84 ۱ EXPLORATIONS FROM A. D. 1852 TO A. D. 1857. 
The report of Major Emory was published in 1858, and forms Senate Ex. Doc. No. 108, 1st 
session 34th Congress, and, with the appendices, makes two volumes. There are four topo- 
graphical maps on a scale of 1 to 600,000, ‘‘showing the boundary line and the country 
contiguous, as far as information has been obtained from actual survey or reconnaissance." 
There is also a topographical map on a scale of 1 to 6,000,000, entitled a ** Map of the United 
States and their Territories between the Mississippi River and the Pacific Ocean and part of 
Mexico, compiled from surveys made under the order of W. H. Emory, major 1st cavalry, 
United States commissioner, and from the maps of the Pacific railroad, General Land Office, 
and the Coast Survey, projected and drawn under the supervision of Lieutenant N. Michler, 
Topographical Engineers, by Thomas Jekyll, C. E., 1851— 58." This map (of all the country 
north of the surveys of the Mexican boundary) is a reduction from the map which I have 
compiled for the Pacific railroad office. 
During the time I was engaged on this compilation, the Pacific Railroad office was supplied 
with information from the office of Mexican Boundary Survey, and in return copies of our com- 
pilation were furnished that office in advance of its publication. Major Emory's report is also 
accompanied by a geological map of the same country, and on the same scale as that just 
mentioned, prepared by James Hall, assisted by J. P. Leslie, esq. This map is without date. 
There is also a barometrical and geological profile along the Rio Grande from its mouth to 
El Paso, and thence across the country to the Pacific. The report contains numerous illustra- 
tions of scenery, and geological, botanical, and zoological plates. 
Assistance is acknowledged to have been received in the field from Lieutenant A. W. 
Whipple, Topographical Engineers, Brevet Captain E. L. F. Hardcastle, Topographical 
Engineers, Mr. G. C. Gardner, Dr. C. Parry, Messrs. E. Ingraham, C. Radziminski, Arthur 
Schott, J. H. Clark, S. W. Jones, E. A. Phillips, J. H. Houston, J. E. Weiss, H. Campbell, 
F. Wheaton, W. White, and G. G. Garner. 
The line, as finally determined and established under the treaty of Guadalupe Hidalgo, 
extended up the Rio Grande from its mouth to latitude 31° 54' 40” north; thence west along 
that parallel to the meridian of 109° 37’ west; thence due north to the Rio San Domingo; 
thence down that stream to the Gila; thence down the Gila to its mouth; thence in a straight 
line to the point on the Pacific, in latitude 32? 32' north. 
Numerous reconnaissances were made by different parties in going to and from various points 
on the line; and the Rio Grande was surveyed as far up as the parallel of 329 22’ north, and a 
portion of that parallel run by Lieutenant Whipple as directed by Mr. Bartlett, commissioner 
at the time. 
The treaty of 1853, by which the tract of territory known as the Gadsden purchase was 
acquired from Mexico, changed the boundary line so as to make it commence on the Rio 
Grande at latitude 31° 47’ north; thence due west 100 miles; thence south to latitude 
31? 30' north; thence due west to the 111th meridian; thence in a straight line to a point on 
the Colorado twenty miles below its junction with the Gila; thence up the Colorado to m 
former line. 
To establish this boundary Major Emory, (then brevet major corps Topographical Engineers, ) 
was appointed commissioner and astronomer on the part of the United States; and the work 
was accomplished during the years 1855-56. Major Emory was assisted in this work by 
Lieutenant N. Michler, Topographical Engineers, Lieutenant C. N. Turnbull, Topographical 
Engineers, Messrs. C. Radziminski, M. T. W. Chandler, J. H. Clark, H. Campbell, W. Emory, 
