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DRANNER: THE STONE REEFS OF BRAZIL. 291 
beach at that place. The patches of coral extend north of the trachyte 
exposures for 300 metres. These fragmentary reefs at Pedras Pretas 
are all dead so far as the corals are concerned, and are now covered with 
worm tubes, 
The next coral reef south of Pedras Pretas is at Cupe, ten kilometres 
south of Cape Santo Agostinho. It is only a short and broken one, is 
600 metres out from the beach with which it is parallel, and lies due 
east of the sand point at that village. 
At Porto de Gallinhas, south latitude 8° 28 30”, is another coral 
reef, about four kilometres long. On the beach opposite the reef are 
calcareous sands hardened into a soft sandstone. At one place — the 
large storehouse on the beach—this rock is hard and very like the 
fossiliferous rock of the stone reefs, but further down the coast it is not 
во hard, and is more calcareous. These beach rocks have a seaward dip 
that would, if continued, carry them beneath the coral reefs ; from this 
it is inferred that the landward portions of the coral reefs are newer than 
the sandstones. 
There is another coral reef just south of this one, at Maracahype. It 
lies across the mouth of Rio Maracahype, across Serramby point and 
passes on to the south, ending west of the Island of Santo Aleixo. Its 
total length is about nine kilometres. There are many small breaks in 
it within this distance. The most abundant species of the corals is 
Porites, heads of which, with other coral rocks, are gathered here for the 
manufacture of lime. 
Santo Aleixo. — The island of Santo Aleixo, also known оп the hydro- 
graphic charts as Navigators’ Island and Donally’s Island, is opposite 
the Barra de Serinhaem, and about two and a half kilometres from the 
Shore. The island is of eruptive origin and the rock composing it is a 
grayish-green quartz porphyry. It is 883 metres long, its greatest 
length being from north to south. On the southeast corner is a little 
hill 23 metres in height, and on the southwest corner is another smaller 
and lower hill. 
There is a quarry in the igneous rocks on the south side of the island, 
and east of the quarry are patches of a calcareous fringing reef, which 
is narrow near the quarry, but it widens to about 40 metres. From this 
point to the southeast extremity of the island the outer margin of this 
fringing reef makes nearly a straight line, though the land curves in to 
the distance of nearly three hundred metres, forming a sort of shallow 
bay. The reef ends at the southeastern point of the island. It is low, 
not rising more than a metre out of the water at low tide, and present- 
