102 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Tertiary (1) pebbles embodied in it. The surface is partly-flat and 
partly etched and rounded. 
The Rio Maracahype enters the sea twenty-three kilometres south of 
the Cape Santo Agostinho lighthouse. Up this stream half a kilometre 
above its mouth sandstone like that of the stone reefs is exposed at low 
tide on the north side. It contains many fragments of calcareous Algae. 
South of the Rio da Cruz and between it and the Ponta do Sáo José 
there are many exposures of soft calcareous sandstone on the beach. It 
contains many coral fragments and broken calcareous Algae. 
On the beach south of Säo José point there is much of this partly 
hardened rock containing many shells.. 
Four hundred metres upstream from the mouth of the Rio Maragogy 
(8. lat. 9° 3’) on its south side, and about sixty metres from the base of 
the Tertiary (T) hills to the west, is a soft sandstone containing recent 
shells. 
Rio Salgado, the next small stream south of the Maragogy, has a 
small reef of soft sandstone across its mouth. It is a rather patchy one, 
however, and is from one hundred to one hundred and fifty metres out 
from the beach. Part of this reef lies on the point just north of and 
opposite Sáo Bento. These reef patches are here covered with Serpulae, 
` barnacles, and oysters. Similar rock is exposed within the mouth of the 
Rio Salgado. This looks as if it extended under the plain on which São 
Bento stands. It contains marine shells. 
One and a half kilometres south of the Barreira do Boqueiráo (8. lat. 
9º 9!) low tide exposes a sandstone reef. It bears N. 36° E. (magnetic) 
and dips gently seaward. The end examined on shore is only one of the 
fragments of this reef; other fragments lie in a line more than halfway 
across the embayment. 
Between Säo Miguel and Rio Camarigibe (8. lat. 9° 1 9’) at a place 
called Marceneiro the tides have undercut the bank and exposed soft 
calcareous sandstones from one to two metres thick. The rock is so pure 
that it is burned for lime. South of Marceneiro this bank of soft calca- 
reous sandstone continues to have a height of from one to 2.5 metres. 
At Riacho Doce and between that place and Garça Torta in the State 
of Alagóas are several fragments of stone reefs exposed on the beach. 
At one place there are blocks from three to eight metres long and a 
metre thick lying on top of a coral reef and granite boulders. At an- 
other place a sandstone reef sixty metres long rests on a coral reef, and 
at still another there is an exposure of one hundred metres of the sand 
reef alone. 
