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ii 



PREFACE TO THE FIRST EDITION. 



rba^cbk^f ^the hand-coloured edition of the one-inch 

 Geological Map of London and its Environs having made it 

 desirable to issue a less expensive map, the present colour- 

 printed edition, covering almost the same area, was published 

 in four sheets in 1903. Though largely founded on the work of 

 Mr. Whitaker and his colleagues, as depicted on the earlier 

 map, the new sheets include the results of a six-inch survey 

 of parts of the Thames Valley, made in 1902 by Mr. T. I. 

 Pocock and Mr. J. Allen Howe. 



Mr. Woodward, who had taken part in the original Drift 

 Survey of the area, superintended the progress of the new work, 

 but owing to the pressure of other duties, was unable to write 

 the necessary descriptive memoir during his official connection 

 with the Survey. He very kindly volunteered to do this after 

 his retirement, and the present volume is the result. 



" The Guide to the Geology of London and the Neighbour- 

 hood," prepared by Mr. Whitaker and published in 1875, dealt 

 with the area contained in the older map of London and its 

 Environs. This work reached its sixth edition in 1901 and is 

 now out of print. The present memoir describes the slightly 

 smaller area embraced in the new map. While avoiding local 

 detail, the author discusses generally the characters of the 

 geological formations, and summarises the most recent views on 

 the various problems presented by them. For this purpose he 

 has revisited many parts of the area, and has also taken the 

 opportunity to collect records of new sections. 



No one can write on the geology of the neighbourhood of 

 London without being indebted to the work of the late Sir J. 

 Prestwich and of Mr. Whitaker. In the early memoir on 

 " The Geology of the London Basin," and in the two volumes on 

 :< The Geology of London," Mr. Whitaker not only recorded all 

 the facts gathered during the progress of the Geological Survey, 

 but dealt fully with the observations of other geologists, adding 

 his own criticism on divergent views. During the twenty years 

 which have elapsed since the publication of the Geology of 

 London much has been added to our knowledge, especially of 

 the Plateau Drifts and the deposits of the Thames Valley, by the 

 labours of Mr. M. A. C. Hinton, Mr. T. V. Holmes, Mr. A. S. 

 Kennard, Mr. H. W. Monckton, Mr. E. T. Newton, Dr. A. E. 

 Salter, Mr. S. H. Warren, and Mr. B. B. Woodward. The Chalk, 

 during the same period, has been more particularly the subject 

 of investigation by Mr. G. E. Dibley and Mr. G. W. Young. 

 Though no effort has been spared by Mr. Woodward to 

 acknowledge the sources of information, it has proved to be 

 impossible to do justice to the voluminous literature within the 

 limits of so small a memoir. 



