88 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
three hundred metres long. Beyond this, however, there are several 
isolated patches lying in the direct axis of this portion and stretching 
halfway across the embayment or curve in the coast line north of 
Tamandaré. This bit of reef, together with the isolated fragments at 
its southern end, is in a line with the stone reef of Rio Formoso. Just 
behind or landward of this small reef, and about a hundred metres from 
it, there is still another sand reef lying along the beach. This on-shore 
reef is parallel with the outer one, but in composition it is softer, though 
of the same kind of material. It has a gentle dip seaward. Its sea- 
ward face is broken off squarely wherever the open sea strikes it. 
There are also a few remains of hardened sand rock between the Rio 
Formoso reef and the high lands west of it, but these remains or bits 
are scattered, and without the linear arrangement that characterizes 
the stone reefs. One of these localities is at Gamella Point, where soft 
calcareous sandstone is uncovered by the encroachment of the sea. At 
the Guadalupe Point, where the sea is also encroaching, a soft calcareous 
rock is being uncovered at high tide-level, less than a metre below the 
surface of the sandy soil. 
The map herewith, and most of the observations embodied in the 
part relating to Rio Formoso, were made by the writer in 1876. On 
revisiting the place in 1899 considerable changes were noticed in the 
beaches. At Gamella Point the sea was found cutting the land so that 
a large Gamelleira tree, that in 1876 was well up on the beach, and 
beyond the reach of the sea-water, is now a dead stump a dozen metres 
to the seaward of the high tide mark. Guadalupe Point is being cut 
away on the east side and filled in on the west. The holder of the 
property at this place states that he has lost more than a thousand 
coco palms by the encroachment of the sea during the last seven years. 
This point was mapped again July 27, 1899, and the two outlines are 
shown, with their appropriate dates, on the accompanying map. 
The stone reefs of the Rio Sapucahy, Alagoas. — The Rio Sapucahy is 
a small river in the State of Alagóas entering the ocean about thirty 
kilometres (in a straight line) northeast of Maceio, and three kilo- 
metres northeast of the village of Paripueira. The country west of 
the mouth of the river is, like most of the northern coast of Alagóas, a 
plateau of Tertiary sediments cut across by the river, and a strip of 
low flat land, partly mangrove swamps and partly sand flats, intervening 
between the base of the hills and the ocean, 
The Sapucahy stone reef lies right across the mouth of that river, 
and the stream debouches right and left round both ends of it. It is 
