462 JENKINS— GEOLOGY OF THE [May 29. 



the purest clay is used for making pottery and bricks. Ornaments, 

 household utensils, such as vessels for holding water, are made at 

 Santo Antonio and at Barreiros. These vessels are red-brown in 

 color and rather easily broken. They appear to have been patterned 

 after Indian styles, which may be a result of the Indian blood in 

 some of the people of this region. 



Soils and Agriculture. 



The distribution of plants in this region is very striking ; they are 

 dependent upon both soils and climate. Thus the rubber tree and 

 other shrubs grow over the sandy plateau region. Farther into the 

 interior the region is arid, almost a desert. Here the soil is of de- 

 composed granites and other crystalline rocks, and cacti and desert 

 shrubs are the principal plants. 



Bordering the great valleys, in the old alluvial flats, the carnahiiba 

 palm is the prominent tree, although this region produces many other 

 plants more or less intergrown. Occasionally forests of trees as 

 high as twenty meters may be found in these old filled-in valleys, as 

 the forest between Monte Alegra and Desterro. 



The mangrove swamps are typical of the borders of the estuaries 

 and streams. Here deep black mud is deposited. This alluvium is 

 what makes the fertile soil. 



Along the beach one might suppose that there was no vegetation, 

 but on the shores of almost every little cove there is a grove of 

 cocoanut palms and a little fishing village. 



The valleys contain a great deal of sand, but are on the whole 

 fertile. The natives use the most primitive methods in farming. 

 There was not a single plow seen about Natal. The soil contains 

 enough sand to keep itself fairly loose and the plants are simply 

 stuck in the ground and left there. Bananas, sugar-cane, cotton, 

 corn, and various kinds of tropical fruits are raised. Occasionally 

 cofifee bushes are grown in the shade of other trees. Mandioca is 

 raised in great abundance. Its root is made into farinha, the prin- 

 cipal food of the common people. 



At Carnahubinha there is a cotton-seed oil factory. Also at this 

 place salt is concentrated from the sea water which flows up the 

 Jundiahy at high tide. 



