80 J. C. BRANNKK GEOLOGY OF NORTHEAST COAST OF BRAZIL 



they were shales and sandstones, while others are schistose or gneissic. 

 They are much jointed and but a little wrinkled, and stand at high 

 angles, 70 to 80 degrees, with a south (?) dip. In places they appear to 

 be crushed, and faulted. 



Between Russinha and the tunnels the cuts nearer the station expose 

 rather darker, more micaceous, and more decomposed rocks than those 

 higher up the mountains. From near the top of the mountain there is 

 a magnificent view toward the northeast and overlooking the hilly 

 valley of the Capibaribe. Between the summit and Rio Ipojuca are 

 some exposures of pinkish colored shales. After passing the divide of 

 the Serra da Russa there is but a slight descent to Gravata station, on 

 Rio Ipojuca, in the bottom of the valley to. the south-west of the moun- 

 tain. Thus the Ipojuca at this station is not in a valley like that at 

 Victoria or at Escada, but it flows through a wide, open, flat valley near 

 the edge of a mountainous plateau having an elevation of 500 meters or 

 more above the sea. 



Two hundred meters east of Gravata station (kilometer 89 ; eleva- 

 tion, 446 meters) there is a good exposure of the shales in a long shallow 

 cut. These rocks are clearly bedded, and some of them have the appear- 

 ance of altered silicious sediments like novaculites or diatomaceous 

 shales. Under a microscope of low power they seem to be filled with 

 elongated or lens-shaped grains of quartz or opal. They have a south 

 dip of about 70 degrees. 



The mountains seen south of Gravata have exposures of bare rocks 

 abftut their summits. Three hundred meters west of Gravata, again H 

 kilometers west of Gravata, and again 3 or 4 kilometers west of the same 

 station are cuts along the railway, in which bedded rocks — schists or 

 shales — are exposed with high (70 to 80 degrees) south dips. 



A belt of gneiss-like, dark banded rocks, 2 or 3 kilometers wide, fol- 

 lows. From 1 to 2 kilometers east of Bezerros station and south of the 

 river schistose rocks are exposed mostly with a south dip. There are 

 several bosses and exfoliated masses of gneiss just east of Bezerros. At 

 several places waterworn pebbles are exposed along the railway, but 

 these exposures are all near the Rio Ipojuca. At Bezerros (kilometer 

 112; elevation, 459 meters) a cut in the rocks opposite the station ex- 

 poses hornblende-schists crossed by large veins of pink feldspar. These 

 schists- have a south dip of only about 30 degrees. 



South of Bezerros the Serra Vermelha is in full view. It appears to 

 rise about 200 meters above the plateau. Bare rocks are exposed here 

 and there over its sides, resembling granite or gneiss bosses. Dombre 

 reports a bed of hematite iron ore in the Serra Negra, 2 leagues north 

 of Bezerros. 



