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NOTICE 



(By H. W. Bristow, F.E.S.) 



The original survey of the Isle of Wight on the one-inch scale 

 was commenced under the personal superintendence of Sir Henry 

 T. De la Beche in the year 1848, and was carried on at intervals 

 between that year and 1856 by the late Professor Edward Forbes 

 and myself, Mr. W. T. Aveline at the same time completing a 

 portion of the Secondary area between Ohale and Dunnose, the 

 whole being under the direction of Professor A. C. Ramsay. 

 During part of the time that the Island was being surveyed 

 assistance was rendered by the late Mr. R. A. C. Godwin-Austen, 

 Mr. Henry Keeping (now of the Woodwardian Museum, 

 Cambridge), and by the Fossil Collectors, Richard Gibbs and 

 John Cotton. 



A re-survey of the Island on the six-inch scale instituted by the 

 present Director-General was begun in November 1886, and was 

 completed by the end of the year 1887, the northern or Tertiary 

 half of the Island being mapped by Mr. C. Reid, and the southern 

 or Secondary half by Mr. A. Strahan. This re-survey, reduced to 

 the new one-inch Ordnance Map, was published in 1888. Clean 

 copies of the six-inch Maps have been deposited in the Geological 

 Survey Office for reference, and a duplicate set of these sheets, 

 mounted as a wall-map, was exhibited at the International 

 Geological Congress in 1888, and is now suspended in the Museum 

 of Practical Geology. 



The first edition of the present Memoir was published in 1862. 

 It was written by myself by desire of the late Sir Roderick J, 

 Murchiscn, then Director-General, use being made, when neces- 

 sary, of the posthumous Memoir on the Fluvio-marine Formation 

 of the Isle of Wigiit by Professor E. Forbes, in which some of 

 the notes I had made had already appeared. In the preparation 

 of the present edition of the Memoir the authorship of the 

 revision has followed the same general distribution as in the case 

 of the mapping. The account of the Secondary rocks has been 

 revised and enlarged by Mr. Strahan, who, besides examining 

 these rocks in the Isle of Wight, continued the mapping of their 

 subdivisions into the neighbouring coast of Dorsetshire. The com- 

 parisons with the Geology of the mainland made in the following 

 account of the Secondary rocks are thus entirely his. 



The chapters on the Tertiary rocks have been revised and 

 much enlarged by Mr. Reid, The most important change which 

 he has been able to make in the Map, the great extension he has 

 given to the Hamstead Beds, has been rendered possible by the 

 application of a boring apparatus, whereby no fewer than 358 

 borings, ranging from 10 to 33 feet in depth, were made in the 

 Tertiary area of the Island. 



