ST. PAULS ROCKS. [chap, i 



this cuttle-fish, which, though concealed in a hole, thus often led 

 me to its discovery. Tliat it possesses the power of ejecting 

 water there is no doubt, and it appeared to me that it could cer- 

 tainly take good aim by directing the tube or siphon on the under 

 side of its body. From the difficulty which these animals have 

 in carrying their heads, they cannot crawl with ease when placed 

 on the ground. I observed that one which I kept in the cabin 

 was slightly piiosphorescent in the dark. 



St. Paul's Rocks. — In crossing the Atlantic we hove-to^ 

 during the morning of February 16th, close to the island of St. 

 Paul's. This cluster of rocks is situated in 0° 58' north latitude, 

 and 29° 15' w^st longitude. It is 540 miles distant from the 

 coast of America, and 350 from the island of Fernando Noronha. 

 The highest point is only fifty feet above the level of the sea, and 

 the entire circumference is under three-quarters of a mile. This 

 small point rises abruptly out of the depths of the ocean. Its 

 niineralogical constitution is not simple ; in some parts tlie rock 

 is of a cherty, in others of a felspathic nature, including thin 

 veins of serpentine. It is a remarkable fact, that all the many 

 small islands, lying far from any continent, in the Pacific, Indian, 

 and Atlantic Oceans, with the exception of tlie Seychelles and 

 this little point of rock, are, I believe, composed either of coral 

 or of erupted matter. The volcanic nature of these oceanic 

 islands is evidently an extension of that law, and the effect of 

 those same causes, whether chemical or mechanical, from wliich 

 it results that a vast majority of the volcanoes now in action 

 stand either near sea-coasts or as islands in the midst of the sea. 



Tlie rocks of St. Paul appear from a distance of a brilliantly 

 wliite colour. This is partly owing to the dung of a vast multi- 

 tude of seafowl, and partly to a coating of a hard glossy sub- 

 stance with a pearly lustre, which is intimately united to the sur- 

 face of the rocks. This, when examined with a lens, is found to 

 consist of numerous exceedingly thin layers, its total thickness 

 being about the tenth of an inch. It contains much animal 

 matter, and its origin, no doubt, is due to tlie action of the rain 

 or spray on the birds' dung. Below some small masses of guano 

 at Ascension, and on the Abrolhos Islets, I found certain stalac- 

 titic branching bodies formed apparently in the same manner as 



