North America. 
I send you this little work from a place where you began your University education, more than 
thirty years ago , and where you are far from being forgotten. At the foot of the Utliberg , between the 
Alps and the Jura, in this beautiful valley of Zurich, there are still many of your class mates, and I can 
hardly meet a gentleman without being asked about you and your life in America. Since you left 
