December 21, 1905] 



NA TURE 



187 



deVacineuse Lobo. " This operation costs t\d. per tree up- 

 rooted ; but the poles are thus a foot longer than those 

 that are simply felled, and the roots are used for fuel, 

 while the land can be at once planted, without waiting 

 three years from fear of the pine-weevil (Hylobius abietis), 

 which otherwise breeds in the stumps, and then destroys 

 the young crop planted to replace the felled trees. 



The last forest visited by the society was the Foret de 

 Soignes, one of the most magnificent beech forests in 

 Europe. The oldest crops consist of columnar beeches 

 130 years old, 130 to 140 feet high, averaging 45 feet in 

 girth at chest height, and containing per acre 7000 cubic 

 feet (quarter-girth measure). This forest of 10,210 acres 

 yields a net annual revenue of 18,000!. for timber alone ; 

 the game, chiefly roebuck, rabbits, and pheasants, is fully 

 worth 45. an acre, but is retained for the King. 



The geographical arboretum at Tervueren merits special 

 attention. Here, 75 acres of good undulating loamy land, 

 with a crop of small oak and other saplings, which serve 

 as a shelter-wood, are being planted with exotic trees. 

 The whole area is subdivided into the Old and New 

 Worlds, and each of these into smaller sections, represent- 

 ing countries running from north to south. Thus the 

 " New World " is first subdivided into the Pacific and 

 Atlantic regions, and the former into Alaska, Rocky 

 .Mountains, Pacific coast region, and Chile. The Atlantic 

 region into Canada and the Alleghany Mountains. The 

 Old World comprises Northern, Central, and Eastern 

 Europe, Siberia, Caucasus, the Himalayas, Japan, and 

 N. China. 



In each of these regions the characteristic trees, broad- 

 leaved and conifers, are planted in their natural mixture. 

 It is also intended to plant among them the shrubs and 

 herbaceous plants that naturally grow with the trees, and 

 this has already been done for Japan. Mr. Bommer, the 

 curator of the Botanic Museum at Brussels, is in charge 

 of this arboretum. He has an extensive forest nursery 

 where he rears the necessary plants. This bold and scien- 

 tific design is due to the initiative of the King of the 

 Belgians, who has presented the State with the splendid 

 domain of Trevueren, the management of which he still 

 controls. 



The Director-General of Forests, Mr. Dubois, has 

 certainly organised the administration of the Belgian 

 forests in a remarkably progressive way, and the system 

 he has adopted in Belgium is probably more suited than 

 those of France and Germany for the future development 

 of forestry in Britain. W. R. Fisher. 



THE CAPE GEOLOGICAL SURVEY. 1 



T 



HE presentation of the ninth annual report of the 

 Geological Commission of the Cape of Good Hope 

 will be welcomed by all interested in the prosperity of one 

 of our oldest colonies in Africa. We have been so long 

 accustomed to see similar surveys started and then 

 abandoned before sufficient information had been obtained 

 to yield permanent results that we were afraid that the 

 publication of this report might possibly have been post- 

 poned. The past record of surveys of Cape Colony has, 

 indeed, been a dismal one, so hampered have they been in 

 their prosecution, so undervalued have been the results. 

 Fortunately, necessity knows no law, and there are few 

 portions of Africa which do not possess a more or less 

 fully equipped geological survey. 



A considerable amount of new and useful knowledge was 

 obtained in Cape Colony during iqo4, though the results 

 an- not so complete as they doubtless would have been 

 if lack of funds had not prevented the continuation of the 

 survey in important areas, but where the cost of hired 

 transport was found to exceed the limit of the grant voted 

 for the survey. 



In the introduction by the director the main results 

 obtained during the past year are recorded, but all too 

 briefly. How little is known of the different rock groups 

 even in these southern and best known regions of Cape 



1 Minth Annual Report of the Geological Commission of the Cape of 

 Good Hope. Pp. 181. 1904. (Cape Town, 1905 ) 



NO. 1886, VOL. J$~\ 



Colony is shown by the discovery of a new set of rocks, 

 termed Nieuwervst series, which are found to be newer 

 than the Ibiquas and Malmesbury series, but older than 

 the Table Mountain Sandstone. The succession in southern 

 Cape Colony, the type region for South Africa, is thus 

 being brought into closer approximation with that of 

 northern Cape Colony and the Transvaal, with a result 

 that cannot fail to be beneficial to both. Further, a closer 

 parallelism is found to exist between the geological history 

 of South Africa and the southern continents than zoologists 

 and geologists dared to hope, but on which each alike 

 confidently felt would be the case. 



In the detailed account Mr. Rogers describes the geology 

 of the north-western part of Van Rhyns Dorp. Among 

 the Malmesbury beds - a characteristic feature consists of 

 the abundance of crystalline limestones intercalated 

 between slates and phyllites. The account of the intrusive 

 granites and the metamorphic rocks with the associated 

 sillimanite-cordierite schists contains much of interest. 

 The Ibiquas series and the unconformably overlying 

 Nieuwervst series deserve close attention, owing to the 

 light they will probably throw on the Transvaal succession. 



In the district of Long Kloof Mr. Schwarz finds the 

 geology to be highly complicated by folding. A somewhat 

 fanciful explanation is oflered to account for the elevation 

 of the mountains in this area being no greater than in 

 the less folded regions composed of the same rocks. 



In the description of the geology of Aliwal North, 

 Herschel, Barkly East, and part of Wodehouse, Mr. 

 du Toit enters into much detail concerning the stratigraphy 

 and composition of the Upper Karroo beds and the volcanic 

 phenomena associated with them. A great addition to our 

 knowledge of the sedimentary and volcanic beds of the 

 Stormberg series will here be found. By means of the 

 special reptilian contents in the upper portion of sand- 

 stones, red and purple shales, mudstones and clays, it 

 has been found possible to subdivide the great thickness 

 of the Beaufort series. For this superior group the term 

 Burgersdorp beds is proposed. Besides their abundant 

 reptilian contents, they are further interesting from the 

 occurrence of Lepidodendron in association with Glosso- 

 pteris and Thinnfeldia. 



In the succeeding Stormberg period chief interest i> 

 centred in the careful description of the volcanic outbur-t-., 

 more especially of that of the volcanic necks. Of these, 

 thirteen are recorded from Wodehouse, twenty from Barkly 

 East, and twenty-two from Herschel, those in Aliwal North 

 being left for further investigation. The description in- 

 cludes most reasonable hypotheses for the formation of 

 the different types of rock infilling the necks. The 

 immense flows of lava and numerous dolerite intrusions 

 receive due attention, the intrusion of the dolerites being 

 placed somewhere between the Middle Jurassic and Lower 

 Cretaceous. 



Questions of economic importance will be found to have 

 been thoughtfully considered. It is disappointing to find 

 that so far the coal seams met with in Aliwal North and 

 Herschel are thin and of less value than in the south. 



The introduction throughout the report of black and 

 white geological maps of the areas surveyed with a 

 sufficient number of place-names enables the reader to 

 follow the various descriptions with ease. The absence 

 of headlines, and the want of a copious table of contents, 

 constitutes a drawback to the general reader, particularly 

 where the report deals with petrological descriptions. 



Those persons who consider that the work of a national 

 survey should be primarily devoted to the economic aspect 

 of the inquiry will doubtless be disappointed at the 

 apparent poverty of the commercial results obtained by 

 the Survey since the date of its commencement in 1896. 

 The explanation is obvious. A national survey cannot be 

 formed for a particular section of the community interested 

 in the discovery of gold, coal, or diamond fields. It is, 

 however, expected of such a survey, and that of the Cape 

 fully realises the expectation, that the maps and memoirs 

 it publishes should represent the most trustworthy and 

 technical information it is possible to obtain as to the 

 geological structure of the country it professes to examine, 

 and on which the practical man who follows must and does 

 base his conclusions. W. Gibson. 



