I9I3] REGION ABOUT NATAL, BRAZIL. 437 



one comes upon the border of a wide valley with unexpected groves 

 of carnahuba palms, fields of sugar-cane and bananas. A village 

 with its quaint church, set on the upland, looks out on the fertile 

 area while all the surrounding country is as dry and arid as a desert. 



The farther one goes into the interior the more arid the country 

 gets. The river valleys diminish rapidly in width, and low hills of 

 crystalline rocks are rounded almost to flatness by age and decompo- 

 sition. The granites tend to stand out as huge rounded domes, 

 carved and grooved from weathering, while the gneisses and schists 

 form the general base-level plain. The whole region reminds one 

 of the deserts of Arizona with its dry, warm atmosphere, its cacti 

 and desert shrubs, and its lack of water. 



It is in a belt about ten or twenty kilometers wide along the 

 coast that the rains have their most decided effect. This region 

 is covered with numerous small fresh-water lakes. Some of them 

 are connected with the ocean and some are not. In times of great 

 rains they overflow and connect with each other. In times of 

 drought some of them dry up completely, as Logoa Secca near 

 Extremoz, a mere depression now which is said to have been full of 

 water forty years ago. Often the lakes seem to have no outlet nor 

 inlet, but if they are examined more closely they are found to be 

 fed by springs occurring along the border just between the im- 

 pervious clayey iron-sandstones beneath, and the loose wind-blown 

 sand-dunes above. This was especially noticed in the case of Logoa 

 Bom Fim, about thirty-eight kilometers south of Natal. Villages 

 are scattered along the borders of these lakes and each has its cocoa- 

 palm grove. The people are very poor and live on the little they 

 are able to raise and the fish which are caught in the lakes. Other 

 lakes are formed in the river valleys dammed in at the mouths by 

 sand bars on the seacoast. These regions are the most fertile of all. 

 Papary is a typical example of such a place. 



Areal Distribution of the Formations. 



The sketch map of the region about Natal, given at the end of 

 this paper, shows best the general distribution of the formations. 



