Chap. VIII. SIERRA MADRE. 555 
tain-chains of the Sierra de Guadalupe and Sierra del 
Diablo belong to the same chain. South of the Presidio 
del Norte, in the vicinity of San Carlos, the latter meets 
again the Rio Grande, and crosses it from its eastern 
to its western -side, the river making here a great bend to 
the east in a long and narrow defile, with a series of falls. 
This is the point at which the Rio Grande descends from 
the middle section of its course which still belongs to the 
table-land, into the lower plains of the Mexican Gulf. 
This range, however, forming the eastern boundary of the 
Bolson de Mapimi, extends farther south, through the 
Mexican States of Cohahuila, Nuevo Leon, San Luis 
Potosi, and Vera Cruz, where it forms the eastern edge of 
the plateau of Anahuac. 
Y. — I pass on to the Sierra Madre — a name which has 
led to many geographical errors. The appellation is, 
strictly speaking, no proper name, but signifies in general 
the principal mountain-range of a country — literally, the 
" Mother-mountain," just as the Mexicans call the prin- 
cipal canal in a system of irrigation the Acequia Madre, 
or " Mother-canal." The name is thus found in various 
places, and the geographer would be in error to infer 
that the different chains of the same name belonged to one 
and the same system. If there exists a mountain-chain 
under the name of Sierra Madre, belonging to the above- 
described range of the southern continuation or southern 
equivalent of the Rocky Mountains, as laid down on the 
maps to the east of Durango, this is quite independent of 
the great Sierra Madre, which marks the western border 
of the Mexican plateau towards the lower country of 
Mechoacan, Jalisco, Cinaloa, and Sonora, and across which, 
to the west of Durango, passes the road from this town to 
Mazatlan. A third Sierra Madre is mentioned in New 
