2 
INTRODUCTION. 
from the Rio Grande to Preston) an invitation to make a geological report upon his route. I 
had had the pleasure to make the acquaintance of Capt. Pope at Albuquerque, in October 1853, 
and as he had then received the order to make his exploration , and was in New Mexico , a country 
where geologists are unknown , I had given him verbal instructions on the manner of making col- 
lections of specimens and taking geological notes, promising him my cooperation for the geological 
part of his report. I undertook with pleasure the preparation of the geological report of Capt. Pope, 
and after a rapid examination of his fine collection , I sent him a geological Resume which he wished 
to place at once in the octavo edition. 
Having packed all my collections, books and other effects, and taken and paid my passage 
and that of my family consisting of four persons, on the Cunard Steamer Niagara-, I was leaving 
my residence in Boston at nine o’clock in the morning the 27“'* September in order to embark, the 
steamer leaving the Wharf at East-Boston at noon, when I received letters from Captains Whipple 
and Pope containing orders from the Secretary of War to remain in the United States, or to give 
up my notes. The following are extracts from these letters. 
My dear Marcou , 
Washisgtos (District of Columbia) , September the 25*’’ 1854. 
I have just received a communication from the Secretary, objecting in the most decided terms to 
allow your notes to be taken out of the country. He says the report must be completed here and wishes 
you to remain in the United States until it is finished. I know the inconvenience this must put you to 
at so late a period, when your arrangements for leaving America are consummated. But I can only ex- 
press my deep regret, and ask you to submit to the sacrifice if your health will permit you to do so. 
Etc. Etc. . . . 
Truly your friend 
(Signed) A. W. WHIPPLE, 
first Lieut Top. Eng. Corps U. S. A. 
Mr. Jules Marcou 
Boston (Massachussetts). 
Dear Sir, 
Washington (D. C.) , September the 25*** 1854. 
The Secretary of War has come to a determination which it is not worth while to discuss as it is 
conclusive so far as the officers of Pacific Railroad parties are concerned. 
He insists that the report on Geology shall be made out in this country, and in consequence I find 
myself most unexpectedly and at this late hour compelled to notify of a conclusion as disagreeable to 
me as it can possibly be to you. 
There is no one in the country, from the peculiar circumstances, who can do justice to the geolo- 
gical reports of the Surveys of Whipple and myself, except yourself, and I earnestly' hope that you can 
be induced to remain. If you find it impossible to do so however, I am compelled to ask you to re- 
