Proceedings Am. Philos. Soc. Vol. LV. No. 1 



Plate IV 



Serra do Porto Alegre, Rio Grande do Norte. The Flat Summit is 

 OF Sandstone which Rests on Crystalline Rocks Below. 



B. Part ok the Limestone Scarp of the Chapada do Apody Showing a Lux- 

 uriant Growth of Vegetation. 



