BRANNER: THE STONE REEFS OF BRAZIL. 239 
covered with the holes made by these animals. Hard as this igneous 
rock is they have succeeded in boring holes in some places to the depth 
of nearly five centimetres. This sea-urchin is Echinometra subangularis 
(Leske) Desme — the same species as that found upon the stone reefs at 
the city of Pernambuco. 
On the north side of the island, where the waves are not во violent, a 
calcareous reef is forming among the eruptive rocks. 
The coral reefs between Santo Aleixo and Maceio. There are several 
small reefs south of Santo Aleixo and north of Rio Formoso. Of these 
the largest are one lying off Gamella, and another a little to the north 
and to the landward of it. 
At Rio Formoso the sandstone reef lies across the mouth of the river, 
and corals grow over the seaward side of the sandstone. Nearest the 
stone reef the corals occur in irregular patches, but further out they 
form two well-defined reefs. The positions of these reefs are shown on 
the map of Rio Formoso, Figure 51, р. 83. 
The channel between the corals growing on the outer face of the stone 
reef and the coral reef to the seaward of this has it perpendicular sides 
covered with fine specimens of living corals. The genus Mussa is espe- 
cially abundant and fine. The bottom where not covered with fine mud 
has growing over it fine specimens of Millepores, which are popularly 
known hereabout as itapitángas. 
It was on this inner coral reef that many of the finest specimens 
belonging to the Commissáo Geologica do Brazil were collected by the 
writer in 1875. Upon the extinction of the Commissáo this collection 
was turned over to the Museu Nacional in Rio de Janeiro. The corals 
from these reefs have long been burned for lime, and the most accessible 
of the large heads have been removed by the lime-burners. 
The outer Rio Formoso reefs cross the sandy Manguinho Point south 
of the river and continue as parallel reefs halfway across the bay north 
of Tamandaré. 
Off the point north of Tamandaré (see p. 161 for chart) the coral reefs 
begin again as broad double reefs, and cross the mouth of Tamandaré 
Bay, leaving one considerable break at the bar, and continuing south of 
it as a single reef. This reef stands well out of water at low tide. 
Tamandaré would probably be an excellent place to study the reefs of 
this part of the coast. The town is large enough to offer facilities that 
cannot be found at all places, the bay is accessible to large vessels, and 
the extent of the reefs, their height, and their having channels between 
them would be advantages not to be found at many places on this coast. 
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