EDITORIAL NOTES. xi 



Oceanic and other Islands visited by the Challenger Expedition necessarily 

 deals, for the most part, with lithological or mineralogical descriptions. 



The necessities of the voyage, bad weather, or the difficulties of the 

 exploration, prevented, in many cases, the Naturalists from passing more than 

 an hour or two on shore ; they were thus unable to give any detailed account 

 of stratigraphical relations, and the collections of hand specimens were 

 sometimes limited to those rocks situated near the coast. 



In some cases these collections can give but an imperfect idea of the 

 lithology of the Island ; still it has been considered desirable to give as full 

 a description as possible of the specimens from regions but rarely visited, all 

 the more so as a knowledge of the Petrology of most of these Islands has a 

 peculiar interest, from their situation in the great ocean basins at considerable 

 distances from continental land. 



On account of the small size of many of the Islands, the author has, by 

 combining the lithological descriptions with the local details furnished by the 

 Naturalists, been able to give a sufficiently correct idea of the geological 

 character of the Island under consideration. A knowledge of the principal 

 types of rocks at certain points, shows in all probability the nature of the 

 whole mass, when supported by observations on shore and the generally 

 received conclusions as to the nature of Oceanic Islands. 



In the case of each Island an abstract of the observations of the 

 Naturalists is given at the head of the descriptions. These have been taken 

 from the Narrative of the Cruise or from special papers and reports. 1 

 References are also given to other sources of information from the works of 

 various geologists and travellers. 



The Report consists of 180 pages, and is illustrated by 34 woodcuts, 

 representing facts of micrographic lithology, 7 charts, and several views of 

 the Islands extracted from the Narrative of the Cruise. 



In addition to the lithological descriptions here given, there will be 

 found a detailed Memoir by the same author on the Lithology of St. Paul's 

 Rocks, published as Appendix B to Volume II. of the Narrative of the Cruise. 



1 Narrative of the Cruise of II.M.S. Challenger, vol. i. ; J. Y. Buchanan, Preliminary Report on 

 Geological Work done on board H.M.S. Challenger, Proc. Roy. Soc, vol. xxiv. pp. 611-623 ; H. N. Moseley, 

 Notes by a Naturalist on the Challenger, London, 1879 ; C. Wyville Thomson, The Voyage of the 

 Challenger, The Atlantic, 2 vols., London, 1877. 



