Bevieus — Bogcrs Sf Du Toit — Geology of Cape Colony. 561 



II. — An Intkoduction to the Geology of Cape Colony. By A. W. 

 EoGEEs, D.Sc, r.G.S., and A. L. Du Toit, B.A., F.G.S. ; with 



a chapter on the Fossil Eeptiles of the Karroo Formation, by 

 Professor R. Bkoom, M.D. Second Edition. 8vo ; pp. xiii, 491, 

 with geological map, 25 plates, and 29 text-illustrations. London : 

 Longmans, Green, & Co., 1909. Price 9s. net. 



WE welcome a second edition of this excellent handbook, the first 

 issue of which, by Dr. Rogers, was reviewed in the Geological 

 Magazine for 1905 (p. 135). Mr. Du Toit, of the Geological Survey 

 of Cape Colony, is now associated with Dr. Rogers in the authorship. 

 A new, clearly printed, and brightly coloured geological map has been 

 prepared of the Colony, with bordering tracts of Natal, Basutoland, 

 the Orange River Colony, and the Transvaal. Several new illustrations 

 are given, but the size of the volume has been increased only by 

 twenty-eight pages. The work has been carefully brought up to date, 

 and some details of minor importance in the first edition have been 

 reduced or omitted in order to keep the work within moderate limits. 

 Attention was previously called to the somewhat meagre index, and 

 in the new volume no references are given to any of the authorities 

 quoted, an omission which, from a bibliographical point of view, is to 

 be regretted. 



The oldest known formations grouped under the name Pre- Cape 

 rocks comprise " a heterogeneous collection of sediments and igneous 

 rocks both extrusive and intrusive ", all older than Devonian, but 

 otherwise of uncertain age. They include the Campbell Rand Series, 

 mainly blue dolomitic limestones, reckoned to be from 2000 to 

 3000 feet thick. Some of these beds are oolitic, some contain chert ; 

 there are also occasional altered sandstones or quartzites in the series, 

 as well as dolomitic limestones that have been changed into rocks 

 having the appearance and composition of quartzites. 



The Table Mountain Series, which forms the base of the Cape 

 System, is grouped with the Devonian, and appears to have been 

 formed under desert conditions with fluviatile and lacustrine deposits. 

 The succeeding Bokkeveld Series has yielded a fauna most nearly 

 related to that of the Devonian of South America, and having relation- 

 ship with the Middle Devonian of North America and with the 

 Lower Devonian of Europe. The still newer Witteberg Series has 

 yielded a number of plants, all the genera of which occur in the 

 Carboniferous of Europe. Quite recently, however, the first traces of 

 animal remains in the Witteberg Series have been recognized by 

 Dr. H.Woodward (Geol. Mag., November, 1909, p. 486), the remains 

 being portions of segments of Eurypterids, probably of the genus 

 Pterygotus. 



The Karroo System, with its basement Dwyka Series, includes 

 representatives of strata belonging to Permo-Carboniferous, Permian, 

 Triassic, and Jurassic ages. The term ' tillite ', suggested by 

 Professor Penck, is used for the Dwyka glacial conglomerate, which 

 is a hardened form of boulder-clay. It has yielded remains of 

 Gangamopteris. The shales above the tillite appear to be definitely 

 of Permian age. At a higher horizon in the Ecca Series remains of 



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