Waring: Geology of Northeastern Brazil. 215 



The foregoing notes on places where quartzite or crystalline lime- 

 stone were seen, indicate that these members of the Ceara Series are 

 widely distributed, though, where present, they cover only small 

 areas. Whether the schists, which probably constitute the greater 

 part of the series, are also limited to relatively small patches or belts, 

 or whether they form the bed-rock throughout a large part of the re- 

 gion, is a question which involves their definite recognition and 

 separation from the similar materials of the crystalline series. 



The Granites. 



In his reconnaissance in the northern part of the region under con- 

 sideration Crandall recognized that the granites are intrusive in the 

 gneiss and schists, and he observed that the principal granitic masses 

 trend northeast-southwest.^* SmalP^ has called attention to the 

 seeming gradation of gneiss into granite on the one hand and crystalline 

 schist on the other. He also notes that granite seems to be found 

 chiefly in the crystalline schists, rarely in the argillaceous schists (of 

 the Ceara Series).^" The only place in which he observed granite 

 intruded into the series seems to have been along the Riacho dos 

 Porcos, in the extreme southern part of Ceara. ^^ 



Most of the bare, isolated hills, like those shown on Plate VI, fig. 2 

 and Plate VII, fig. 2, are of granite, chiefly of gray, medium-grained 

 material; but in a few places pink or red granite has been observed, 

 and coarsely porphyritic phases have been noted. Granite to the 

 southeast, also northwest of Cratheus, may be described as a pink 

 porphyr}'. Along a narrow zone westward from Campos Salles to 

 Jaicos and thence southward to Simoes, Small found pinkish granite. ^^ 

 Dr. Branner noticed red "Scottish granite" along the railroad west of 

 Caruaru (136 km. west of Recife).'*^ Rock which contains feldspars 

 fully three centimeters in length is crossed by the railroad south of 

 Prudente de Moraes (258 km. south of Fortaleza), and similar coarsely 

 porph\'ritic rock is present at the southern base of Serra da Barriguda 

 near Jerico. 



^* PubL No. 4 of the Inspecloria, pp. 23 and 26. 



^^ PubL No. 25 of the Inspecloria, p. 38. 



^0 PubL No. 25 of the Inspecloria, p. 41. 



■*' Idem, Lac. cil., p. 41. 



^2 PlibL No. 32 of the Inspecloria, p. 73. 



^5 Geology of the Norlheasl Coast of Brazil, p. 81. 



