September 28, 191 1] 



NATURE 



439 



river valleys were excavated, or at least deepened, the 

 submergence of which had given rise to our magnificent 

 harbours. The discussion was continued by Profs. W. W. 

 Watts, E. Hull, and others, and Mr. Clement Reid, in 

 replying, pointed to the angles at which the tributary 

 streams entered the main valley as confirmatory of his 

 views. The slope of the ancient river-course from the Pur- 

 beck outcrops to the sea was almost that of the present 

 river. Pebbles of Purbeck chert were now in a different 

 drainage area from their source. 



The earlier hours of Monday were devoted by the geo- 

 logists to a joint discussion with Sections E and K on the 

 relation of the Glacial period to the plant population of the 

 British Isles, a report of which will be given by Section 

 K (Botany). At 12 o'clock Section C reassembled in its 

 own room, when papers were read by Mr. W. B. Wright 

 and Mr. A. R. Horwood. Mr. Wright, in describing the 

 Lower Carboniferous of the Bundoran district of South 

 Donegal, gave an account of recent investigations by 

 officers of the Geological Survey on the fossils of this 

 area. The Lower Limestone has a conglomeratic base 

 resting on the gneiss, the Lower Limestone Shale being 

 completely absent. The study of the brachiopods and 

 corals showed that the Carboniferous beds of this area 

 were throughout of Visean age, and leads to an interesting 

 stratigraphical result, for it establishes pakeontologically 

 for this area the transgression invoked by Jukes, on purely 

 lithological grounds, to account for the anomalies of the 

 Lower Carboniferous series in various parts of Ireland. 

 It shows, moreover, that this transgression reached the 

 Bundoran district about the end of Tournasian or the 

 beginning of Visean times. 



Mr. W. B. Wright also directed attention to the exist- 

 ence in a number of inland lakes in South Donegal and 

 the Wi stern Isles of Scotland of submerged pine-tree 

 stools in position of growth. They occur at a level several 

 feet beneath that of the outlet, which, being in many cases 

 over broken rock or boulder-clay, precludes any explana- 

 tion of a rise in the water-level due to peat growth. 

 These cases are unquestionably similar to some described 

 in Sweden, and are probably due to a drier climate, during 

 which the lakes rarely had any overflow. He pointed out, 

 however, that the mere presence of forests in the catch- 

 ment basin might, by checking drainage and promoting 

 transpiration, have in itself caused the partial drying of 

 the lakes. 



Mr. Horwood 's papers dealt with some new Rhoetic 

 fossils from Glen Parva, and with the shell-laver in 

 Mollusca. 



On Tuesday, September 2, Mr. R. W. Hooley read a 

 paper on the discovery of remains of Iguanodon manlelli 

 in the Wealden beds of the Isle of Wight, in which the 

 existence of two forms, a smaller and a larger, as in 

 Belgium, was revealed. These variations he attributed to 

 Sexual rather than to specific differences. He exhibited a 

 model in wood of the pelvic bones which showed a remark- 

 able balance, and the bones gave evidence that the animal 

 was fitted for bipedal progress, the pressure of the heavy 

 tail upon the pelvic bones enabling it easily to assume an 

 upright position. 



Prof. E. S. Moore, of the State College, Pennsylvania, 

 ftcribed beds on the border of the Appalachian system 

 which comprised a complex series of impure limestones 

 and sandstones forming a transition between the Cambrian 

 and Ordovician, which included calcareous and siliceous 

 oolites and beds of chert and limonite. The oolites form 

 thin and irtegular beds covering an area of more than 

 forty square miles. The calcareous variety probablv owes 

 its origin to a mixture of sand grains and calcium 

 :arbonate, and to the fact that there were frequent alterna- 

 tions from a condition of deposition of limestone to a 

 disintegration, solution, and redeposition of this rock. 

 The evidence for this conclusion is found in the fact that 

 the oolites occur in a complex mixture of calcareous sand- 

 stone and limestone, with alternations to thin beds of 

 limestone-conglomerate, and also that sand grains or frag- 

 Tients of sandstone usually form the nuclei of the concre- 

 tions. The siliceous oolites originated by replacement of 

 ■he calcareous concretions, because thev occur together, 

 ind the former grade into the latter. The source of the 

 silica is to be found in the chert nodules and in the sand 



grains occurring in the limestone. The chief solvents for 

 the silica are believed to have been organic acids and 

 meteoric water. 



following this paper Prof. Moore gave a lecture on the 

 pre-Cambrian beds of Ontario, illustrated by a fine series 

 of lantern-slides. The Rev. Dr. Irving described a fresh- 

 water limestone in the Lower Eocenes of the northern 

 flank of the Thames Basin, and a remarkable grey- 

 wether or sarsen stone, and Mr. T. Ross Thomson ex- 

 hibited lantern-slides to explain the various forms of the 

 Wealden ostracoda. 



Dr. W. F. Hume, of the Egyptian Survey, described 

 the first meteorite recorded in Egypt, and exhibited speci- 

 mens. It fell in the neighbourhood of the Alexandria- 

 Cairo Railway, about 44 kilometres E.S.E. of Alexandria, 

 and was seen by numerous natives. All accounts agreed 

 that the stones fell out of a clear sky from the north- 

 west, appearing as a white cloud variously estimated from 

 1 to 3 metres long. The meteorite exploded, breaking into 

 several fragments, the fall being accompanied by a 

 thunderclap. Numerous specimens were obtained from 

 localities lying in a north and south line, the extreme 

 points of which were separated about ij miles from each 

 other. They are all characterised by an intense black and 

 highly polished varnish of iron oxide, coating a green 

 granular rock resembling a dunite, and probably mainly 

 olivine. 



In addition to the older committees of research, new 

 committees were appointed to deal with excavations on 

 Creechbarrow Hill, Dorset, and in the Coralline Crag at 

 Sutton, at the base of which chipped flints had been 

 recorded. 



The instruction and pleasure of the geologists was 

 much enhanced by excursions to the Portsmouth Water- 

 works and the Isle of Wight. Saturday's full-day 

 excursion, under the able direction of Mr. G. W. Colenutt, 

 was very successful, and enabled the members to see the 

 lowest beds of the Wealden anticline at Brook Point and 

 the wonderful sections of vertically tilted Chalk and 

 Tertiaries at Alum Bay. 



AERONAUTICS AT THE BRITISH 

 ASSOCIATION. 



'Pi IE feeling produced by the discussion on the principles 

 of flight, which took place at Portsmouth on Sep- 

 tember 4 at a joint session of the Sections of Mathematical 

 and Physical Science, and Mechanical Science, of the 

 British Association, is one of disappointment. The ex- 

 pressed purpose of Mr. A. E. Berriman, who opened the 

 meeting, was to ask for the serious attention of matured 

 scientific minds to be directed to a variety of specific 

 problems that have suggested themselves to students of 

 aeronautics during the recent development of flying- 

 machines ; but the discussion following his thoughtful and 

 suggestive paper practically ignored the lines for debate that 

 he had indicated, and the net result was to produce a mass 

 of mainly irrelevant remarks. 



The subjects to which Mr. Berriman confined his 

 remarks were : — 



(1) A consideration of the efficiency of the aeroplane as 

 represented by the ratio of thrust to load, suggesting certain 

 basic formulae, and insisting on the relative importance of 

 skin-friction. 



(2) The necessity for evidence showing how the effective 

 i! gle of a plane and its effective dimensions might be 



measured. 



(3) The question of stability. 



In reference to these subjects, he said that an hypothesis 

 that aeroplanes were supported in flight by the inertia of 

 the air led to the necessity of finding plausible expressions 

 for mass acceleration. Two dimensions of the mass of air 

 deflected were plausiblv functions of the span and the chord 

 of the plane ; the third, which defined the depth of the 

 stratus engaged and was known as the " sweep," was 

 taken as the empirical function of the chord. Acceleration 

 was obviouslv a function of the angle of the plane, and it 

 was suggested that the angle should be measured by " the 

 angle of deflection " at the point of intersection of two 

 tangents drawn to the entering and trailing edges of the 

 plane. 



NO. 



;i87, V0L - 87] 



