186 Annals of the Carnegie Museum. 



Camocim and the southern terminus at Novilho, between Fortaleza 

 and Iguatu, and the coastal lines between Natal and Maceio. In the 

 southern area horseback trips were made in the basin of the Itapicuru 

 River, and the railroad lines between Bahia and Joazeiro, Bahia and 

 Joao Amaro, and Bahia and Feira de Sant' Anna, were traversed. 



Geologic Features Treated. 



The geologic features in the north which principally attracted the 

 attention of the writer are the following: 



1. Structure in the basement series, as indicated by the strike and 



dip in the foliation planes of gneiss and schists. 



2. The Ceara Senes of ancient sedimentary rocks; its characteristics 



and distribution. 



3. Granite, in its relation to gneiss and schists. 



In the southern area the same features are of note, with the substi- 

 tution of the Minas Series of quartzites and schists for the Ceara 

 Series. 



Minor features, noted throughout the region, which seem to be of 

 some geologic importance, are: The widespread occurrence of partially 

 rounded quartz gravel; the uncommon occurrence of basic igneous 

 rocks, and the scarcity of springs. 



Structure. 



With the areal discussion of structure in the basement-series it is 

 convenient to combine the notes on structure in the Ceara Series, 

 for, so far as has been observed by the writer and by others, the struc- 

 ture in these ancient sedimentary beds is conformable with that of 

 the gneiss and schist. Indeed, in a number of places the schist may 

 be a member of the sedimentary series. The trends of granitic 

 masses and of pegmatite dikes have also been mentioned in the areal 

 treatment of the structure. 



From Campina Grande Weshvard. In the vicinity of Campina 

 Grande the gneiss is rather deeply disintegrated, but where well 

 exposed it shows uniform strike about N. 70° W., true. Numerous 

 small dikes of pegmatite traverse it in various directions, and. horn- 

 blende gneiss, which easily cleaves into slabs, is used for flagging. 

 The constant strike and steep dip continue northwestward throughout 

 nearly all the distance to Soledade. Pegmatite dikes become less 



