210 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



Mr. Hawkshaw was an assistant of Sir Jolm Hawkshaw, who had the 

 borings made through the stone reef at Pernambuco in 1874. His paper 

 gives the section disclosed by the boring upon the reef opposite the 

 marine arsenal. He I'aises the question whether the existence of a bed of 

 liard rock below the reef can be regarded as evidence of an older beach 

 consolidated when it was at the surface. He is of the opinion, however, 

 that the coast has recently risen. He says the cementing material is 

 carbonate of lime. He is of the opinion that these reefs have been 

 formed from long sand ridges with lagoons behind them; that "the 

 percolation of land-water charged with carbonic acid derived from the 

 decayed vegetable matter in these lagoons through the sand ridges will 

 account for the formation of the beach rock, the water taking up and 

 again depositing the carbonate of lime of the shells." " The flood-level 

 of the lagoon will determine the level of the upper surface of the beach 

 rock ; and that of the lower surface would be determined by the 

 cessation of the consolidating action at the level at which the sand Avas 

 saturated by sea-water." 



Henderson, James. A liistory of the [_sic'] Brazil ; comprising its geog- 

 raphy, commerce, etc. London, 1821, p. 382. 

 In speaking of Pernambuco, it is stated that "A recife, or chain of 

 reefs, which extends itself from the entrance of Bahia to Cape St. 

 Roque ... in no part appears so much like an operation of human 

 art as here. It is prolonged for the space of a league in a direct line 

 with and about two hundred yards from the beach, having the aspect of 

 a large flat wall, being always above the level of the sea, and at low 

 water six feet is discovei-ed." It is " perpendicular on the land side, and 

 gradually declining on the other.'^ 



Hinchcliff, Thomas W. South American sketches ; or a visit to Rio 

 de Janeiro '[sic'], the Organ Mountains, La Plata and the Parand. 

 London, 18G3. 

 On p. 11, he calls Recife "a coral reef, which extends, with few inter- 

 ruptions, like a regular sea-wall, for nearly four hundred miles along the 

 coast of Brazil." 



Keller, Franz. The Amazon and Madeira Rivers. New York, 1874. 

 This writer, in speaking of Pernambuco, says that : " On the remark- 

 able coral reef that protects the port are a fine new lightliouse and a 

 quaint old watch-tower. . . . This coral reef ... is extending all along 

 the coast of Brazil " (p. 26). 



