BRANNER: THE STONE REEFS OF BRAZIL. 237 



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 tabes. 



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 

 so hard, and is more calcareous. These beach rocks have a seaward dip 

 tliat would, if continued, carry them beneath the coral reefs ; from this 

 it is inferred that the landward portions of tlie 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 

 Pontes, heads of which, with nther coral rocks, are gathered here for the 

 manufacture of lime. 



Santo AIei.1'0. — The island of Santo Aleixo, also known on the hydro- 

 graphic cliarts as iS'avigators' 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, thougii 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- 



