388 



-/. C. Rranner — The Serra de Jacohina. 



general level. The mica schists are exposed on the road al)out 

 two and a half kilometers due south of Monte Tabor. The 

 qnartzites and other rocks of the Monte Tabor range, which is 

 the eastermnost member of the Jacobina range, all dip toward 

 the southeast at a high atigle. 



About twenty kilometers northeast of liio Agua Branca 

 another section across the Serra de Jacobina was examined on 



Fig. 2. 



Fig. 2. Sectiou across the Serra de Jacobina along Eio Campo Formoso 

 or Agua Branca. 



and in the vicinity of the road between Yilla Nova and Campo 

 Formoso. Tlie general structure on this road is shown in the 

 accompanying section (fig. 3). 



In this section the summit of the Morro da Mina has an 

 elevation of 950 meters a. t. or 403 meters above the railway 



Fig. 3. 



Fig. 3. Section across the Serra de Jacobina west of Villa Nova. 



station at Yilla Nova. A dip measured on Morro da Mina is 

 60° S. 40° E. magnetic. The rocks are the usual quartzites 

 more or less decomposed at many places, and red and purple 

 shales interbedded with them. 



The next section across this range to which attention is 

 called is west from the i-ailway station of Jaguarary and 

 twenty-five kilometers north of Villa Nova. The distance 

 through the i-ange at Jaguarary is about six kilometers on a 

 straight line, and about nine by the trail. The drainage does 

 not cut entirely through the range here as it does at Campo 

 Formoso and Jacobina. The rocks exposed at and about 

 Jaguarary are all granites. These granites are cut by the 

 railway at several places south .of the town, and they are well 

 exposed in bosses from thirty to fifty meters across. 



The serra at this place is made up of four quartzite ridges, 

 the three parallel valleys being cut in talcose schists similar to 



