4 SIERRA DE UMANGO 
from the mouth of every „quebrada“ into the valley floor outside i 
the mountains. The rugged topography of the area, often a veri- 
table „Bad Land“, is doubtless the result of the intense, but spora- 3 
dic work of the named „crecientes“. 
The day-temperature is generally high all the year round. During 
the wintermonths the thermometer often reaches 20° C, resulting from 
the intense insolation. The nights are cold with 10° and more © 
below the zero. On heights ab. 4,000 m the temperature is generally 
low even at daytime, because the icy ,zonda“ never ceases to blow. 
Running waters are, except the sporadical ,crecientes“, extremely 
scarce in the Sierra de Umango area. Over the sandy bottom 
of the Guandacol valley the little Rio Bermejo is meandering 
southwards to the bolsons in the province of San Juan (see below, 
page 120) farther south. This river receives from the left hand an 
insignificant tributary, the Rio Vinchina, coming from the broad - 
valley, which separates the Sierra de Umango from the Nevado de - 
Famatina. Its upper course is draining the Jolson of Jaguel through 
the water gap opposite the Vinchina settlement. Both rivers are 
speeded by underground waters, and a source can hardly be fixed. 
All the mountain valleys and gorges are dry. 
A continuous vegetation is never to be seen, except the ,pasto- 1 
rales on great heights, where a hard grass grows, serving as food to — 
the cattle. The ,barrancas“ in the dry valley trains are sometimes ° 
bordered by algarrobo trees („gallery woods“), indicating the course 
of the underground waters. In the immediate vicinity of the water 
springs, generally scarce, and occuring either at the foot of a moun- 
tain or on the bottom of a ,quebrada“, there grows a high grass, — 
called by the natives „carrizales“. The open plains of alluvial gra- 
vel, sand and loess are dotted by xerophil thorn-bushes and various 
kinds of cactus. The most characteristic form of the northwest- - 
argentine deserts, the giant cactus (cereus giganteus), is completely — 
lacking in the Sierra de Umango area; it does not extend westward _ 
from the Nevado de Famatina. 
Sir Od ey eee ar 
