AND RIO GRANDE DO NORTE, BRAZIL. 19 



ments consolidated, and the structure when it is rehable shows hori- 

 zontal bedding. I have not found any fossils in these beds but 

 Dr. J. C. Branner reports fossils from similar beds at Ponta de 

 Pedras which he refers to Tertiary age. It is not unhkely that 

 these beds (in Parahyba and Rio Grande do Norte), are of the 

 same age. 



24. The Serras of Porto Alegre and Martins are capped with 

 layers of quartzite, about 50 meters thick. Mr. Roderic Crandall 

 reports that the Serra Joao do Valle is a similar mountain. 



25. No fossils have been found in the sandstone of the above 

 named serras. 



26. The valley floor of the basin of the Rio do Peixe is com- 

 posed of a reddish sandstone, conglomeritic in places and inter- 

 bedded with a reddish clay. This area is from 9 to 12 kilometers 

 wide and is about 80 kilometers long. It is entirely surrounded 

 by cr}''stalline rocks. 



27. The age of this sandstone of the Rio do Peixe is provision- 

 ally referred to the Cretaceous, but so far as is now known no 

 fossils have been found in it. 



28. It will be noticed that practically the entire sedimentary belt 

 along the coast is tilted gently, toward the sea. 



29. There is a series of shifting sand dunes along the coast espe- 

 cially noticeable in the vicinity of Natal. 



30. There are many clay beds in the sediments along the coast. 

 Some of them may be of economic value. 



DESCRIPTION OF PLATES I.-IV. 

 PLATE I. 

 Geologic map of the states of Parahyba and Rio Grande do Norte, Brazil. 



PLATE II. 



A. Part of the Chapada do Sao Sebastiao, showing the topography and 

 the dense caatinga growth. 



B. Exposure of limestone near Passagem Funda, Rio Grande do Norte. 



