AF 
HISTORICAL REVIEW ' 9 
In still later time Dr Walther Penck, formerly geologist of the 
Direction of Mines, at present professor of geology at the University of 
- Leipzig, Germany, has investigated the area of the Bolson de Fiam- 
_ bala and surrounding mountains, lying in the province of Catamarca 
_ and in the NE continuation of the Sierra de Umango complex. The 
results of these works are: a geological map in the scale 1: 200,000, 
preliminary reports (1914/15) and a complete geological-morpholo- 
_ gical monography (1920) of „the southern border of the Puna de 
_ Atacama“, as he names the region. 
The main results of W. Penck may not be mentioned here, 
because in the following pages it will be various occasions to return 
to his works. It may only be stated here, that the peculiar ban- 
ded structure of the Sierra de Umango metamorphic series is 
continuing far into the Catamarca mountains and that the conti- 
nental overlapping strata show a great similarity to the La Rioja 
beds. 
Simultaneously with my own camp works in the Sierra de Umango 
area, my colleague Dr Juan Rassmuss was carrying on an inves- 
tigation in the adjacent part of the „Precordillera“ to the W and 
SW from the Sierra de Umango. The result of Rassmuss is 
_ hithertoo, so far as I know, a handcolored geological map. His verbal 
communications have been to great use for my own purposes. 
