MO J. G. Branner — The Tomhador Escarpment. 



examined at a o;i-eat many jilaces and over large areas, no fos- 

 sils of any kind have yet been found in them. 



Next above the Caboclo shales is a series of sandstones which 

 are believed to be the Lavras series of Derby.* .The contact 

 between the shales below and the sandstones above is not well 

 exposed at this place, but in the zone of the contact, and espe- 

 cially where the lowest part of the sandstones has been removed 

 by denudation, there are many heavy water-worn bowlders 

 scattered over the surface as if they had originally formed part 

 of a basal conglomerate. Some of these bowlders are as much 

 as two feet in diameter. 



These Lavras sandstones form a series of low hills rnnning 

 parallel with the Tombador range. At this place they are 

 only from twenty to one hundred and fifty meters high, that 

 is above the general level of the plain immediately about them. 

 Though they can be traced for a long distance with the eye, it 

 seems probable that they occasionally disappear altogether. 



The road leading to Catinga de Moura from Jacobina was 

 not followed further west than this range of hills formed by 

 the Lavras sandstones. What the next overljang rocks are at 

 this particular place cannot be positively stated from pei'sonal 

 observation. A little further toward the northwest on the 

 Engeuho estate the rocks are limestones, and it is a matter of 

 common information that the rocks at Catinga de Moura are 

 limestones. Over the surface of the ground near the base of 

 the Lavras beds fragments of the pinkish limestone so common 

 along the Rio Salitre were found. It is, therefore, inferred 

 that the limestone not only overlies the Lavras sandstones, but 

 that it even encircles and passes to the east of the ridges made 

 by those sandstones. Such relations are borne out by observa- 

 tions at other places in the Salitre valley. 



The sequence and thicknesses of the various series observed 

 in this section across the Serra do Tombador, as nearly as they 

 could be made out on the Jacobina-Chique Chique road, are 

 estimated as follows. 



Salitre limestone (not seen in place) 



Lavras sandstones 46 to 60 meters. 



Caboclo shales 45 to 90 " 



Jacuipe flints 20 to 30 " 



Tombador sandstone 90 " 



Granites and gneisses at base about 250 meters visible. 



Further north the sandstones and conglomerates that give 



character and prominence to the southern extremity of the 



Tombador range become less conspicuous in the topography. 



North of the Jacuipe watergap, however, they do not cease to 



*0. A. Derby, Economic Geology, i, 134-142, Nov.-Dec. 1905. 



