branner: the stone reefs of brazil. 227 



3° 51' 27"; longitude 33° 48' 57'' west of Greenwich. "The reef ex- 

 tends about oue and one-fourth miles in latitude and nearly one and 

 three-fourths miles in longitude and is covered at liigh water with the 

 exception of Sand and Grass islands on the west and the scattered rocks 

 on the south and east sides. These objects are from ten to fifteen feet 

 above the reef, which is formed of coral, generally level, though with 

 many holes in it. . . . We found coral bottom at fifteen fathoms, six 

 miles east of the reef, but no bottom at thirty fathoms, two and one-half 

 miles north-northeast, nor at seventy fathoms four miles southwest of it. 

 The tide rises about five feet." (See page 82 of that work.) 



Certain points are marked on Lieutenant Lee's chart as black rocks 

 amid the coral reefs, suggesting that the reef may rest upon a base of 

 eruptive rocks. ^ Findlay ^ has the following : " The Rooas. This low 

 coral reef is perhaps the most formidable danger in the Atlantic, It is 

 the only one of its character in that ocean — a true atoll isolated from 

 all the suiTounding lands, so many of which are found in the Pacific." 



This author quotes as follows from a report of a visit by Commander 

 Parish made in 1856. He " obtained coral bottom in thirteen fathoms," 

 before the island Avas sighted, and again he " anchored in twenty 

 fathoms," before the island was sighted, and again he " anchored in 

 twenty fathoms, coral bottom, at about two and one-half miles from 

 the shore." 



In 1857, Captain J. H. Selwyn, R. N., resurveyed the Rocas and 

 wrote of it then : " It is a perfect coral island, circular, about two 

 miles in diameter, and has in its centre a shallow lake with an opening 

 to the sea. The greater part of the reef is under water. Tliere are two 

 sand banks, one on the southwest side, and the other on the northwest 

 side of the island. These are ten or twelve feet above water at all tides, 

 and are two hundred or three hundred yards long. The smaller has on 

 it some stunted vegetation and hazel trees." Reclus speaks of the Rocas 

 as a " veritable atoll of coral like those of the Indian Ocean, enclosing a 

 lagoon about ten kilometres in circumference." ^ 



There is also a valuable article upon the Rocas published anonymously 

 in the "Mercantile ^larine Magazine."* 



^ Dr. J. B. Regueira Costa, of Pernambuco, has kindly obtained for me speci- 

 mens of the black rocks of Rocas, but up to the time this report goes to press they 

 have not been received. 



- Findlay, Alexander George. A sailing directory for the Ethiopic or South 

 Atlantic Ocean. 9th ed. London, 1883, p. 227-231. 



^ E. Reclus. Nouvelle gc'ographie universelle. XIX Anu'rique du Sud, 

 p. 223. Paris. 1894. 



* Mercantile Marine Magazine, XIII., p 3;5-50 ; G5-80; 141-143. London, 1866. 



