June I, 1876J 



NA TURE 



99 



were off Cape Mesurado, still in depths of 2,500 fathoms : 

 and on the 21st they had run as far along the Western 

 Coast of Africa as they intended, being then off Cape 

 Palmas, and the Challenger's course was shaped for St. 

 Paul's Rocks. These rocks lie about 1° north of the 

 equator, and in longitude 29° 15' W., being about mid- 

 way between the South American and African coasts. 

 Although rising to a height of some 50 to 60 feet above 

 the sea-level, yet they are mere rocks, not more than a 

 quarter of a mile long. The sea deepens quickly in the 

 vicinity of the rocks to depths of from 1,500 to 2,200 

 fathoms. The wash of the waves is such that even 

 sea-weeds cannot retain their positions on the rocks. 



Proceeding still in a south-west direction, the little 

 group of islands called Fernando Noronha was reached 

 on the 1st of September, and some days were spent 

 exploring it. The group consists of a principal island about 

 four miles long by three and a half broad, and several 



smaller ones ; it is situated in the Atlantic, in about lat. 

 3° 58' S., long. 32° 22' W., and about 200 miles from the 

 nearest point of the American coast. The islands appear 

 to be of volcanic origin ; the peak on the northern side 

 of the principal island rises to a height of 1,000 feet ; 

 it is a mass of bare rock, the summit of which is 

 quite inaccessible. The cliffs are chiefly composed of 

 columnar basalt. The sea-depth in the neighbourhood 

 is from 1,000 to 2,000 fathoms. Trees abound on the 

 higher parts of the island, and wondrous creepers cluster 

 together in the branches of the trees. A species of 

 Cereus was found by Mr. Mosely on the cliffs. Only one 

 grass {Oplismenus colonus) was found on the main island, 

 but although shady, moist places occur about St. Michael's 

 Mount, neither on this nor on the main island were any 

 ferns, mosses, or hepaticte found, and lichens were very 

 scarce. Among the principal cultivated fruits are bananas 

 and melons, the latter being very plentiful, and of a 



Fig. 8. — Blown-sand Rocks, Bermudas. 



peculiarly fine flavour. Sugar-cane, cassava, maize, sweet 

 potatoes, were grown in large quantities. The species of 

 land animals on the island are not numerous, but indi- 

 viduals of several of them are most abundant ; two spe- 

 cies of lizards are recorded from the islands, one being 

 peculiar to the group. 



On the 4th of September the Challenger was some 90 

 miles south of Cape St. Roque, in 2,275 fathoms, with 

 globigerina ooze. On the 8th she was off Parahyba, in 

 2,050 fathoms, with mud. On the 9th the sounding gave 

 a depth of only 500 fathoms off Cape San Agostinho. 

 The depth increased off Macayo (September 11) to 1,715 

 fathoms, diminishing off the mouth of the River San 

 Francisco to 1,200 fathoms, and as the coast at this spot 

 was approached to 7C0 fathoms. On the 14th the Chal- 

 lenger was at Bahia, and stopping there a short time she 

 proceeded for a section across the Atlantic from Bahia to 

 the Cape of Good Hope. Owing to unfavourable winds 



and other causes, the little Island of Trinidad, an island 

 whose vegetation was then totally unknown, had to be 

 passed by, and the ship's course was directed to the little- 

 known islands of Tristan d'Acunha, and on the i8th of 

 October she was anchored on the north side of the large 

 island which gives its name to the group. This island 

 rises in a range of almost perpendicular cliffs of black 

 volcanic rock, in appearance somewhat similar to that 

 exposed in section on the Grande Curral,in Madeira. At 

 their base are dt'bris slopes, and a narrow strip of low 

 shore-land, on a portion of which lies the settlement. 

 Unfortunately, before much even of these slopes could be 

 explored by the landing party, a sudden squall came on ; 

 the recall was hoisted from the ship, and they had to 

 leave after a visit of only six hours. Grasses, sedges, 

 mosses, and ferns were found growing on the cliffs, and 

 hepaticae so abounded as to cover the earth with quite a 

 green sheet ; occasional patches of Phylica arborea were 



