128 Reviews — Dr. R. F. ScJuirJf — Origin of Life in America. 



chief mineral and litliological characters of the formations and to 

 their economic products, little heing said about their method of 

 origin, and less about their life-liistor}-. 



This book should be found of great service to farmers, builders, and 

 estate agents, and its value is considerably enhanced by the numerous 

 references to the more advanced and special literature on the various 

 subjects, and the excellent index. 



V. — The Distribution and Origin op Life in America. Bj' Robert 

 Francis Scharff, Ph.D., B.Sc. 8vo ; pp. viii, 497, with 

 20 figures [maps]. London: Constable & Co., Ltd., 1911. 



FOLLOWING on the delivery in London of the " Swiney Lectures 

 on Geology" five years s^go, Dr. Scharff published the now well- 

 known Ilistory of the European Fauna. The present volume contains 

 tlie substance of his second series of lectures on the " Geological 

 History of the American Fauna ", but the subject-matter has been 

 amplified and enlarged. It should be mentioned that owing to unusual 

 circumstances notice of this valuable book has been somewhat delayed. 



Each one of Dr. Scharff's fifteen chapters deals with a separate 

 region, e.g. Greenland, north-eastern North America. The wealth 

 of information contained in this book, which is furnished with twenty 

 helpful maps, is conveyed in an interesting fashion ; and reference 

 to the numerous authorities quoted throughout the book is made in 

 a fairl}' complete bibliography at the end. 



As might be expected, the problems connected with the Ice Age 

 form an important part of this book. There is ample biological 

 evidence now available to show that the formation of two land 

 bridges, connecting North America with Europe on the east, and 

 Asia on the west, closed in the Pacific and Atlantic Oceans on the 

 north about the same time. Hence the warmer climate in Pre- 

 Glacial times must be attributed to the fact that the Arctic Ocean 

 received more abundant warm currents then than now. The idea of 

 a former land-connexion joining Scotland, Iceland, Greenland, and 

 Labrador, put forward on several independent grounds, has its 

 strongest confirmation, Dr. Scharff thinks, in the geographical distri- 

 bution of Helix hortensis, a typically West European species. This 

 snail has been found in the mainland of Europe, Ireland, Shetland, 

 the Faroes, Iceland, South Greenland, Labrador, the islands off the 

 north-west coast of North America, and part of the opposite mainland ; 

 and it has lately been collected from the Pleistocene of Maine. That 

 geological evidence as to the date of this land-connexion will ever be 

 forthcoming seems far from probable. 



Among other instances of former laud-connexions adduced in 

 discussing the distribution of various animals are the mid-Atlantic, 

 the South Atlantic, and the North Pacific. The account of the fauna 

 of the Galapagos Islands is particularly interesting and important. 

 The author inclines to the view of Professor Baur that this archi- 

 pelago represents the remnants of a sunken land-mass once uniting 

 the West Indies, Cocos Island, and Central America, and is not, as 

 Darwin held, of volcanic origin. 



