HASEMAN, GEOGRAPHICAL DISTRIB VTION IN SOUTH AMERICA 25 



Soundings as well as fossils indicate that the Brazilian coast at one 

 time extended slightly farther east than at present. There appears 

 to be little or no doubt that the Abrolhos and Barbados islands were 

 originally connected with South America ( ? late Mesozoic). To the east 

 of these islands, no shallow sea or numerous small islands exist, as they 

 do in regions like the West Indies, East Indies and Alaska, where we 

 know that elevations and subsidences have taken place. 



The abruptness of the present Brazilian coast is not necessarily evi- 

 dence in favor of a post-Paleozoic faulted coast. In fact, my own ob- 

 servations have convinced me to the contrary. The entire absence of 

 fossils along the coast of southeastern Brazil indicates a great stability 

 of this region. Inasmuch as in all this region nearly all of the rivers 

 flow west and southwest, away from the ocean, it appears that there is a 

 gentle dip towards the southwest. Of course much of the surface of 

 this region is covered by late and post-Paleozoic continental deposits 

 which have been deeply eroded. The erosion of these deposits as well 

 as the older rocks would produce an abrupt appearing coast just as is 

 seen on the north and east sides of isolated mesas, or portions of the old 

 Piano Alto, which will be taken up in the following pages. Therefore, 

 I believe that the abruptness of the southeastern coast of Brazil is due to 

 its stability, as is shown by the absence of fossils, and to the southwest 

 dip of continental deposits, especially of late and post-Paleozoic age 

 which have been deeply eroded, and not to a post-Paleozoic faulting and 

 sinking of a land-mass into abysmal depths, for which no positive geo- 

 logical evidence exists. Much of the abruptness, however, is nothing 

 more than sea cliffs. 



During Cretaceous times, there was a slight elevation of the coast of 

 central and northern Brazil. In comparatively recent times, the entire 

 Brazilian coast has risen 40 feet. 11 This is sufficient to change the 

 earlier coast line and to produce another line which is abrupt, but due 

 to ages of erosion and not to faulting. Moreover, there are analogies 

 for this abrupt coastal condition in which no extensive sinking of a land- 

 mass has occurred. 



Therefore, summing up all the geological evidence, the lack of east 



11 Hart, Krone and others have stated that the Brazilian coast has been elevated about 

 40 feet since the Pleistocene or Quaternary. I had ample opportunity to confirm this 

 view while traveling in Rio Ribeiro de Iguape and along the coast at various other 

 points of southeastern Brazil. The location and nature of the sambaquis (shell mounds), 

 the ocean caverns and wave marks along the bases of inland morros (hills) show that 

 the sea extended inland almost to the mouth of Rio Juquia (west of Iguape) even as late 

 as the time of the Indians in this region. In further evidence of this, marine shells are 

 dug up in wells east of Campos along the Rio Parahyba and along the west shore of 

 Lagoa Feia, which is now about eight miles from the seashore and about nine feet above 

 sea-level. 



