BRANNER: THE STONE REEFS OF BRAZIL. 67 
As elsewhere pointed out, I regard the clays found in the lower 
portions of these reef sections as evidence of the present beach line, 
and of the reef itself having been formed against or deposited upon an 
older beach that formerly lay further landward. The el 
are not beach deposits, but are the ой 
sands, 
ays themselves 
shore equivalents of beach 
That these stone reefs should have withstood the seas that bre 
and over them, especially during heavy southeast g 
remarkable things about them, and especially so when we remember 
that only the upper part of the reef is consolidated. It is worthy of 
note also that when the reef is broken up the breaking seems to be due 
largely to the attack upon its landward side rather than to the force of 
the waves that break upon it from the sea, 
ak upon 
ales, is one of the 
At one place the force of the stream discharged into the harbor, and 
against the landward face of the Pernambuco reef, probably aided by the 
nature of the water, has undermined the reef. This is a common feature 
of the stone reefs all along the Brazilian coast, and is due in part to the 
fact that only the upper part of the reef is thoroughly consolidated. 
In some places this kind of undermining has led to the breaking up of 
the reef, and the surface blocks now lie strewn upon the bottom or tipped 
about in confusion. 
The fact that the outer face of the reef is not attack 
ously by waves is due to the protection afforded by the great quantities 
of Serpulae, barnacles, seaweeds, and the like that coat its outer surf 
The beach reef at Piedade. — Following southward 
from the southern end of the Pernambuco reef at Bö 
sea one has on the land side a low ridge of s 
— the continuation of that at Böa Viagem — 
water marshes and Lake Curcurana. 
therefore very much the same as tho 
Pernambuco reef. 
ed more vigor- 
face. 
along the beach 
a Viagem by the 
and some four metres high 
and behind this the fresh- 
The topographic surroundings are 
ве about the southern end of the 
The first signs of a stone reef in this direction are at the Piedade 
church, less than a mile south of Boa Viagem. At this place there is a 
small beach reef about a hundred metres long. 
but not flinty, and is of the same 
Its surface is etched in holes a 
seaweeds. 
The seaward dip of these rocks is clearly shown, and the following 
angles were noted : 43^, 5°, 6°, 64° 
эй. e following dips of the beach 
sands alongside were noted : 4°, 41°, 5°, 
The rock is quite hard, 
yellowish color as the beach sands, 
nd overgrown with a thin coat of green 
