442 J. C. Branner — Peak of Fernando de Noronha. 



Art. XLIII. — Is the PeaJc of Fernando de Noronha a vol- 

 canic j^l^^g like that of Mont Pele f by John C. Branner. 



It is doubtful whether the writer would have ventured the 

 suggestion made by the title of this note if the idea had not 

 occurred many years ago to no less a person than Charles 

 Darwin. In his ''Journal," new edition, New York, 1878, p. 

 11, Mr. Darwin says of the island of Fernando de Noronha : 

 " The most remarkable feature is a conical hill about one 

 thousand feet high, the upper part of which is exceedingly 

 steep, and on one side overhangs its base. The rock is phono- 

 lite, and is divided into irregular columns. On viewing one 

 of these isolated masses at first one is inclined to believe that 

 it has l)een suddenly pushed %tp in a, semifluid state. At St. 

 Helena, however, I ascertained that some pinnacles, of a nearly 

 similar figure and construction, had been formed by the injec- 

 tion of melted rock into yielding strata, which thus had 

 formed the moulds for these gigantic obelisks." 



The italics (not Mr. Darwin's) direct attention to the chief 

 point of interest in the present connection. In his " Geolog- 

 ical Observations," second edition, page 27, Darwin again 

 refers to the Fernando peak, as follows : " At St. Helena there 

 are similar great, conical, protuberant masses of phonolitCj 

 nearly 1,000 feet in heiglit, which have been formed by the 

 injection of fiuid feldspathic lava into yielding strata. If this 

 hill has had, as is pi'obable, a similar origin, denudation has 

 been here effected on an enormous scale." 



The writer spent some months on the island of Fernando 

 many years ago while a member of the Geological Survey of 

 Brazil, and an article on its geology was published in this 

 Journal in February, 1889. The following is quoted from that 

 paper (vol. cxxxvii, page 152) : " The Peak is the most strik- 

 ing landmark in the South Atlantic Ocean ; it is 1000 feet 

 high, with the upper portion perpendicular or overhanging in 

 such a manner as to make the summit quite inaccessible. The 

 few drawings of this peak that have been published are taken 

 from the sanie point — the anchorage — and even the best of 

 them, that in the Challenger reports, conveys but a poor idea 

 of its grandeur. Seen from other points it presents a striking 

 variety of outlines." Two cuts of the peak are given in that 

 article, one of which was reproduced by Professor Dana in his 

 Manual of Geology, 4th ed., p. 263. Owing to the points of 

 view, neither of these cuts, however, gives a just idea of the 

 shape of the peak. The one in Dana's Geology was made 

 from a photograph taken with the camera pointing up at an 

 angle of forty-five degrees. 



