ALLUVIAL DEPOSITES. 35 
was crossed by Major Emory, its width was about twenty-five yards, and its deepest part just 
up to the hubs of the wheels. In that vicinity the river deflects slightly to the east, leaving a 
plain between it and the bluffs on the west side. This plain is sandy, destitute of wood, and 
has but little grass upon it. 
Mr. Marcou observes, under date of October 5, that the valley of the river widens considerably 
between Alameda and Albuquerque, and consists of sandy alluvium similar to that seen above. 
Sand-dunes were also found at this point, extending parallel with the valley. When he trav- 
elled eastward towards the Pass of San Pedro and the Sandia mountain he crossed the plain of 
the Rio Grande valley, and notes that for ten miles he travelled on the alluvions of the ** Rocky 
mountains." ! In this distance he doubtless traversed not only the river alluvion, but the 
detritus or wash from the granitic rocks of the Sandia range, which forms a broad and gradual 
slope. ; 
The valleys of the tributaries of the Rio Grande in that region appear to have a similar sandy 
and arid character. Lieutenant Abert observes of the valley of the Puerco, that it is wide and 
flat, overgrown with varieties of artemisias and coarse grass, fit only for sheep and goats. The 
banks of the river are of stiff loam. The country around is very much broken with sand-hills. 
The valley of Jemez river was also found to be sandy ; and this is the character of the banks 
of the Galisteo. ? 
1 Meaning probably the Santa Fé mountains and ranges in that vicinity. 
Abert’s Report on New Mexico. 
