68 SIERRA DE UMANGO 
and triassic beds are united by him under the denomination „Pa- 
ganzo strata‘. In this group, lying generally in concordance, except 
the Precordilleran zone, and being wholly of continental character, 1 
Bodenbender distinguished between three subdivisions of quite 4 
different habit: „Piso“ I, II and III. The conformable hanging strata ° 
he considered as rhaetic, jurassic and cretaceous, the last named 
being in the subandean regions of coarse detritic, in extra-andean - 
(pampean) areas of calcareous habit. j 
Regarding the Sierra de Umango area, a similar stratigraphical ° 
division will hardly be applicable, because of the many breaks in i 
the succession of the strata caused by tectonical tearings and also : 
because of the extreme scarceness of fossils. Stappenbeck al- I 
ready met with the same difficulties in the Precordillera (between 
Mendoza and Jachal). In similar circumstances worked also more 
recently W. Penck in the province of Catamarca, or nearer said 
in the region of the valley of Fiambala (1920). | 
In the following pages there will be communicated a more detai- ° 
led description of all important occurrences of the continental strata, 
and then the writer makes an attempt to divide the whole series 
on the basis of lithological, stratigraphical and tectonical relations. 
a) DESCRIPTION OF LOCALITIES. 
The Cerro Guandacol (The southern part of the Cerro Villa Union). 
The most complete and most representative profile; through the 
lower part of the continental series is exposed here, especially on 
the abrupt western side of the mountain, some miles to the east of 
the village of Guandacol situated on the river La Troya.t The 
westfacing slope is due to a great fault, running at long distance ~ 
in a north-southerly direction along the eastern border of 
the valley of Rio La Troya (Rio Bermejo). The profile of the 
Cerro Guandacol was described at various times by Bodenben- 
1 See the profile fig. 7. 
ee NM 
