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THURSDAY, AUGUST 2, 1917. 



AMERICAN AND ANTARCTIC GEOLOGY. 



(i) Geology: Physical and Historical. By Prof. 

 H. F. Cleland. Pp. 718. (New York : American 

 Book Company.) Price 3.50 dollars. 



(2) British Antarctic Expedition, 1907-9. Under 

 the Command of Sir E. H. Shackleton, CV.O. 

 Reports on the Scientific Investigations. 

 Geology: Vol. ii., Contributions to the Palaeon- 

 tology and Petrology of South Victoria Land. 

 By W. N. Benson and others. Pp. vii + 27o + 

 plates 38. (London : W. Heinemann, 1916.) 

 Price 3 guineas net. 



<i) pROF. CLELAND 'S volume is an attempt 

 J- to provide a summary of physical and 

 historical geology which shall be both interesting 

 to read and serviceable as a students' text-book. 

 It has many excellent features; it includes a 

 well-selected collection of 587 illustrations and, 

 as the result of the author's wide reading, many 

 interesting facts which are new to general text- 

 books. Its most valuable contribution is in 

 the sections on vertebrate palaeontology, which 

 summarise the evolution of most orders of 

 mammals instead of referring only to a few. The 

 account of American stratigraphy and palaeogeo- 

 graphy should be useful to British readers, and 

 the convenient lists of folios of the United States 

 Geological Survey which illustrate various physio- 

 graphic forms should increase the 'educational use 

 of those most instructive maps. 



The main defect of the book is that the author, 

 perhaps owing to haste, has not always fully 

 digested the information collected, so that minor 

 errors and inconsistencies are numerous, and space 

 is sometimes devoted to obsolete theories of which 

 current views are also given. Among the mis- 

 takes of fact are that the Zambezi flows through 

 a deep gorge above the Falls ; that Australia has 

 no native grasses, and that its indigenous fauna 

 belongs to the earlv Tertiary ; that the sea-urchins 

 experienced little change in Palaeozoic times (com- 

 i pare Bothriocidaris and Melonites !) ; that Tham- 

 ', nastrea prolifera ranged throughout the Mesozoic ; 

 1 and that eskers are not- usually more than a mile 

 I long. In a future edition the author might alter 

 'the statement regarding Spirula (p. 531) and 

 abandon his inference from the steam-cloud of 

 Stromboli (p. 339). 



The student will pounce on many statements 



which he will be quicker to compare than to 



reconcile; thus, the Permian is sometimes a sub- 



Idivision of the Carboniferous, and at others an 



■"'^lependent system. Lava, on p. 298, is wiselv 



-tricted to rocks which "issue from the earth," 



^ et the intrusive sheet which forms the Palisades 



of the Hudson are called lava, and some mud vol- 



:anoes are attributed to the action of lava at 



ome depth below the surface. Hanging valleys 



are said to be proof 'of glacial action on p. 163. 



ilthough elsewhere in the book glaciers are said 



o have slight powers of erosion on smooth rock 



NO. 2492, VOL. QqI 



surfaces, and hanging valleys are described which 

 are due to non-glacial agencies. The author gives 

 two comparative diagrams of a group of ridges and 

 valleys, one with spurless walls and faceted ends, 

 the other with serrated crests; yet the former 

 is included as an illustration of stream erosion and 

 the latter as mainly due to ice action. The short 

 chapters on rocks and minerals are below the 

 standard of the rest of the book, and students are 

 unlikely to derive correct impressions from the 

 statements that hornblende has "slender flat 

 crystals," that syenite is granite without quartz, 

 and that diorite and gabbro consist respectively 

 o£ hornblende and pyroxene with "felspar of any 

 kind." 



The effort to simplify palaeontology is respon- 

 sible for the division of the Paleozoic corals into 

 the chain corals, cup corals, and honeycomb corals 

 — which are undefined popular terms that do not 

 form satisfactory classificatory subdivisions. 



The references to authorities indicate that the 

 work is based unduly on text-books and semi- 

 popular works rather than on original authorities. 

 Thus, in the accounts of the vertebrates, Hutchin- 

 son's " Extinct Monsters" is repeatedly referred to, 

 while in the summary of the evolution of the 

 elephants no direct reference is made to Dr. 

 Andrews, whose results are quoted second-hand. 

 Some pages are devoted to early man, but there 

 is no mention of Eoanthropus. 



Though Prof. Cleland 's text-book will be useful, 

 it is not up to the usual high standard of American 

 geological literature. 



(2) The second volume of the Geological 

 Reports on Sir Ernest Shackleton's Antarctic 

 Expedition of 1907-9 is a magnificent volume pre- 

 pared through funds raised in part by a lecture tour 

 by Prof, (now Major) Edgeworth David. He has 

 been unable, owing to his important services 

 on the Western front, to edit the volume, a work 

 undertaken by Sir Douglas Mawson. Prof. David 

 has contributed a preface, in which he explains 

 why he considers that the ice-barrier tongues from 

 the Antarctic glaciers are afloat and do not rest 

 on esker-like embankments built of their moraines 

 and subglacial gravels. 



The volume consists of a chapter on ice struc- 

 tures by Sir Douglas Mawson and of thirteen tech- 

 nical studies on the geological collections brought 

 back by the expedition. Sir Douglas Mawson 's 

 ice studies were made on the ice of the lakes, of the 

 sea, and of the stalactites in the ice caves; his 

 work shows how the ice structures vary with the 

 conditions which determine the elimination and 

 distribution of the brine, and they throw further 

 light on the conversion of neve into glacier ice. 

 Mr. Chapman contributes a series of reports on 

 the foraminifera and ostracods in mud from the 

 floor of the Ross Sea and from various raised 

 marine deposits on the adjacent coasts. Mr. 

 Hedley describes the moUusca from the same 

 marine beds, and remarks that their preservation 

 shows that "their geological age is of the 

 slightest." Mr. Chapman establishes some new 

 species, and reports the presence of some Arctic 

 species, especially Saccammina sphaerica, which 



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