226 



BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



IX. 



The Coral Reefs. 



PAOK 



Local details 226 



The Rocas 226 



Cape St. Roque reefs .... 228 



Lavandeira reefs 228 



Joao da Cunlia 228 



Ceara reefs 228 



Fernando de Noronha . . . 229 



Parahyba do Norte .... 2-32 



Between Parahyba and Recife 235 



Pernambuco to Santo Aleixo . 2o0 



Santo Aleixo 237 



Between Santo Aleixo and 



Maceio 239 



Analysis of reef rock . . . 241 



The Bahia reef 246 



Page 

 Between Itaparica and Cara- 



vellas 249 



OflE Caravellas 251 



Abrolhos reefs 256 



Thickness of the coral reefs of 



Brazil 259 



The age of the coral reef . . 261 

 Chemical composition of Bra- 

 zilian corals 268 



List of corals of the coast of 



Brazil 266 



Notes on corals collected. By 



A. W. Greeley .... 268 

 The Maceio coral reef . . . 270 

 Conclusions regarding the coral 



reefs 274 



When the work on the stone reefs was begun it was not intended to 

 include with it anything upon the coral reefs. It was only after the 

 work was nearing completion that it seemed advisable to utilize the notes 

 made on the corals, and to nse the geological history of the stone reefs 

 as far as possible to throw light upon that of the coral reefs. For this 

 reason these notes are fragmentary. I have endeavored, however, to 

 bring together what otliers have written upon the coral reefs in order to 

 make the paper as nearly a complete account of the coral reefs of Brazil 

 as can be written with our present information. 



The accotnpanying map sliows tlie distribution of the coral reefs so far 

 as it is known (Plate 1) at present. 



Local Details. 



TJie Rocas. — In 1852 tlie IJocas was visited and was first mapped 

 and described as a coral islaml.-^ Tliis island is eighty-four miles due 

 west of the Peak of Fernando de Xoronlia, and one hundred and forty- 

 four miles from the Brazilian mainland. Its centre is in .south latitude 



1 Report and charts of the cruise of the U. S. Brig "Dolphin " made under the 

 direction of the Navy Department, by Lieutenant S. P. Lee. U. S. Navy, Wash- 

 ington, 1854 (3.3d Cong., Ex. doc. 59, p. 81-85). 



