330 Revietcs—Dr. C. W. Andrews on Chrintinas Island. 



IT. — A Monograph of Christmas Island (Indian Ocean) : 

 Physical Features and Geology. By C. W. Andrews. 

 With descriptions of the Fauna and Flora by numerous con- 

 tributors. 8vo ; pp. xiii, 337, 22 plates, 1 map, text illustrated. 

 (London : printed by order of the Trustees of the British 

 Museum, 1900.) 



THE present work is the first monograph issued by the Trustees 

 of the Natural History Branch of the British Museum dealing 

 with the fauna and flora, the geology and palaeontology, of a 

 single geographical unit of the globe, and owes its inception to the 

 advocacy of the Assistant-Secretary, Mr. Charles E. Fagan, F.E.G.S., 

 who has, we learn, greatly interested himself in its publication. 



The little island that forms the subject of this monograph lies 

 to the south of Java, 190 miles from its shores, and must not bo 

 confused with its namesake in the Pacific Ocean. 



This almost undisturbed little spot of land, 12 miles by 9, is 

 now being opened up for commercial purposes, and it seemed 

 desirable that before its primitive fauna and flora were ousted by 

 man, a careful record of them should be made, whilst at the same 

 time it appeared likel}^ that its geological investigation would throw 

 light on the origin of coral islands, of which it was manifestly 

 one. Accoi"dingly, Sir John Murray having agi'eed to provide the 

 requisite funds, the Trustees of the British Museum granted the 

 necessary leave of absence to Dr. C. W. Andrews, whose selection 

 for the purpose of carrying out the investigation is seen by the 

 present volume to have been most amply justified.^ 



With the zoological and botanical results of the expedition, 

 interesting and important though they be, we have nothing to do 

 in these pages. The facts ascertained concerning the geological 

 structure of the island show that it presents some important 

 peculiarities, differentiating it from other oceanic islands, and 

 difficult to explain. It is, in fact, the flat summit of a submarine 

 mountain, whose steep slopes sink rapidly to a depth of over 

 14,000 feet below the sea. The summit of this mountain peak is 

 formed of a succession of tertiary limestones ranging in age from 

 the Eocene (or Oligocene) up to recent reef-deposits, with inter- 

 calations in the older beds of volcanic rocks. 



The tertiary beds, especially the Miocene orbitoidal limestones, 

 end abruptly on the coast in vertical cliffs, sometimes 250 feet high : 

 they must therefore at one time have covered a far wider area, and 

 have been reduced by peripheral faulting. 



The principal volcanic rocks are the basalts and basic tuffs at the 

 base ot the Miocene limestone, separating it from the Eocene (or 

 Oligocene) beds below, and the basalts and trachytes underlying the 

 latter. These older eruptive rocks form the basis of the island, 

 which basis Dr. Andrews considers "is almost certainly a volcanic 



^ We published some Notes of an expedition to Christmas Island by CW. Andrews 

 (reprinted from the author's paper read before the Eoyal Geographical Society,. 

 November 28, 1898) in the Geological Magazine, Dec. IV", Vol. VI (1899), 

 pp. 19-27. 



