90 



bulletin: museum of comparative zoology. 



detached fragments lying beyond its southern end, and not shown on 

 the map herewith, which would give it a total length of something more 

 than a kilometre. 



A fact of unusual interest in regai'd to this bit of reef is that it over- 

 lies a dead coral reef. The overlap is plainly visible at many places 



Trrrm,^ 



Fig. 57. Section across the stone and coral reefs at Sapucahy. The vertical 

 shading on the right represents the coral reef. 



where re-entrant angles have notched the stone reef, or where large frag- 

 ments have been left isolated but fast to the coral reef. 



The coral reef visible here at low tide is from one hundred to two 

 hundred and seventy metres wide, measured from the outer margin to 

 where it is overlapped by the stone reef or by the beach sands. This 

 coral reef is almost perfectly flat and level. JSTot a single living coral 



■^ IBu.4^5^ 







4 



•^•- 



V ^^Cl 



^ Ocean 



Fig. 58. Sketch map of the southwest end of the stone reef at Paripueira, 

 State of Alagoas. 



could be found on its upper surface ; the coral most abundant in the 

 rock itself is Porites. 



Outside or seaward of this reef is still another coral reef with which 

 the inner one is not connected at the water's surface at least. 



