594 AZORES. Sept. 1836. 



then by a slight change in the set of ciirrents, the loose 

 matter removed, so that the hard nucleus alone was left. 

 Although the swell of the open ocean breaks heavily on the 

 outside of this narrow and insignificant line of reef, yet 

 there is no record of its decay. This durability is much the 

 most curious circumstance in its history. Its protection 

 appears due to a layer of calcareous matter, formed by the 

 successive growth of several kinds of organic bodies, chiefly 

 serpulee, balani, nulliporee, but no true corals. It is a 

 process strictly analogous to the formation of peat ; and like 

 that substance, its effects are to preserve from degradation 

 the matter on which it rests. In true coral reefs, when the 

 upper extremities of the living mass are killed by the rays 

 of the sun, they become enveloped and protected by a 

 nearly similar process. It is probable, that if a breakwater, 

 such as that at Plymouth, was built in these tropical seas, it 

 would be imperishable ; that is, as imperishable as any part 

 of the solid land, all of which must some day suffer decay 

 and renovation. 



On the 17th we took our final leave of the coast of South 

 America, and on the last day of the month anchored at 

 Porto Praya. We staid there only five days, and on the 5 th 

 of Septeinber steered for the Azores. On the 19th we 

 anchored off the town of Angra, the capital of Terceira. 



This island is moderately lofty, and has a rounded outline, 

 with detached conical hills evidently of volcanic origin. The 

 land is well cultivated, and is divided into a multitude of 

 rectangular fields by stone walls, extending from the water's 

 edge to high up on the central hiUs. There are few or no 

 trees, and the yellow stubble land at this time of the year 

 gave a burnt-up and unpleasant character to the scenery. 

 Small hamlets and single whitewashed houses are scattered 

 in all parts. In the evening a party went on shore : we 

 found the city a very clean and tidy little place, containing 

 about 10,000 inhabitants, which includes nearly the fourth 

 part of the total number on the island. There are no good 

 shops, and there is little appearance of actiAatv, excepting 



