322 
VALLEY or THE EIO BEL NOETE. 
knot, or widening of tlie Cordilleras, is that the groupinn- of 
tlie sunmits is independent of the general direction of the 
axis, ihe backs of the mountams in JMew Spain form very 
carriages can roll for an extent 
ot 400 leagues from the capital to Santa-I’e and Taos, near 
the sources of liio del Norte. This immense table-land, in 
constantly at the height of from 950 to 
1200 toises, that is, at the elevation of the passes of the 
Great Saint Bernard and the Spliigen. We find on the 
back of the Cordilleras of Anahuac, which lower progressive^ 
from the city ol Me.xico towards Taos, a succession of basins: 
they are separated by hills little striking to the eye of the 
Iraveller because they rise only from 250 to 400 toises above 
1 he surrounding plains. The basins are sometimes closed, 
ike the valley of Tenochtitlan, where he the great Alpine 
lakes and sometimes they exhibit traces of ancient elections, 
destitute of water. 
Between lat. 38“ and 38°, the Eio del Norte forms in its 
upper course, a great longitudinal valley; and the central 
Cham seems here to be divided into several parallel ranges. 
I his distribution continues nortliward, in the Eocky Moun- 
tains,* where, between the parallels of 37° and 41'^ several 
summits covered with eternal snow (Spanish Peak, James 
1 f to 1870 toises of abso- 
lute height. Towards lat. 40° south of the sources of the 
Paduca, a tributary of the Eio de la Plata, a branch known 
by the name of the Black Hills, detaches itself towards the 
north-east from the central chain. The Eockv Mountains 
at first seem to lower considerably in 46° and 48° ; and then 
rise to 48 and 49°, where their tops are from 1200 to 1300 
toises, and their ridge near 950 toises. Between the sources 
of the Missouri and the Eiver Lewis, one of the tributaries 
of the Oregon or Columbia, the CordiUeras form in widening 
an elbow resembhiig the knot of Cuzco. There, also, on the 
eastern declivity of the Eocky Mountains, is the partition of 
water between the Caribbean Sea and the Polar Sea This 
point corresponds with those in the Andes of South America, 
at the spur of Cochabamba, on the east, lat. 19® 20' south ; 
different periods designated by 
lnrsrd;:4unS:r“’^“’ stonyf shining! 
