J. G. Branner — The Tomhador EHcarjpment. 339 



present trail, the false beds are often three or four meters high. 

 The general dip of the beds themselves is gentle and toward 

 the north. At other places the dip is toward the west or 

 northwest, but it is always in the direction of the Salitre valley, 

 of which this range forms the eastern rim. The top of the 

 range is a beautiful open grassy campo, whose surface dips 

 west at an angle of four degrees. Five or six kilometers to 

 the west these grass-covered eampos merge into the catinga 

 forests that cover all the rest of the Salitre valley. 



Going westward or northwestward down the slope of the 

 range one passes from the Tombador sandstones to a series of 

 whitish flinty beds that the writer has called the Jacuipe flints. 

 These flinty beds seem to overlie the Tombador sandstones 

 conformably. They are well developed in that part of the 

 range locall}'- known as the Serra da Gamelleira and along the 

 southern third of the Tombador range proper. At the fazenda 

 do Pogo close to the crest of the serra they have a measured 

 thickness of twenty-seven meters. This, however, is not the 

 total thickness of the flints, for the upper portion of the beds 

 has been removed by denudation. 



Thus far no fossils have been found in the flint beds, but at 

 many places the rocks have an oolitic structure. Where they 

 have weathered out on the surface they are often of a light 

 gray color. This gray color is characteristic of the flints over 

 much of the Serra da Gamelleira and over the southern end of 

 the Serra do Tombador, but further north in the latitude of 

 Campo Formoso they are yellowish, brown and red. Follow- 

 ing the trail from fazenda do Po§o toward Catinga de Moura, 

 the upper limit of the Jacuipe flints is four or five kilometers 

 northwest of the crest of the serra. 



Next above the Jacuipe flints and resting conformably upon 

 them is a series of shales that were given the field name of 

 Caboclo shales from their development in the Serra do Caboclo 

 op the west side of the Salitre valley. These shales vary con- 

 siderably in color and thickness, but the exposure of them at 

 this particular place cannot be regarded as typical or especially 

 good. On this western slope of the Serra do Tombador these 

 shales where exposed on the road are thin-bedded ; the lower 

 beds are of a light brown color, while the upper ones are light 

 gray to nearly white with some tine-grained sandstones interbed- 

 ded with them. The thickness of the shales here is estimated 

 to be between 45 and 90 meters. The same shales are well 

 exposed in the gorge in the lower edge of the town of Ventura, 

 where they are of a yellowish and greenish gray color, jointed 

 and flaggy, and have a gentle western dip. In the b'lufEs at 

 Ventura these shales strongly resemble the flaggy Cayuga shales 

 at Ithaca, New York. Although the Caboclo "shales have been 



