20 SOPER— GEOLOGY OF PARAHYBA 



PLATE in. 



A. Isolated serrote of granite in the midst of an area of schist and gneiss, 

 near Martins, Rio Grande do Norte. 



B. Exposure of sandstone along the Chapada do Apody, near Passagem 

 Funda, Rio Grande do Norte. 



PLATE IV. 



A. Serra do Porto Alegre, Rio Grande do Norte. The flat summit is of 

 sandstone which rests on crystalline rocks below. 



B. Part of the limestone scarp of the Chapada do Apody showing a luxu- 

 riant growth of vegetation. 



