XXXII ANCIENT CORAL REEFS 497 



These masses, which varied from a few inches to two or three feet 

 in size, gave me the impression of having been torn off the bottom, 

 in some cases in recent times, in others perhaps centuries ago, by 

 the huge sea-waves that from time to time overwhelm this coast. 

 At Ancon, where they were sufficiently abundant to be used for 

 bordering the flower beds in the hotel garden, they were most 

 numerous in the vicinity of a rocky spur of andes'te that protruded 

 from the beach between the tide levels and was more or less 

 covered at high water. A few paces inland from the beach some of 

 these coral masses, evidently stranded long ago, were undergoing 

 that queer process of disintegration which everything calcareous 

 seems to undergo on the beaches and plains of this almost 

 rainless coast. Like the bones of the Incas lying b-eaching 

 on the neighbouring plains, like the sea-shells and bones of 

 bird and beast cast up long ago on the beach, they were falling 

 to powder where they lay, and the coral fragment lay often in 

 the midst of its own debris. The blocks on the beach proper 

 were for the most part still hard and compact, and the same 

 may be said of those observed on the beaches of Callao and 

 Arica. 



The corals were quite different from those with which I was 

 familiar in the reefs of the Pacific islands, and, bearing in mind 

 the known distribution of coral reefs, I was a little dubious about 

 them. Accordingly I sent some specimens to the British Museum, 

 and Mr. Jeffrey Bell has kindly informed me that they seem to be 

 decayed and much injured perforated examples of Porites. When 

 powdered they effervesce in an acid, but the bulk of the material 

 remains undissolved. 



No more eloquent testimony could be afforded of the rainless 

 climate than these corals crumbling on the Ancon plains when 

 washed a few paces inland from the beach. They could be 

 noticed in all stages of disintegration from the block surrounded 

 by a little line of disintegrated material, representing the initial 

 products of its own decay, to the crumbling mass, almost friable in 

 the fingers, that was lying in the midst of its own dust and loose 

 polyp-tubes, and finally to the little mound of debris that alone 

 remained. Mr. Darwin, in his Journal of Researches (chap, xvi.), 

 refers to a similar process of decay in the elevated shell-beds of 

 San Lorenzo, off the coast of Callao. On the higher terraces a 

 layer of saline powder, consisting of sulphates and muriates of 

 lime and soda but with very little carbonate of lime, was the sole 

 indication of the shell-beds. Dry climatic conditions at the sea- 

 VOL. II K K 



