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.3 



Sierra de Charagua, there 

 are several massive beds 

 of variegated calcareous 

 sandstone. In some of 

 these beds the grains of 

 sand are not in contact 

 with each other, but are 

 merely thickly scattered 

 through the calcareous 

 rock. These two forma- 

 tions are believed to be 

 equivalent to each other 

 and to the cherty limestone 

 at the type locality of the 

 Vitiacua formation, al- 

 though this correlation is 

 by no means a sure one. 



Wherever observed, the 

 Vitiacua limestone and 

 chert is structurally con- 

 formable with the under- 

 lying beds of the Bermejo 

 series and with the over- 

 lying Tacuru formation. 

 There is, however, an im- 

 portant stratigraphic break 

 between the Bermejo and 

 Tacuru formations, as in- 

 dicated by conglomerates 

 in the latter, which are 

 formed of pebbles and 

 tahis fragments derived 

 from the former. The 

 limestone and chert at the 

 type locality in the Vitia- 

 cua gorge is the same for- 

 mation as that to which 

 Steinmann has applied 

 the name "Horizonte Cal- 

 careo - dolomitico." Al- 



