2 aoe 
66 SIERRA DE UMANGO 
Colorado and vicinity, on the eastern side of the Cerro Villa Union. — 
Here the plane is uplifted partly to a relatively high position and 
has a SE dip. In the through-going Quebrada Banda Florida far- 
ther to the north the plane forms the bottom of the quebrada and 
is overlaid with red sandstone. 3) Cerro Potrero Viejo, southern 
part. Here the plane is quite broken, but seems to dip in a sou- 
therly direction. Lower Gondwana lies over it with a thin basal 
conglomeratic layer. 4) Sierra de Safiogasta, southern part of the 
Nevado de Famatina. The plane rises to great heights from south- 
east in the direction of the summit of the Nevado, appearing as 
an even crest line. It is, hovewer, somewhat doubtful, if this plane 
can be regarded as an equivalent to the former, because the age 
of the overlying red sandstone still conserved in some parts of the 
crest is uncertain. | 
B) THE CONTINENTAL SERIES. 
Gondwana [Paganzo (La Rioja) stratal — upper meso- 
zoic and lower tertiary beds. 
Detritic sediments in perfect conformity. 
According to geological maps! of the central western Argentina 
the areal distribution of the continental sediments, lying over the 
pampean — partly sunken and partly uplifted — crystalline basement, 
is varying in different parts of the region. While the outcrops of 
these clastic rocks in the more eastern parts as in the Sierra de 
Cordoba are insignificant, their extension increases gradually, when 
approaching the border of the Cordillera. The tectonical appea- 
trance of these series in the region of the „Sierras pampeanas“ 
is in general such: Along the border of the horst-blocks (the Sier- 
ras) they form an outward dipping fringe, an erosion remnant of 
1 Ludw. Brackebusch: Mapa geolögico del interior de la Republica Argen- 
tina. Scale 1:1,000,000. Gotha 1891. 
G. Bodenbender (1911). 
