1 879.] Brazilian Corals and Coral Reefs. 551 



very fully described the various Brazilian reefs formed by chapei- 

 roes, and there is little new to add ; but we will take a hasty 

 glance at them in order to complete our sketch. The Abrolhos 

 islands lie some forty miles from the coast, near the middle of the 

 submerged continental plateau, in about latitude 18 south. Sur- 

 rounding them is a very extended area of constantly warm and 

 pure water, everywhere less than a hundred feet deep. Just to 

 the eastward of these islands is a region, nine or ten miles long 

 and about four broad, over which the pillar-shaped structures are 

 thickly scattered, forming the well-known Parcel dos Abrolhos. 

 The chapeiroes occur here of all heights and sizes, but never 

 reach the surface, or coalesce to form a continuous reef. 



To the north-west of the Abrolhos, and reaching much nearer 

 to the mainland, is the largest reef region of the Brazilian coast, 

 called the Parcel dos Paredes, or Shoal of the JFalls. It is irregu- 

 lar in outline, being about seventeen miles long from north to 

 south, by about nine miles broad in the widest place. Within 

 this area are extensive connected reefs, as well as multitudes of 

 scattered chapeiroes. The northern part of the Parcel forms one 

 immense reef, reaching slightly above the level of low tide and 

 formed by the growth of large coral patches and by the coales- 

 cing and filling in of chapeiroes. This latter feature in reef 

 building has been noticed only on the coast of Brazil. The edges 

 of the reef are very irregular, but the upper surface, laid bare at 

 low tide, is of quite uniform height, although marked by many 

 scattered shallow pools. Running along the margin of this level 

 portion, and separating it from that which is constantly submerged, 

 is a slightly raised border, a foot or less in height, formed by the 

 growth of nullipores, serpula tubes and barnacles. At low water 

 the waves beat against this hard rim, which thus helps to protect 

 the upper part of the reef from wear. The submerged border of 

 the reef dips gently for a certain distance, and then breaks down 

 abruptly to a depth of three to ten feet, meeting a bottom of soft, 

 bluish, calcareous mud which slopes rapidly away, soon attain- 

 ing a depth of seventy to eighty feet. Chapeiroes surround much 

 of this large reef, and extending off southward from it, form two 

 other reefs, the Recife de Leste and Recife da Pedra Grande, com- 

 prising the rest of the Parcel. 



Several other reef patches, resulting from the growth of cha- 

 peiroes, occur between the Abrolhos islands and the mainland, 

 and also farther north along the coast of Bahia. 



