





















92 THE CRUISE OF THE ABROLHOS. 
tide is coming in, and we must be in haste. We have yet 
time, however, for a short walk over the reef. 
The tide creeps over the reef. Our specimens are tram 
ferred to the deck of the launch, and we put out of our little = 
harbor, with a sigh that our exploration in the Abrolh 
waters are ended. 
The depth alongside the reef at low water varies ‘mod 
being in some places but three or four, in others ten feet or t 
more. Just alongside the reef, at least.on the inside wher Į 
ever I have examined it, the bottom consists of a soft, bluish, 
calcareous mud. The bottom usually slopes rapidly from 
the reef, and one may at a short distance away in sol 
places find a depth of seventy to eighty feet. Generally t 
reef is bordered by Chapeirões. 
Similar reefs are found a few miles farther south at Co 
Vermelha and the vicinity, but I know of none still farther 
southward. To the north they occur at intervals witht 
same characters at Itacolumis, Porto Seguro, Santa Cruz, 
Bahia, Maceió, and along the coast in the vicinity of Pi 
nambuco and northward. The Rocas, a very dangerous re 
lying in the latitude of Fernando de Noronha is a cool 
and is remarkable for its annular shape, inclosing a space 
the centre free from corals. 
From the descriptions of the sailors, Corda Vermelha is 
the mouth of the bay of Santa Cruz. I saw a few mang" 
trees growing upon it. A schooner had struck on the 
near by, and being carried over by the wayes, had 
close inside the reef. From the height to which the wa 
reached on the mast, I estimated the height of the reef 
thirty feet. 
Fortunately we had a pleasant trip home, and late in 
afternoon the launch was anchored off the melting-hous¢ 
the Barra. A few cornet notes brought out some 
inhabitants to welcome the incomprehensible Natu 
who, landing, spont the rest of daylight in orani 
