256 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



run in the same direction at other times of the year, but not so 

 strongly.^ 



Coroa Vermelha, also called "Sebastiao Gomes," a small island off 

 Vi9osa, south latitude 18°, is a coral reef. The reef is quite flat, and is 

 entirely covered by water at high tide. The margins are said to have 

 steep, almost wall-like faces. '^ Some five or six years ago a Rio company 

 shipped the reef rock from Coroa Vermelha to Rio de Janeiro, where it 

 was burned for lime. 



The Ahrolhos reefs. — The Abrolhos reefs I have not visited. It was 

 not possible to make an extensive study of them, and a visit of a day 

 during my stay at Caravellas hardly seemed worth while. 



Reclus speaks of the coral reefs of the Abrolhos as the most remark- 

 able of this part of the coast ; but as coral reefs, in size and interest 

 they are hardly comparable with the Parcel das Paredes. He also says 

 the Abrolhos are " trois ilots granitiques," ^ which they certainly are not, 

 though there is a sheet of olivine gabbro diabase overlying the sedi- 

 mentary beds upon and about which the coral reefs grow. 



In order to make these notes as comprehensive as possible, I add here 

 what Hartt has written about the Abrolhos reefs.'* 



" The islands of the Abrolhos lie about midway between the cities of Rio and 

 Bahia, a little south of the parallel of Caravellas, and at a distance of about 

 forty miles from the mainland. The position of the lighthouse on the island 

 of Santa Barbara is, according to Mouchez, latitude 17° 57' 31" south, longi- 

 tude 40° 58' 58" west from Paris. These islands are situated apparently near 

 the middle of the submerged border of the continent, which here, over a very 

 large area, lies at a depth of less than one hundred feet. They are four in 

 number, with two little islets, and they are arranged in an irregular circle, 

 three of them close together. All are rocky and rather high, Santa Barbara, 

 the principal one, being 33.22 metres in height. The length of this island is 

 about three quarters of a mile. Its outline is irregular, and it is very narrow. 

 It is composed of beds of sandstone, shales, and trap, which dip approximately 

 north-northwest, at an angle of from ten to fifteen degrees. Owing to this 

 northward dip of the strata, the northern side of this island presents a steep 

 slope to the sea, while on all other sides it is precipitous. The i.^land is almost 

 divided in two in the middle, by a cove indenting it on the southern side. . . . 



1 For further details and determinations of corals collected on these reefs, see 

 Hartt's Geology and jjhysical geography of Brazil, p. 203-211. 



2 Capitito Teneiite Collatino Marques de Souza, Revistadolnstituto Geographico 

 da Bahia, 1895, II., p. 27-29. 



8 Nouvelle Geographie Universelle, XIX. Amerique du Sud, p. 268. Paris, 1894. 

 * Ch. F. Ilartt. Geology and physical geography of Brazil, p. 174-200. 

 Boston, 1870. 



