422 



NATURE 



[August 31, 1882 



G — Mechanics 

 Brarawell, Sir F. J. — Relation between the Pressure at 

 different Points of a Structure on which Water and 



Air impinge ^25 



Whitworth, Sir Joseph — Screw Gauges 20 



Bramwell, Sir F.J. — Patent Legislation .. 5 



SECTION C 



GEOLOGY 



Opening Address by Robert Etheridge, F.R.S., F.G.S., 

 President of the Section. 



For sotce years it has been the rule or practice that the 

 Presidents should open the sectional meetings with an address, 

 selecting any subject which may seem to them best adapted to 

 the occasion. This custom I believe had its origin in this 

 Section, when the Association met at Aberdeen, and was due to 

 Sir C. Lyell, who was the first to deliver an opening address. 

 He selected for his theme the discoveries of M. Boucher de 

 Perthes, chiefly with relation to the occurrence and association of 

 flint weapons with the brnes of extinct animals in the gravels of 

 the valley of the Somme. 



The Geological Section, over which during ihe present meet- 

 ing I have the honour to preside, embraces a wide field of 

 research, and therefore allows selection from a large range of 

 subjects, so large indeed that it would be difficult to choose an 

 original one that would be acceptable and useful to those mem- 

 bers of the Association who may be present. It is thirty-six 

 years since the British Association last met in Southampton, and 

 probably not half-a-dozen members who attended the meeting of 

 1846 are now present, if living. We are, however, fortunate in 

 having with us to-day one or two who contributed tapers to this 

 Section thirty-six years ago. 



The Geological Section may be congratulated on its place of 

 meeting this year. Hampshire presents a wide range and field 

 of research to the practical, as well as the less advanced student 

 in geology. Truly may it be said that this area is classic ground. 

 No less than six distinct formations, with their subdivisions, occur 

 in the immediate neighbourhood and within reach of those mem- 

 bers who have honoured the Association with their presence this 

 year. Be it remembered that it is thirty-six years since the 

 British Association met in this city. Since then, or the year 

 1846, geology has indeed advanced with strides unsurpassed by 

 any other science. The Tertiary rocks of the Hampshire basin 

 alone have received from the hands of private and learned 

 physicists, as well as the long-continued labour of the Geological 

 Survey, the most careful and detailed research. It may well be 

 said that this rich field has not wanted competent labourers, 

 earliest and foremost of whom must be named Webster, Sedg- 

 wick, Prestwich, and Edward Forbes, who with Mr. Bristow 

 mapped out with so much care and accuracy the intricate struc- 

 ture of the Isle of Wight. To these must be added, through 

 later search, the names of Searles Wood, Wright, Fisher, 

 Tawney, Keeping, Judd, and others. Other portions of 

 Hampshire and Sussex bearing upon the question of the Anglo- 

 French Tertiary basin, have been elab irately treated upon by 

 Dixon, Godwin-Austen, Sir C. Lyell, and others. 



It may be a fitting preliminary to local communication which 

 will most probably come in, during the course of this meeting, 

 that I should summarise what has been done in this area. This 

 may be familiar to many, but there are others who may wish to 

 examine certain geological localities, the mention of which may 

 induce them to visit spots of much interest. It is scarcely the 

 duty of the president of this Section to devote the time allowed 

 to an opening address to the discussion of any original subject, 

 while work of unusual local interest has transpired during the 

 past year to justify him in drawing attention to a subject of much 

 importance connected with the stratigraphical position of certain 

 beds in the Eocene strata of the Isle of Wight ; a question of 

 local geologist interest, as well as bearing' upon the correlation of 

 the Tertiary rocks of Hampshire with those of France, Belgium, 

 and Germany. Instead, therefore, of offering to the Geological 

 Section an address on some special subject or branch of general 

 geology, I have deemed it more interesting, and certainly more 

 useful, to lay before you an outline of certain physical features 

 occurring within the immediate neighbourhood, and district in 

 which we are now assembled. 



I purpose therefore to call attention to the local geology of 



this area, especially as regards the Tertiary deposits of Hamp- 

 shire and Sussex, as forming or constituting the northern portion 

 of a vast series of deposits once continuous to Northern France, 

 the area now covered by the English Channel and the Solent, 

 and lying in the depression of Jurassic and cretaceous series. 

 The relation also of the Hampshire and Anglo-French basin 

 and its ternary fauna to that of the London or Anglo- Helgian 

 area will receive notice, as being part of the history of one great 

 period, the strata comprising the two areas being also once con- 

 tinuous, much of it being sub-equently removed or denuded 

 away from those areas now occupied by the English Channel and 

 German Ocean. 



Before especially noticing the Isle of Wight and the neigh- 

 bouring c asts, I must state that by laborious search over both 

 old and new ground, and through the very careful examination 

 of collected specimens during the past twenty years, great light 

 has been throw n on the geological structure of many local areas 

 hitherto obscure from want of critical palceontological knowledge 

 being brought to bear upon the fossil fauna or flora characteris- 

 ing the various marine and freshwater deposits with which the 

 surrounding district abounds. Greater precision has of late 

 been arrived at in the chronological arrangement of the cretaceous 

 and tertiary strata which occur both in the Isle of Wight and on 

 the mainland. 



Doubtle-s you are all aware that the strictest investigation as 

 to the distribution and organic contents of the Fluvio-marineTer- 

 tiaries of the Tie of Wight, was undertaken by Professor Edward 

 Forbes, when attached to the Geologi :al Survey from the years 

 1848-56, and subsequently Mr. II. W. bristow, F.R.S. com- 

 pleted all the older tertiaries and cretaceous rocks of the island, 

 thus producing a complete geological guide to this portion of the 

 Hampshire basin. The structure of the opposite coast to the 

 east, or that embracing Bracklesham Bay, Selsea, and Bognor, 

 was critically treated by Mr. Frederick Dixon in the year 1850, 

 (" The Geology and Fossils of the Tertiary and Cretaceous For- 

 mations of Sussex." By F. Dixon, 1850, 1st ed., 2nd ed 18.) 

 who was most ably assisted in his palceontological researches by 

 the most distinguished naturalists then living, each faunal group 

 receiving critical supervision and description. A second edition 

 of this valuable work appeared in 1S7S, wherein much new 

 geological and palaeontological matter is added ; both the Cre- 

 taceous and Tertiary reptiles were figured and de-cribed by 

 Professors Owen and Bell, the fishes by Sir Philip Egerton, the 

 Cretaceous echinodermata, by Professor Forbes. Mr. Sowerby 

 described the mollusca, and the large Crustacea were described 

 by Professor Bell, and the corals by Lonsdale. 



Selsea. 



I now draw your attention to a locality of extreme interest 

 both to the geologist and archaeologist, and where cause and 

 effect are manifested in both investigations, the historical portion 

 being based upon physical causes and changes that have long 

 been, and are still going on, to modify the form, extent, and 

 structure of the Sussex coast, from the mouth of Chichester 

 Harbour to Littlehampton and Bognor. In the year 1855 Mr. 

 Robert Godwin- Austen, F.R.S. and G.S., read before the Geolo- 

 gical Society an elaborate paper upon the " New er Tertiary 

 Deposits of the Sussex Coast," in which he also noticed some 

 peculiar features in the parts of the Isle of Wight and South 

 Hants bordering the Solent. 



From Beachy Head to Selsea Bill, the coast line lies east and 

 west, so that there intervenes a tract between the chalk range 

 and the sea which ultimately acquires a width of ten miles, as 

 from Lavant to Selsea. This tract is low and level, presenting 

 a series of superficial accumulations, remnants of a definite 

 Tertiary period, of w hich at no other place in England is there 

 any such record, and to which I ask your attention should any 

 journey to inspect the phenomena exposed along the shore of 

 Bracklesham Bay, or between Wittering and Pagham Harbour, 

 or Bognor be proposed. Espeoially may I refer to interesting 

 evidence as to local conditions during the glacial period. It may 

 not be known to many, or all present, that the peninsula of 

 Selsea is celebrated in English history as one of the places where 

 Christianity was first taught in this country. It was one of the 

 most ancient Saxon establishments. This peninsula was granted 

 by Edilwalch, King of the South Saxons, to Wilfred the exiled 

 Bishop of York, about the year 680. At that time it is stated 

 to have contained 5,220 acres of land, with 85 families and 250 

 slaves. The parish now contains only 2, 880 acres ; 2,340 having 

 been slowly denuded away by the action and encroachment of 



