Latitude 18 1/2 to 19 1/2 degrees. Trachytic knot of Anahuac, parallel
with the Nevados and the burning volcanoes of Mexico.
Latitude 19 1/2 to 20 degrees. Knot of the metaliferous mountains of
Guanaxuato and Zacatecas.
Latitude 21 3/4 to 22 degrees. Division of the Andes of Anahuac into
three chains:
Eastern chain (that of Potosi and Texas), continued by the Ozark and
Wisconsin mountains, as far as Lake Superior.
Central chain (of Durango, New Mexico and the Rocky Mountains),
sending on the north of the source of the river Platte (latitude 42
degrees) a branch (the Black hills) to north-east, widening greatly
between the parallels 46 and 50 degrees, and lowering progressively as
it approaches the mouth of Mackenzie River (latitude 68 degrees).
Western chain (of Cinaloa and Sonora). Linked by spurs to the maritime
Alps, or mountains of California.
We have yet no means of judging with precision the elevation of the
Andes south of the knot of the mountains of Loxa (south latitude 3
degrees 5), but we know that on the north of that knot the Cordilleras
rise five times higher than the majestic elevation of 2600 toises:
In the group of Quito, 0 to 2 degrees south latitude (Chimborazo,
Antisano, Cayambe, Cotopaxi, Collanes, Yliniza, Sangay, Tungurahua.)
In the group of Cundinamarca, latitude 4 3/4 degrees north (peak of
Tolima, north of the Andes of Quindiu).
In the group of Anahuac, from latitude 18 degrees 59 minutes to 19
degrees 12 minutes (Popocatepetl or the Great Volcano of Mexico, and
Peak of Orizaba). If we consider the maritime Alps or mountains of
California and New Norfolk, either as a continuation of the western
chain of Mexico, that of Sonora, or as being linked by spurs to the
central chain, that of the Rocky Mountains, we may add to the three
preceding groups:
