IMRODUCTION. 
7 
of this work. If Mr. Blake had practically studied on the spot, the geology of the British Provinces, 
the Southern and Western States, the Prairies, the Rocky Mountains, Texas and New Mexico; 
1 should understand in a degree a part of the criticism contained in his pamphlet. But having in 
his hands my note-hooks, that had been forcibly taken from me, without my being able to use 
them; being reduced to my memory, my private journal, and the letters 1 had written, it is rather 
strange that Mr. Blake should reproach me with not having made a good use of the means at my 
disposal; and I think all impartial geologists will agree, that the Secretary of War Mr. Davis, in 
giving my note-books and specimens to Mr. Blake, did not give them into friendly keeping, nor 
to a geologist of great practical experience. 
I repeat then, that I decline all responsibility as to the use that may have been , or may here- 
after be made by others of my official note-books and specimens , which for me have no existence ; 
and I recognize as my productions only the two Rhumbs published with my signature in the octavo 
edition of the Pacific Railroad Explorations, Washington, 1855; reports that I give here verbatim, 
with the addition of notes and a Chapter of Paleontology. 
With the help of my private journal and several letters written during my stay in New Mex- 
ico , I have been able to give a sketch of the Geology of that Territory under the form of a daily 
journal. The situation of New Mexico, a sort of oasis in the midst of the American desert, ren- 
ders it a central point for the Geology of the New World, and as such deserves particular notice ; 
and as explorations are rendered doubly difficult , by the barrenness of the country and the terrible 
and treacherous tribes of Comanche, Apache et Navajo Indians, some years may pass before another 
Geologist enters that part of the United States. For these reasons my work and map although very 
imperfect will perhaps be received with some interest by persons occupied with the study of Geo- 
graphical Geology. 
The extremely short Resume in explanation of the Geological Map of the United States and the 
British Provinces, was published in German with the title: Vber die Geologie der Vereinigten Staatenund 
der Britischen Provinzen von Nord-Amerika , in July 1855, in the 6"’ number of the first volume of Geo- 
graphischen Mittheilungen o! Dr. A. Petermann, and is only an extract from a much larger work pub- 
lished in March 1856 in the „ Bulletin of the Geological Society of France; meeting of the 21®* of 
May, 1855; vol. XU., second series", entitled «Raumd expUcatif d'me Carte GMogique des Etats-Vnis 
et des Provincee Anglaises de tAmirique du Nordy>. A work in which I introduced all the discoveries 
made during my exploration of the Rocky Mountains and the Sierra Nevada, and which gives for 
the first time a complete Geological Map of the United States and British Provinces of North Ame- 
rica, and was the first attempt at a geological description of the whole of this vast country. 
Some strange notions upon the geological discoveries that have been made in America, and 
some facts quite distorted and misrepresented, having found admittance into several works, espe- 
cially an address: On American geological history , by James D. Dana, president of the American As- 
