BRANNER: THE STONE REEFS OF BRAZIL. 229 
sent by Mr, Sampaio from the vicinity of Cidade do Forte belong to the 
genus Nullipora.” 1 
At a number of places along the coast of Rio Grande do Norte the 
reefs are neither coral nor of the ordinary recent sandstone, but are of 
the more resisting iron cemented sandstones of the Cretaceous or Ter- 
tiary series. These beds, as has been pointed out in the geological intro- 
duction, are often formed at the bases of the bluffs, where, when the 
overlying beds are removed, they are in the right position to leave reefs 
close to mean tide level. Such are the reefs off the Pittinguí, Cape 
Branco, Jacumä, etc. Even if the Sio Roque reefs are all of coral, the 
chances are that they are built upon some such base as the one here 
mentioned. 
The absence of coral reefs along the entire coast from Natal, south 
latitude 5° 45, to the mouth of the Rio Parahyba do Norte, south lati- 
tude 6° 57, is striking. All the reefs within this space are either sand- 
Stone reefs or hard Cretaceous or Tertiary beds rising to about mean 
tide level. 
Fernando de Noronha. — The following notes upon the corals of the 
Fernando de Noronha archipelago were made during a three months’ 
visit to that island in 1876, when the writer was a member of the 
Geological Commission of Brazil. They are given here, not on account 
of their importance, but partly because mention bas been made by Mr. 
Н. N. Ridley of the “coral reefs ” about the group, and partly because 
one might naturally expect to find coral reefs about that group of 
islands. 
The main island of Fernando is volcanic, and all the outliers around 
it are of similar origin except Ilha do Meio and Ilha Raza, which are of 
aeolian sandstone. Properly speaking there are no coral reefs around 
Fernando, though growing upon the rocks about the group are a few 
Corals, and still other corals that were not found in place are from time 
to time torn up from the ocean bottom and thrown upon the beaches 
by the heavy surf. The following is a list of all the species collected 
on and about the island. For the identifications I am indebted to Mr. 
Richard Rathbun, formerly of the Geological Commission of Brazil, now 
of the Smithsonian Institution. 
| 1 J.B. von Spix u. С. Е. P. von Martius. Reise in Brasilien, IL, р. 799. München, 
828. 
* Journ. Linn. Soc. Zoology, 1890, XX., p. 559. 
3 J. C. Branner. The aeolian sandstones of Fernando de Noronha. Amer. 
Journ. Sci., 1890, XXXIX., p. 247-257. 
