590 APPENDICES. 
any branch of that river, then to the point on the said line nearest to 
- such branch, and then in a direct line to the same”). 
This portion of the line can only be ascertained by examinations and 
surveys upon the ground. You will, however, receive important aid in 
the determination of this line, as the treaty expressly declares that “ the 
southern and western limits of New Mexico, mentioned in this article, 
are those laid down on the maps of the United Mexican States, published 
at New York in 1847, by J. Disturnell,” a certified copy of which was 
appended to the treaty, bearing the signatures and seals of the plenipo- 
tentiaries. You are furnished with a certified copy of this map. 
The remainder of the boundary runs along the middle of the River 
Gila and the Rio Grande; of the former, from the point where the west- 
ern line of New Mexico intersects it to its junction with the Colorado ; 
and the latter, from the point intersected by the southern line of New 
Mexico near El Paso, to its mouth. 
As the organization of the Commission under your charge has been 
made for the purpose of collecting information relative to the country 
contiguous to the boundary line, in addition to the running of that line, 
it is desirable that you should avail yourself of every opportunity afford- 
ed by your passage through the unexplored regions of Texas, New Mexi- 
co, and California, to acquire information as to its geography, national 
history, &c., when it can be obtained without retarding the progress of 
the boundary survey. You are, therefore, at liberty to send out explor- 
ing parties, when not otherwise employed on the survey of the line, to 
examine the country north of the Gila, as well as on either side of the 
Rio Grande, for the above and kindred purposes. 
It is stated, on the authority of persons who have traversed the coun- 
try near the river Gila, that during a considerable portion of the summer 
there is neither grass nor water to be obtained. Should the Commis- 
sion be in this region at this season, it may be compelled to suspend its 
operations, In such an event, your party may be usefully employed in 
geographical and scientific explorations in the regions before alluded to. 
The collection of information relative to the precious metals, quick- 
silver, and the various minerals, ores, and other substances, useful in the 
arts, is very desirable. In reference to the existence and localities of 
these, as well as the locations of mines formerly worked by the early set- 
tlers in California and New Mexico, and since abandoned, owing to the 
incursions of the Indians, or other causes, you will do all in your power 
