246 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



luuulred metres at it^ northern end, where it joins the beach, to only a 

 few metres in its narrowest parts. At one point east of Jaragua there is 

 a big solitary mass of coral rock rising tliree metres above the general 

 level of the reef. Mr. F. Ambler of the Alagoas railway kindly made 

 photographs of this block from which the illustrations on pages 160 and 

 161 were made. The form shows that it has been undermined and one 

 end of the block has settled, lifting the other end into its present position. 



South of Maceio the reefs have not been examined. I was credibly 

 informed that the one at Rio de Sao Miguel was of sandstone, and that 

 south of that place the I'eefs are very fragmentary. It is also a remark- 

 able fact that there are no coral reefs (known) between the mouth of tlie 

 Rio Sao Francisco and the city of Bahia.^ 



The Bahia reef. — At Bahia there is a great coral reef off the east 

 shore of the island of Itaparica. This reef was studied by Mr. Rathbun 

 in 1875-76, and a paper on it was published by him in the "American 

 Naturalist." ^ Part of Mr. Rathbun's paper appeared in the Archivos of 

 the National Museum at Rio de Janeiro.' I did not therefore visit the 

 Itaparica reef, but have depended upon Mr. Rathbun's paper, which is full 

 and is given here at some length : — 



" The long island of Itaparica, often called the garden of Bahia, fills up 

 almost the entire southwestern quarter of the large Bay of Bahia, and contracts 

 its entrance to a width of about five miles. Its outer coast, running obliquely, 

 faces for the most part the open sea, and is at the mercy of its boisterous waves. 

 Skirting the central portion of this coast for a distance of nearly nine miles is 

 a slightly elevated coral reof, long since abandoned by true living corals and 

 given over to another class of workers, who are putting on the finishing touches 

 and coating it with a hard and durable substance. 



" This reef begins directly opposite the city of Bahia, in front of a little rocky 

 point named Jaburu, and stretches away southward, in the general trend of the 

 shore, enclosing behind it a narrow and shallow chainiel which, at the most, is 

 scarcely one-fourth of a mile in breadth, and generally less. It is most perfect 

 toward the northern end, and has, at irregular intervals, numerous breaks or 

 openings which admit the smaller boats that ply along the shore. Approach- 

 ing close to Penha, another rocky point about three miles from Jabun'i, it ends 

 abruptly ; but commencing again to the south, it runs onward to the Ponte da 

 Cruz, terminating for good on the rocky shore. The study of the geology of 



^ For a description of tlie Maceio reef see Prof. A. W. Greeley's paper, — 

 appendix to tliis paper, p. 2G8-274. 



^ Richard Rathbun Brazilian corals and coral reefs. American Naturalist. 

 September, IBT^^t. XIII , p. 539-55L 



* " O recife de coral do Mar Grande." Archivos do Musea Xacional, III., p 174- 

 183. Rio de Janeiro, 1878. 



