PREFACE. xi 
graphic work ; the final maps will exhibit the results of his learning and 
executive ability. 
Professor Joseph Henry, the Secretary of the Smithsonian Institution, 
under whose direction the work was performed, prior to* the 1st of July, 
1874, has contributed greatly to any success which we may have had, by 
his instructions and advice, and by his most earnest sympathy ; and I have 
taken the liberty to express my gratitude for his kindness, and reverence 
for his profound attainments, by attaching his name to a group of lofty 
mountains. 
To the officers of the Union Pacific, the Chicago, Burlington and 
Quincy, the Utah Central, and other railroads, I am indebted for many val 
uable favors; but for their co-operation the work could not have been 
accomplished with the means at my command. Many thousands of dollars, 
in the aggregate, have been contributed by them to the enterprise in the 
form of free transportation. I earnestly hope that the final result of the 
work, as a contribution to American science, will not disappoint their expec 
tations. 
J. W. P. 
WASHINGTON, D. C., 1875. 
