April i6, 1908J 



NA TURE 



561 



THE GEOLOGY OF SOUTH VICTORIA 

 LAND.' 



THE National Antarctic Expedition is to be con- 

 gratulated upon the care and promptitude with 

 which its scientific collections are being worked out 

 by the staff of the .Natural History Museum. The 

 results are being issued with the fulness of illustra- 

 tion and the excellent form characteristic of the publi- 

 cations of that institution. The work has been 

 thoroughly supervised and edited. The first volume 

 has a general preface bv Sir Ray Lankester, and a 

 special preface by Mr. Fletcher, in whose department 

 the work of this volume was executed ; the biological 

 work is being edited by Mr. JefTrey Bell. The first 

 volume deals with the geological work of the expedi- 

 tion, and contains two reports. The first, by Mr. 

 H. T. Ferrar, records his observations upon the strati- 

 graphical and glacial geology. It is accompanied by 

 a valuable geological map of the district around 

 -MacMurdo Sound, based on the topographical survey 

 by Lieut. Mulock, and by an admirable scries 

 of photographs, that are a valuable supple- 

 ment to the text, but by whom they were: 

 taken is not stated. The geological specimens 

 obtained were mainly collected near the 

 Discovery's winter quarters, and on the oppo- 

 site part of the mainland. The extended field 

 observations and the large amount of material 

 collected are clearly the result of most inde- 

 fatigable and courageous work, under difti- 

 cult and dangerous conditions, and are a most 

 important addition to .Antarctic geology. The 

 geological formations at MacMurdo Bay are 

 divided by Mr. Ferrar into four series : the 

 recent volcanic rocks of the islands ; the 

 gneiss and granite that form the foot hills 

 and the basement of the mainland plateau ; 

 a wide series of horizontal sandstones, the 

 Beacon .Sandstones, that form the plateau of 

 southern Victoria Land; and some dolerite 

 sills intrusive into the Beacon Sandstones. 

 Infortunately there is no definite evidence as 

 to the age of these sandstones. Some plant 

 remains were found in them, and are de- 

 scribed by Mr. .\rber, according to whom 

 they are " unfortunately of little value 

 botanicallv " ; he calls them "carbonaceous 

 impressions," " which in all probability are 

 of vegetable origin." Mr. .Vrber concludes 

 that the specimens " neither permit of .iny 

 opinion as to the botanical nature or affini- 

 ties of the fossils themselves, nor of the geo- 

 logical age of the beds in which they occur.' 

 sidering the extent and abundant exposure of these 

 sandstones, the apparent rarity of organic remains in 

 them is significant. Mr. Ferrar devotes three chapters 

 to glacial observations, and describes Ross's ice barrier 

 as a Piedmont glacier, formed of confluent flow's of 

 land ice. The evidence offered in support of this con- 

 clusion is not very convincing, but until the issue of 

 the meteorological data collected by the expedition, it 

 is better to suspend judgment upon this question ; and 

 it may be hoped that Lieutenant .Shackleton's expedi- 

 tion will collect further information as to the intimate 

 structure of this ice. 



The second part of the volume is occupied bv Dr. 

 Prior's report on the rocks of South Victoria Land. 

 This report is masterly from its combination of refined 

 petrographic research with insight into the tectonic 

 bearings of the microscopic evidence. Dr. Prior shows 



1 National Antarctic Expedition, igoi-iQo4. Natural History, vol. i. 

 Geologv (Field-Geology: Petrography). Pp. xii+i6o; lo plates and 2 

 maps. (By order of the Trustees of the British Museum, 1907.) Price 30J. 



that the volcanic rocks include basalts, kenytes, 

 phonolites and trachytic phonolites; the dykes are of 

 camptonite, kersantite, and banakite ; and the base- 

 ment rocks of .South Victoria Land include granite, 

 diorite, gneiss and a crystalline limestone, of which 

 a specimen was found by Dr. \\'ilson. Dr. Prior's 

 report contains an interesting discussion of the 

 chemical relations of the rocks and their interpreta- 

 tion by the American quantitative system of classifi- 

 cation. He shows that the district is a distinct petro- 

 graphic province characterised by the association of 

 limburgites with intermediate rocks, which are rich 

 in alkali and contain anorthoclase as the predominant 

 felspar. He has calculated the percentage mineral 

 composition of the rocks and assigned to them the 

 naines they would receive in the .\merican quantitative 

 classification, and he concludes (p. 120) that "the 

 result shows that the classification supplies a variety 

 of naines to rocks not differing very widely in chemical 

 composition." 



The sequence of the volcanic rocks is a question of 



I.— The 

 depressed by 



ng upon the upper surface of 

 -level. National Antarctic Expedition 



Con- 



XO. 2007, VOL. 77] 



much interest, especially as some field observations 

 were regarded as showing that the trachytes were 

 younger than the basalts ; but Dr. Prior concludes 

 from his study of the rocks that this view is improb- 

 able, and that the trachytes and kenytes preceded the 

 basalts, as they did in the typical kenyte area in East 

 Africa. The most widely interesting part of Dr. 

 Prior's report is probably that discussing the geo- 

 graphical relations of .South Mctoria Land. He points 

 out that the rocks are chemically allied to those of the 

 .\tlantic coast type, and not to those of the Pacific 

 coast tvpe. He, of course, recognises that, according 

 to this use of the terms .Atlantic and Pacific, the 

 southern end of New Zealand must be regarded as of 

 the .Atlantic type, for the rocks of .South Victoria Land 

 are petrographically allied to those of Dunedin de- 

 scribed bv r)r. Marshall. .\n article in N.vit'RE (in 

 igoi, vol. Ixiii., p. 6io) on the probable geological 

 relations of Victoria Land pointed out that the sudden 

 change in the geographical grain of southern New 

 Zealand might very likely be continued into Ant- 



