114 GENERAL REMARKS ON THE TOPOGRAPHY. 
sidered a matter of importance, as being in accordance with some supposed laws of mountain 
formation, but that of centres of upheaval are not less consistent with those laws. At any rate 
it does not appear that we are at liberty to assume a parallelism of ridges till examination has 
shown this to be the case. 
As many of the lines of explorations in the mountains have been conducted along lines run- 
ning east and west, leaving unexplored spaces between them, much ingenuity and skill has 
been bestowed in attempting to determine the continuations of ranges between the routes. 
Leaving out of view the fact that they may not be continuous, the effort has been made to 
determine the continuity by prolonging their directions. This assumes a degree of accuracy 
in the relative geographical position of the supposed parts which they may not have. There 
is generally too little known of the mineral constituents of each portion to settle the question 
on geological principles. The result of these arrangements have therefore been of little utility, 
while they have confused the nomenclature by extending local names beyond their proper 
limits. Of this confusion the Sierra Madre is a striking example, as will appear from the fol- 
lowing quotations : 
Humboldt, in his work on New Spain, says: ‘To the north of the 19th parallel of north lati- 
tude, near the celebrated mines of Zimapam and Doctor, the Cordillera takes the name of Sierra 
Madre; it runs to the northwest, towards the towns of San Miguel el Grande and Guanaxuata. 
To the north of this last city the Sierra Madre assumes an extraordinary width. It soon 
separates into three branches, of which the easternmost loses itself in Leon; the western branch 
extends northwesterly towards the Gila, through Sonora. The third T of the Sierra 
Madre, which may be looked upon as the central chain of the Mexican Andes, occupies the 
whole of Zacatecas. It may be traced to the Sierra de los Mimbres; thence it crosses New 
Mexico, and joins the Crane mountains and Sierra Verd. It is the crest of this central branch 
of the Sierra Madre that divides the waters of the Pacific Ocean from those of the Gulf of 
Mexico. It is the continuation of this which Fidler and the intrepid Mackenzie examined 
from the 50th to the 55th parallel of north latitude.” 
Mr. Albert Gallatin writes, in a communication to Lieutenant Emory, (Ex. Doc. 41, Ist 
session 30th Congress: “I use the word Sierra Madre in the sense attached to it by the 
Mexicans, viz: that ridge which separates the waters that fall into the Atlantic from those that 
empty into the Pacific, without reference to its elevation.” 
Lieutenant Simpson, in his report of his expedition to the Navajo country, says, in speaking 
of the Sierra de los Mimbres or Sierra Madre: ‘‘ Our exploration shows that, instead of its exhib- 
iting, in transverse section, the sharp angles of the primary mountains, or the flat table-shaped 
aspect of the mesa formation, it presents more strictly the outline of a formation"! in — 
“the country intervening between the far distant escarpments"! is **considerably convex.’ 
: Mr. Froebel, in his report published by the Smithsonian Institution in 1854: “I come now 
to speak of the Sierra Madre. This denomination has been the cause of many geographical 
misunderstandings and misconstructions. .It has been understood as a real proper name, while 
it is but an appellative meaning the mother chain of mountains, û. e., the principal chain of a 
country in general, just as the Mexicans call Acequia Madre the pind pal channel of a system 
of irrigation. Thus the name may occur in different localities without thereby authorizing 
geographers to conclude that all the mountain chains which have received that denomination 
belong to one and the same system. It may therefore really be, as some maps haye it—I do not 
know from what source—that a certain chain east of Durango, belonging to the line of ridges 
