STRUCTURAL FEATURES ALONG SAO FRANCISCO RAILWAY 71 



Between Canhotinho and Angelim bosses of crystalline rocks are ex- 

 posed here and there over the campos, and the surfaces show numerous 

 veins of quartz and dikes of pegmatite. 



About 5 kilometers west of Canhotinho schists dip south at an angle 

 of 50 degrees. A little farther west there are exposed soft bedded rocks 

 resembling sandstones. Still farther west are schists dipping south 25 

 degrees west 60 degrees. 



Three hundred meters west of Angelim (kilometer 242.7 ; elevation, 

 647 meters) are granites and crystalline schists. 



Between Angelim and Sao Joao there is a line of hills south of the 

 railway, about 100 meters above the railway level, in which the rocks 

 appear to be bedded and to dip north at an angle of about 30 degrees. 

 In the railway cuts the exposures show the schistose rocksTor a distance 

 of 2 or 3 kilometers to dip southwest at an angle of about 45 degrees. 

 These rocks are cut by many veins. 



At Sao Joao (kilometer 253.5 ; elevation, 699.9 meters) crystalline 

 schists are exposed in the cut just west of the station. They clip 

 northeast. 



The rocks at and about Garanhuns are all either gneisses or granites. 

 Most of the surrounding plateau, however, is covered by the products of 

 the decomposition of these rocks. 



TOPOGRAPHY OF THE REGION 



Some of the topographic features of the region traversed by this rail- 

 way are worthy of attention. The plateau on which Garanhuns (eleva- 

 tion, 866 meters) stands has an elevation of a little more than 1,000 

 meters at its western rim at Poco, about 35 kilometers west of the town * 



At the west of Cimbresthe — . 



plateau is said to rise more 

 than 1,000 meters above 

 sealevel. The streams that 

 head in this high region 



, . Figure 10. — Profile of the Hills South of Glyceno. 



have cut their valleys m 



this plateau to a depth of 400 and 500 meters. There are no longer 

 mountain chains over the plateau, but neither is the sky-line, as seen 

 from the hills about Garanhuns, a flat or even one. The upper portions 

 of the valleys are rather narrow and steep-sided. 



South of the railway between Garanhuns and Sao Joao the following 

 is the profile of the highest hills. These hills are only from 100 to 150 

 meters high south of the railway half a kilometer from Sao Joao. 



* Doctor L. Lombard. 



