136 



AMAZONIA AND LA PLATA. 



ance of being the work of man. Its mean breadth ranges from 100 to 200 feet, 

 and the flat top remains exposed at low water. The rock consists of a compact 

 sandstone, which probably represents a range of dunes deposited by the water, 

 consolidated by calcareous substances and gradually covered with an extremely 

 hard coating of various animal and vegetable organisms. It resists the action 

 of the waves, and the oldest pilots detect no change in its general outlines. 



Fernando ue î^oroxha. 

 The eastern extremity of the continent, indicated by the headland of S. Roque, 

 is continued for a great distance seawards by a submarine plateau about 56 miles 



Yia-, 48. — Fernando de Noeonha. 

 Scale 1 : 100,000. 



LesJumeaux^ 

 Portuguese â 



Rat / 



F/atform /. 



V'lfge o ^ Ys^ongeBa/ 



The Brothers 



nZes C/ochers 



Cfface///'ère 



les ^jftes 



aux Joncs 



/ aux frétâtes 





52° PS- . 



We<;t oF firponwirK 



32° 2:;' 



On the Maps the place names differ with the nationality of the surveyors. 

 _^^.^_^___^^_ 2 Miles. 



broad. Here is the edge of the continental pedestal, where the water rapidly 

 deepens from 30 or 40 to 1,500 and even 2,000 fathoms. The first land visible 

 in this direction is the annular enclosure of las Rocas, a true coralline atoll, 

 like those of the Indian Ocean, enclosing a lagoon about six miles in circum- 

 ference. 



About 110 miles farther east is seen the volcanic island of Fernando de IToronha 

 disposed south-west and north-east, and separated from the continent by depths of 

 1,500 fathoms. This land, which takes its name from the mariner who dis- 

 covered it in 1503, occupies a space of no more that six square miles ; but within 

 these narrow limits is seen the most varied scenery, creeks, and havens, hills and 



