Peneplains and Related Land Forms

No. 3622, APRIL 1, 1939 NATURE 569

while they are attending classes ! The corridor floors Dr. Lowery again, "it is our desire that the College are covered with grey mottled rubber to render the shall become one great educational and recreational movement of students as silent as possible, and community centre where men and women may meet supplementary to the main staircases, passenger lifts in their leisure time for the purpose of engaging in have been installed. matters of common interest, thereby securing the It was John Ruskin who wrote, many years ago, fullest opportunity for self-expression". "The entire object of true education is to make The material building of this huge college has been people not merely do the right things but enjoy the very efficiently carried out by the general contractors, right things". Yet, the pioneers of technical educa• Messrs. F. R. Hipperson and Son, Ltd., of London, tion were mainly concerned with providing a training to the plans of Mr. J. Stuart, the architect, but an which was severely utilitarian. But, as Dr. H. even greater work will now be undertaken by the Lowery, the principal of the College, aptly points out, principal and his large staff in laying the foundations "A new problem . . . has arisen-it becomes of another edifice which will undoubtedly reveal necessary to provide training for leisure as well as itself in the trained mind, skilled craftsmanship, for vocation". Here then is a new function implying cultured recreation and, what is most important of heavy responsibilities for the modern college. It is all, trustworthiness and reliability of character. As essential to recognize and to cater for the proper use R. W. Dale once wrote : "The immediately possible of leisure, and here, in this magnificent new institution, is hardly worth living for. It is the ideal that kindles ample opportunities are afforded for developing the enthusiasm and gives inspiration and vigour to all true recreational and communal spirit. To quote human effort". F. G. W. B.

T is now nearly fifty years since W. M. Davis such rank because they are enclosed by highland I introduced the term 'peneplain' for the surface areas. of low relief which might be expected to mark the Most other contributors to the discussion expressed end-stages of a long period of sub-aerial erosion agreement with Dr. Dixey, and Mr. J. M. Edmonds under stable conditions. The term was received with described somewhat comparable conditions in the a certain suspicion and lack of cordiality among Anglo-Egyptian Sudan. Dr. K. C. Dunham, however, British workers and it has been used comparatively noted that the Rio Grande and the Gila River are little in their writings. Geographers and geomorpho• flanked by erosion surfaces, up to 80 miles long and logists will therefore note with interest that the 30 miles wide, produced by lateral corrasion. These Geological Society recently discussed some of the would apparently rank as local peneplains in Dixey's questions at issue. scheme, but he thought this constituted an extension In introducing the subject, Dr. F. Dixey's main of the term peneplain and one unlikely to prove contention was that the term 'peneplain' is properly acceptable to American workers. applicable to local areas which, though extensive, The discussion ranged widely over other cognate are far from being of continental dimensions. The matters and several points of view were represented. common presentation of a cycle of erosion as running Prof. 0. T. Jones deplored the lack of any agreed its course in a region of homogeneous rocks and definition of the features of a peneplain. He main• resulting ultimately in the base-levelling of a whole tained that, in one sense, the whole of England and land mass leads, in his view, to an unwarrantable most of Wales is a peneplain rising gently from sea• attempt to limit the application of the term pene• level to more than 2,000 ft., and truncating all plain. He directed attention to the "two-peneplain formations from the Pre-Cambrian to the Pliocene. topography" described by A. D. Coombe in Uganda, Despite the considerable relief of parts of this surface, and common indeed throughout Africa, and he such relief can scarcely amount to 10 per cent of the showed that such conditions must inevitably arise thickness of strata removed by erosion. He also where weak and resistant rock-masses are juxtaposed. emphasized the probable importance of wind erosion The lower surface opened out in weaker rocks, such, in producing extensive surfaces of low relief. for example, as infaulted strips of Karroo sediments, Other speakers were, by implication at least, may have the characteristics of a true peneplain, unwilling to accept so wide and general a connotation even though locally interrupted by residual masses for the term 'peneplain'. Dr. Hollingworth pointed and abutting elsewhere against steep slopes. Thus out that Davis's conception of a single peneplain in there arose veritable flights of peneplains as between the Appalachian region is now challenged by several the northern end of the Nyasa rift and the Luangwa alternative and mutually inconsistent interpretations, valley. Here the following erosion surfaces are dis• most of which agree, at least, in representing the tinguishable: a late Jurassic surface at about surface as complex and composite. Similarly, Mr. 7,000 ft., a late Cretaceous or Early Tertiary surface J. F. N. Green expressed the belief that many sur· at 5,000 ft., a Miocene surface at 4,000 ft., and a faces in the south of England which might be regarded late Tertiary surface developed at about 3,000 ft. as peneplains on general inspection have proved on friable Cretaceous rocks in local troughs. Further, susceptible of dissection into distinct terrace-like a sub-Cretaceous surface has been exhumed locally features, separated by bluffs. Mr. A. A. Miller and by erosion and stands at about 2,000 ft. This surface Dr. S. W. Wooldridge raised a further issue in and the late Tertiary surface rank as local peneplains pointing out that many of the 'high-level platforms' in Dr. Dixey's sense, thou.gh others have denied them of Britain, as well as most of the 'fossil' surfaces,

that is, exhumed planes of unconformity, have been benches by lateral corrasion which may fairly be finished, if not formed, by marine agency. In many grouped with Crickmay's 'panplains' and the such cases it is clear that the drainage pattern has American examples adduced by Dr. Dunham. not been inherited from a previous cycle, as must The discussion gave a clear indication, if such be inevitably be the case with a true peneplain. Thus, needed, that the findings of geomorphology in the closely spaced wind-gaps in the Old Red Sandstone field of erosion surfaces now challenge the close ridges of southern Ireland indicate a consequent attention of the stratigraphical geologist and the drainage initiated upon the surface which bevelled geophysicist. Erosion surfaces, some trimmed by the structures. Similarly, the transection of anticlinal marine erosion and others demonstrably of sub-aerial lines by rivers in southern England indicates that origin, have been proved to have a wide extension over wide areas the drainage originated upon the and to maintain essentially unwarped attitudes over emergent floor of a Pliocene sea. Nevertheless, the great distances. As such, they constitute an important whole of the region was not submerged ; in parts of record of the later geological history of the continents, the Chalk areas of Wessex and the central Wealden supplementing th!'l sometimes scanty evidence of area the reconstructed hill-top plane reveals the deposition. Further, their existence cannot be characteristics of a true peneplain and the drainage ignored by those who seek to understand the nature was adjusted accordingly. It seems, moreover, that and extent of isostatic adjustment in the lithosphere. the Thames in earlier stages of its history cut wide S. W. WooLDRIDGE.

Physics 1n the Textile Industries

ESEARCH physicists working in industry con• ment showing the swelling of a wool fibre with R tinue to increase in number, and the Institute increase of water content, using as a micrometer the of Physics, by holding conferences on industrial capacity of a condenser in a heterodyne circuit. physics, does much to bring them together to discuss Thursday morning's programme was completed by their mutual problems. But the conferences are open a lecture from Dr. Ezer Griffiths, of the National to all interested, and the physicist has opportunities Physical Laboratory, on "Industrial Humidity Con• of making contacts with those of other professions trol and Measurement". He illustrated with many whose problems are essentially physical. slides the requirements of humidifying plant and The third conference, held in Leeds during March 23- humidity controls, and described the various ways 25, was devoted to "Physics in the Textile Industries". of measuring relative humidity, indicating the mei;hod The textile industries have been built up by many most convenient to each industrial process where years of experimenting coupled with notable inven• this is important. tions, and it has behind it a wealth of knowledge The afternoon of March 23 was devoted to a visit which must be learnt by the physicist if his work is to the Department of Textile Industries in the to be of utmost advantage to the industry. Meetings University, followed by Dr. C. C. Paterson's presi• such as that held in Leeds are thus of great value dential address to the Institute of Physics. He chose in enabling the physicist to discuss problems not only as his subject "Colour and Colour Rendering". This with other physicists, but also with those conversant was a lecture of exceptionally beautiful and instructive with the industry. Simultaneously, the industrial demonstrations. Dr. Paterson pointed out the high technical man has an opportunity of learning possible efficiency attainable from discharge tube lamps, applications of physics and physical devices to his and contrasted their spectra and colour-rendering industry. This is particularly important for the older properties with daylight and other sources of illumina• textile industries, where few factories have physicists tion. The colour triangle and C.I.E. units were on their permanent staff, and advances which physics simply and elegantly explained, and there followed has to offer must be introduced and cared for by striking demonstrations of the difference between the technical men. matched white lights for colour rendering. He pointed The conference was held in the Physics Depart• out that the appraisement of colour matching value is a ment of the University of Leeds. It was formally pressing but unsolved problem. The lecture concluded opened by the Vice-Chancellor, Mr. B. Mouat Jones, with illustrations of the improvement in colour and was presided over by Prof. R. Whiddington. quality and efficiency attainable in discharge tube Following established practice of the Institute, the lamps by use of fluorescent materials. lectures and discussions were informal, and will not The lectures on March 24 were by Dr. M. C. all be published. Marsh, of the Cambridge Instrument Co., Ltd., who The formal opening was followed by an address chose "The Contribution of Physics to the Develop• by Prof. Whiddington on "The Physics of Humidity". ment of Industrial Process Control", and by Mr. D. He discussed with demonstrations the properties of Harrison, who spoke on "Automatic Regulators for the small but important amounts of water in the the Textile Industries". These lectures brought to atmosphere, and indicated why relative humidity is the notice of all the many instruments now available for the textile industries a much more convenient for industry, and features of their design gave an measure of the quantity of water vapour in the air impressive illustration of the potentialities of physical than the fundamental measure, vapour pressure. He knowledge when applied to industry. then described properties of substances dependent The final lecture of the meeting was on "Heat on water content, and illustrated experimentally the Effects in Fibres and other Systems". It was given large heat effects associated with change in water by Dr. C. G. Darwin, director of the National Physical content of textile fibres. He concluded with an experi- Laboratory. It was a delightful lecture on a difficult