January 30, 1913] 



NATURE 



591 



back into prehistoric anthropology through the 

 brief period of two centuries, the earth itself, the 

 land that is still in process of exploitation, makes a 

 very natural appeal. The Geological Survey in such 

 countries takes the place of an Academy of Inscrip- 

 tions, and now the laboured memoirs of the 

 surveys are being condensed for students who are 

 to take their stand as citizens. South Africa, 

 Australia, and New Zealand, armed with such 

 accurate knowledge, will soon offer little field for 

 those spirited romanticists, the company promoters 

 of the mining world. 



(i) Prof. Schwarz, however, is himself romantic. 

 He stands among the prophets, and is apt to 

 perceive the sunburst where some of us still 

 remain doubtful of the dawn. .\ touch of adven- 

 ture is imparted to the present volume by his 

 unhesitating acceptance of the very attractive 

 planetesimal hypothesis, and of the far more 

 dubious conclusions of Brun in the volcanic field. 

 We are invited by him to a well-planned arena, 

 where nineteenth-century champions may be seen 

 rolling in the dust. Apart from this, he sets out 

 very justly to teach elementary geology in South 

 Africa by South African examples. His treat- 

 ment is so sound that we resent the introduction 

 of the European Zechstein and Kellaways series, 

 and so forth, in the table following p. 124, however 

 necessary these trifles may still be in examinations 

 conducted on traditional lines. 



The author starts in his preface with the fact 

 that brooks are unknown to his students, and by 

 p. 34 we have a description of boulder-streams 

 after torrential rains, on p. 35 we talk of vleys 

 and vloers, and on p. 64 we realise, from a 

 modern subtropical instance, the origin of our 

 own "crystalline sandstones." The African 

 climate permeates such chapters, and we must not 

 complain if the pumpkin-like roches moutonnees 

 on p. 43 and the treatment of glaciation on 

 pp. 40 to 44 appear to European minds defective. 

 There are some slips in the writing which suggest 

 haste, as when a bore-hole is stated (p. 54) to 

 be 6000 ft. thick, and when melilite-basalt (p. 63) 

 is described without mention of the mineral 

 melilite. 



In an account of heat-weathering, which is very 

 properly emphasised on p. 71, we are told that 

 the corners of a block expose a larger surface to 

 the sun than the flat sides. The matter is 

 better expressed in Prof. Marshall's "Geology of 

 New Zealand " (p. 46). Prof. Schwarz concludes 

 with an account of the stratified series in the -South 

 African provinces and in Rhodesia, illustrated by 

 maps and drawings of fossils, and full of interest 

 for European as well as African readers. 



(2) Prof. Marshall's book, coming so soon after 

 KO. 22.^7, VOL. qo] 



Prof. Park's larger treatise, reminds us at once 

 of the stratigraphical controversies that still awai; 

 settlement in New Zealand. Dwellers in the 

 British Isles find it hard to comprehend the vast 

 series of rocks in other lands that may be devoid 

 of fossil evidence ; but it is equally hard to compre- 

 hend why an unconformity should be demanded as 

 a proof of the distinction between two successive 

 geological systems. This seems the main point 

 with those who, like Prof. Marshall, reject the 

 view that the Waipara series is Cretaceous, and 

 insist on giving us a Cainozoic group which 

 begins with Cretaceous types of life (p. 197). An 

 author who believes " that too much attention has 

 been paid in the past to the palEeontological 

 evidence " seems to mark out his systems on older 

 grounds than those put forward by William Smith. 



The book is very well illustrated by photo- 

 graphs, and, like that of Prof. Schwarz, intro- 

 duces students to geology by means of the features 

 of the home-country in which they live. Glaciers 

 and recent volcanoes are brought in as present 

 witnesses, and the geographer and geologist in 

 other lands will welcome this convenient and well- 

 printed volume. One does not demand a full 

 treatment of rocks or minerals in a book that has 

 another and a special aim ; but the chemical 

 formulae on pp. 12 to 20 require a good deal in 

 the way of correction and punctuation. 



(:;) Mr. Siissmilch's book, also in the same 

 convenient format, is issued by the Department of 

 Public Instruction of New South Wales. It pre- 

 supposes a knowledge of geological principles, 

 and brings together a large amount of matter that 

 is distributed through official reports. This treat- 

 ment allows of greater detail than can be intro- 

 duced into the volumes on South Africa and New 

 Zealand. We find pleasure, however, in comparing 

 the account of the Glossopteris flora (p. 91) or the 

 Palasozoic glacial beds (pp. 61 and 96) with the 

 remarks of Prof. Schwarz on similar occurrences 

 in South Africa; and there is no doubt that the 

 three books should stand near together in our 

 libraries. Through its design, that on New South 

 Wales is naturallv the most informing. 



G. A. J. C. 



OUR BOOKSHELF. 



The T-itienty-Seven Lines upon the Cubic Surface. 

 By Prof. A. Henderson. Pp. vi + ioo+13 

 plates. (Cambridge: University Press, 191 1.) 

 Price 4^. 6d. (Cambridge Tracts in Mathe- 

 matical Physics. No. 13.) 

 This volume is a record of an individual attempt 

 to construct numerical models of the cubic surface, 

 founded on the lines of the surface ; it is carried 

 through with great earnestness, and so far as 

 possible with the simplest materials ; its obvious 



