June 6, 1907] 



NA TURE 



^n 



PROGRESS IN REGIONAL GEOLOGY. 

 A MONG recent publications in tlie Verhandlungen der 

 "^ k.h. geologischen Reichsanstalt for 1906, it is fair 

 to note that Prof. Homes and Dr. Franz Heritsch have 

 replied to Vice-director Vacek's onslaught, the tone of 

 which we regretted in a previous article. The strati- 

 graphy of the picturesque basin of Graz thus receives 

 further explanation (p. 305). Herr Gejza v. Bukowski 

 (ibid., pp. 337, 369, and 397) reports his work in the far 

 south of Dalmatia. Among other points, he notes that the 

 Eocene Flvsch changes its lithological character according 

 to that of the rocks on which it lies. Dr. E. Romer's 

 discussion of what he styles " fossil dunes " (ibid., 1907, 

 p. 48) has a wide interest for students of the great 

 European lowlands. The author urges that the post- 

 Glacial valleys, which are cut in the deposits left on the 

 withdrawal of the ice, have exercised a controlling action 

 on the formation and origin of the dunes. Evidences of 

 formerly prevailing east winds, and, later, of our present 

 westerly winds, are clear to him, as to previous observers; 

 but he connects the direction of the dunes with that of the 

 river-valleys, into which the winds blew at right angles 

 to the valley-sides. His studies in Galicia, round the 

 head-waters of the \'istula and the Bug, assure him that 

 the typical barchan, the dune with concave front and out- 

 stretched wings, is a phenomenon of deserts, and is con- 

 stantly in a state of change. The European dune, now 

 often surrounded with peat and itself grown over, is a 

 stable producf connected with a climate of steppes, not 

 deserts'. Dr. Rdmer (p. 53) observes how Neolithic settle- 

 ments were established in the shelter of the dunes, in- 

 dicating a wetter climate, following on that of the east 

 winds and the steppes. Then a return of the steppe-climate 

 led to the Tormation of sandbanks over the hearths and 

 dwelling-places ; and, finally, our present moister climate 

 has restored the boglands and promoted the growth of 

 trees, .'\nyone who has seen the winds in Poland laying 

 bare the roots on the outskirts of a clump of pines will 

 realise how easily the present balance may be disturbed, 

 and how a slight meteorological change may allow the 

 dunes again to grow. 



In a paper on the Gosau beds of the lower valley of the 

 Enns (ibid., 1907, p. 55), Herr G. Geyer incidentally refers 

 to the occurrence of red pisolitic bauxite in the base of the 

 Cretaceous strata, at the unconformable junction with 

 Triassic dolomite below. Two analyses are given, both 

 with 25 per cent, of ferric oxide and about 50 per cent, of 

 alumina. 



The Tenth Annual Report of the Geological Commission 

 (for 1905, published in 1906) reaches us from the Cape of 

 Good Hope. Through Prof. Schwarz's appointment to a 

 chair at Grahamstown, the staff of the survey has been 

 reduced to two ; but the director, Mr. .\. W. Rogers, feels 

 that the grant for travelling is not large enough for the 

 requirements of three oflicers in the field. .^ pleasant 

 reference is made to the geological tour of members of 

 the British Association, which Mr. Rogers organised with 

 such conspicuous energv and tact. The director contributes 

 an account of a survey of parts of Uitenhage and 

 Alexandria, with preliminarv lists of fossils from the 

 Cretaceous strata. Prof. Schwarz describes the coastal 

 plateau south of the Outeniqua and Long Kloof Moun- 

 tains, the latter rising to some 5000 feet, and the plateau 

 or large shelf lying at 700 feet, bounded by a bold cliff 

 towards the sea. Prof. Schwarz (p. 82) now regards this 

 shelf as a continental ledge cut by the sea, and subse- 

 quently elevated. Mr. du Toit gives, in a paper on the 

 Indwe coal area, a striking plan and section of a dolerite 

 sheet undulating among horizontal beds of sandstone over 

 about 2000 square miles of country. The part played by 

 these intrusive basic rocks in the structure of hill-masses 

 In South .Africa is well seen in his other sections. Mr. 

 Rogers revises some of Stow's conclusions in a paper on 

 Hay and Prieska, north of the Orange River. Mineral- 

 ogists will appreciate his description of crocidolite and 

 Us alteration-products (pp. 157-161). An ancient glacial 

 conglomerate is well displayed at the top of the Griqua 

 Town series in this area, while the Permian Dwyka 

 boulder-beds are also represented in places. As an example 

 of the work which a pioneer survey has to undertake, it 



NO. 1962 VOL. 76] 



may be mentioned that the structure of 4000 square miles 

 of country, in parts impassable through drought, had to 

 be realised in some three months. 



More familiar ground is dealt with by Prof. Schwarz 

 (p. 261) in the Ceres and Worcester area, which is known 

 to most dwellers in Cape Town on account of the fine 

 rock-scenery of the coast-ranges along the railway. We 

 wish that the Hex River Valley (pp. 277-9) and some of 

 the adjacent splendid examples of folded strata could have 

 been illustrated by photographs, instead of by the rough 

 sketches employed throughout this paper and the others 

 in the report. Certainly, sunlight and opportunity are not 

 lacking for geological photography in South Africa, and 

 Mr. Rogers's well-known " Geology of Cape Colonv " 

 shows how the structure of so bare and open a country 

 lends itself to the intervention of the camera. The report, 

 with its envelope of maps, is a record of unflagging 

 energy; and we have since received sheets 4 (1906) and 

 2 and 45 (1907) of the colour-printed geological map of 

 the Colony of the Cape of Good Hope, on the scale of 

 3-8 miles to the inch. The topography is, of course, 

 broadly set down, without representation of the surface- 

 relief ; but descriptions of the type of country are written 

 across each distinctive area on sheet 45, and probablv 

 this practice will be continued. Sheet 4 includes the Great 

 Berg River from Wellington to its alluvial area in St. 

 Helena Bay, and the Breede River and Hex River on the 

 east side of the watershed, where they cross the strike of 

 the coast ranges in ravines of sandstone that remind one 

 oddly of the limestone cluses among the Juras. The 

 synclinal infolds of the Devonian strata are well indicated 

 in the south-east of the map. 



In the Records of the Geological Survey of India, vol. 

 xxxiv., part iii. (1906), it is pleasant to notf a paper by 

 Mr. R. D. Oldham on explosion craters in the Lower 

 CJjiindwin district, Burma (p. 137). These crater-pits are 

 often occupied by lakes, since they have been e.xcavated 

 by explosive action to a lower level than that of the 

 permanent saturation of the country. They show no sign 

 of heat or of normal eruptions of ash, although they occur 

 in a region of volcanic action. In accepting Mr. Oldham's 

 explanation, we are reminded of the hydrothermal theory 

 of the South African diamond-pipes, and of the trifling 

 amount of contact-alteration on their margins. 



In the same part (p. 172), Mr. Vredenburg discusses the 

 " Tertiary system " in .Sind, with references to his previous 

 paper on the Foraminifera as zonal guides in this group 

 of strata. In the field, he finds that the group, previously 

 regarded as a continuous one, *' includes five totally in- 

 dependent series," the unconformities between them being 

 fortunately clear in Baluchistan. The basal series is 

 thrown back to the Senonian, the supposed passage-beds 

 into the Eocene disappear, and there are evidences of dis- 

 turbance at the top of the Eocene and in .Middle Miocene 

 and Pliocene times. In Sind, layers of laterite, formed on 

 low-lying continental surfaces (p. 179), represent the strati- 

 graphical breaks. The amended classification leads to a 

 re-examination of the Echinoidea described by Duncan and 

 Sladen in 1882-6, and Mr. Vredenburg is able to separate 

 faunas formerly, and somewhat naturally, confused. The 

 stratigraphical breaks become all the more emphasised by 

 this revision of the genera and species. The paper has 

 thus a considerable additional interest for students of fossil 

 Echinodermata. 



Going further east, Herr Georg Boehm adds consider- 

 ably to his previous exploration of Jurassic strata from 

 Celebes to New Guine.i (" Neues aus dem Indo- 

 .'Xustralischen Archipel," Neues Jahrbuch fiir Min., &c.. 

 Beilageband xxii., 1906, p. 3S5). In Buru, contempor- 

 aneous volcanic ashes are found containing ammonites and 

 belemnites (p. 399). The occurrence of European soecies 

 in the Far East is regarded as surprising, but is paralleled, 

 as the author points out, by facts in animal distribution 

 at the present day. .Irgonaula argo and Octopus vulgaris 

 are cited as examples. 



The Geological Survey of A'cti' Zealand forwards to us 

 Bulletin No. 2, a quarto on the " Geology of the Alexandra 

 Sheet, Central Otago Division," by Prof. James Park, of 

 the L'niversity of Otago. The region is a mountainous 

 one in the South Island, and is of importance in the pro- 

 duction of gold. The possibility of the alluvial gold having 



