AND RIO GRANDE DO NORTE, BRAZIL. H 



same horizontal relation exists clear to Mossoro, for if the sandstone 

 dipped uniformly seaward, even at an angle of one degree, it must 

 in the 60 kilometers from Passagem Funda to Mossoro attain a con- 

 siderably greater depth than 30 meters. The limestone has a thick- 

 ness of between 30 to 50 meters. This estimate is based upon the 

 exposures along the Rio Apody and upon two wells drilled, one in 

 Mossoro above mentioned, and the other in Macau. The well in 

 Macau showed the limestone to be 44 meters thick. The age of 

 these limestones lies between the late Cretaceous and early Tertiary. 

 Air. Crandall" reports fossils from them (these fossils are in the 

 museum of the " Servigo Mineralogico " in Rio de Janeiro), and I 

 have found a few. 



Finally, overlying the limestones and extending on to the sea, is 

 the third division of the sedimentary rocks, a more recent deposit, 

 mostly sands and clays. The surface of this deposit is very sandy 

 but when drilled into it is seen to contain a great deal of clay. The 

 sand is calcareous in places. I have not seen any bedded rock be- 

 tween the limestone and the ocean but in some places there are 

 patches of hard, sandstone boulders, often of a conglomeritic nature. 

 The best exposures of these recent beds were seen during a trip 

 from Lagoa dos Mattos to Areia Branca. From this first named 

 place on to Mutomba, and again for two kilometers at the Morro 

 do Thibau, the sandstone is exposed in a bluff which varies in height 

 from 15 to 20 meters. This rock usually has a belt of conglomerate 

 at the base about 3 meters thick. Over this is a highly colored sand- 

 stone, rather hard and cemented with iron. Next there is a soft, 

 marly sand, whitish and usually from 2 to 3 meters thick and with- 

 out bedding planes. Over all are dunes of medium-grained, reddish- 

 brown, unconsolidated sand. The whole bluff is highly colored and 

 may show shades of brown, red, purple, lemon color and white. 

 These beds nearly all contain more or less iron and lime and in some 

 localities contain a great deal of earthy matter including kaolin 

 and clay. 



Further down the coast just south of the village of Touros, 



6 Roderic Crandall, " Geographia, geologia, supprimento d'agna, trans- 

 portes e agudagem," Publication of the Ministerio da Viacao e Obras Pub- 

 licas, p. 31. Rio de Janeiro, 1910. 



