PRESIDENTIAL ADDRESS. 649 



of geography might usefully spend, but I have had considerable experience of 

 working a department the income of which was not very far above the 

 minimum. Until now the Oxford School of Geography has been obliged to 

 content itself with three rooms and to make these suffice not merely for lecture- 

 rooms and laboratories, but also for housing its large and valuable collection of 

 maps and other materials. This collection is far beyond anything which any 

 other university in this country possesses, but it shrinks into insignificance beside 

 that of a rich and adequately supported Geographical Department like that 

 of the University of Berlin. This fortunate department has an income of about 

 6,000/. a year and an institute built specially for its requirements at a cost of over 

 150,000/., excluding the site. In Oxford we are most grateful to the generosity 

 of Mr. Bailey, of Johannesburg, which will enable the School of Geography 

 to add to its accommodation by renting for five years a private house, in which 

 there will temporarily be room for our students and for our collections, especially 

 those relating to the Geography of the Empire. But even then we can 

 never hope to do what we might if we had a building specially designed for 

 geographical teaching and research. Again, Lord Brassey and Mr. Douglas 

 Freshfield, a former President of this Section, have each generously offered 500/. 

 towards the endowment of a professorship if other support is forthcoming. All 

 this is matter for congratulation, but I need hardly point out that a professor with 

 only a precarious working income for his department is a person in a far from 

 enviable position. There is at present no permanent working income guaranteed 

 to any Geographical Department in the country, and so long as this is the case 

 the work of all these departments will be hampered and the training of a succes- 

 sion of competent men retarded. I do not think that I can conclude this brief 

 address better than by appealing to those princes of industry who have made 

 this great city of Sheffield what it is to provide for the Geographical Depart- 

 ment of the University on a scale which shall make it at once a model and a 

 stimulus to every other university in the country and to all benefactors of 

 universities. 



The following Papers were then read : — ■ 



1. The Origin of some of the more Characteristic Features of the Topography 

 of Northern Nigeria. By Dr. J. D. Falconer, M.A., F.R.G.S. 



The Protectorate of Northern Nigeria comprises an area of about 255,700 

 square miles, the greater part of which lies between Lake Chad and the con- 

 fluence of the Rivers Niger and Benue. The hydrographical centre of the Pro- 

 tectorate is the Bauchi plateau, which rises to a height of 4,000 to 5,000 feet above 

 sea-level. The rivers belong to two great hydrographical systems, the Niger- 

 Benue system and the Chad or desert system. The watersheds are lofty plains 

 characterised by a matured topography, while the more prominent ranges of hills 

 exert only a very secondary influence on the drainage system. The rivers in their 

 upper and middle courses flow over open plains whose surface is diversified by 

 numerous isolated granite domes, turtlebacks, and groups of rounded hills (insel- 

 berge). In their lower courses, on the other hand, they frequently flow in deep 

 and trench-like valleys, bounded on either side by ranges of flat-topped hills. 

 These plateau-like masses and tabular and conical hills have invariably been 

 carved out of horizontal sedimentary rocks, while the isolated domes and turtle- 

 backs of the upper plains afford clear evidence of a crystalline floor. 



The peculiar character of the river valleys is entirely due to the recent origin 

 of the whole river-system. It is believed that in late Tertiary times the surface 

 of the Protectorate was for the most part reduced to low relief, and that the 

 plains of Hausaland were continuous with the plains of Borgu and Ilorin across 

 the Niger valley. The crystalline plains with their domes and inselberge, as 

 well as the sedimentary plains with tneir flat-topped and conical hills, are to 

 be regarded as a final product of the subaerial denudation of a land surface 

 exposed to alternations of periods of erosion and periods of intense weathering of 

 the rocks in situ. Late Pliocene or early Pleistocene crustal movements brought 

 about the irregular elevation of this levelled surface into elongated arches and 

 troughs along axes which run approximately N.N.W. — S.S.E. and W.S.W.— 



