branner: the stone reefs of brazil. 



79 



tinues that far, must carry them beneath the coral reef that lies a few- 

 hundred metres oft" shore at this place. 



Tlie Cacimha and Serinhaem stone reefs. — The Rio Serinhaem enters 

 tlie ocean in south latitude 8° 36', just east of the island of Santo 

 Aleixo. The Cacimba and Serinhaem reefs lie across 

 the mouth of this river and in front of the flat lands 

 immediately north of it. 



The Cacimba reef is largely on the beach at the bot- 

 tom of the embayment between Ponta do Serramby and 

 Rio Serinhaem, while the Serinhaem reef lies across the 

 mouth of the river and extends well to the north, aff"ord- 

 ing partial protection to the embayment west of it. 



The country west of these reefs consists of a narrow 

 strip of sandy land next to the beach, with mangrove 

 swamps and sandy flat lands behind. These low flat 

 lands about the mouths of Rios Serinhaem and Trapiche 

 extend back to the foot of the Tertiary hills that rise 

 a few kilometres inland. 



At the town of Barra de Serinhaem, soft black Ter- 

 tiary sandstones are exposed at low tide along the river 

 bank for a distance of several hundred metres. 



The northern end of the Cacimba reef begins on the 

 beach south of Ponta do Serramby at a place called 

 Cacimba. A sand bank three metres high rises on the 

 land side of it, and two hundred metres west of the beach 

 a mangrove swamp follows southward parallel with the 

 shore. 



The northernmost four hundred metres of this reef 

 lies upon the beach ; then follows a break, beyond which 

 it touches the beach at only one point. It is a striking 

 and interesting fact that the southern end of this reef 

 curves gently eastward with the beach, keeping always 

 parallel with it and from forty to sixty metres away 

 from it. 



The south end of the Cacimba reef is more or less broken, until at last 

 it appears only as isolated patches, and finally drops in behind or laud- 

 ward of the Serinhaem reef, and comes to an end. 



About its northern end this reef stands fully two metres out of water 

 at low tide ; near its south end it is not quite so high. The surface is 

 much cracked, broken, and etched lengthwise, and there is a great 



