PREFACE. 
The Geological Survey Map of England and Wales having been 
completed, it has now become possible to collate the work done by 
the Survey and by other observers in the different geological 
formations of the kingdom, and to prepare the general strath 
graphical memoirs^ to which the local or sheet-memoirs hitherto 
published were intended to be introductory. These general 
memoirs are designed to present a compendium of all that is known 
reffardino; each of the geological formations in its distribution 
through the United Kingdom. They will thus include the con¬ 
densed results of the labours of the Geological Survey, with full 
reference to the maps and sheet-memoirs where local details have 
already been given. It will be impossible to follow the strict 
stratigraphical sequence in their publication. They will be issued 
in the order in which they can be most speedily prepared. 
The present work is the first of these stratigraphical memoirs. 
It has been written by Mr. Clement Keid, and is designed not 
only to bring together the results of the work of the Geological 
Survey among the Pliocene deposits, but to present a faithful 
summary of the present state of knowledge regarding that portion 
of the Geological Record in this country. In pursuance of this 
design full use has been made of the maps, memoirs, and un¬ 
published work which the Survey has accumulated during the 
progress of the mapping in the eastern counties. Among the 
members of the Survey whose labours have been of special service 
in the preparation of this volume reference may be made to 
Messrs. Whitaker, Woodward, Dalton, Blake, and E. T. Newton. 
Fuller acknowledgment of the work of these observers, and of 
others outside of the Survey, will be found in the text. 
While ths work was in preparation Mr. Reid, who had himself 
mapped considerable tracts of nevv^er Pliocene deposits in Norfolk, 
made a careful examination of the disputed Lenham deposits, 
collected a considerable number of shells from them, and I think 
finally settled their relative geological age—a question of great 
importance, not only in regard to the general Pliocene succession 
in England, but also of singular interest in regard to the later 
Tertiary and post-Tertiary terrestrial movements in western 
Europe. He also studied the deposits at St. Erth, St. Agnes 
Beacon, and Dewlish. 
It appeared to me eminently desirable that, besides examining 
the English Pliocene strata, the author of this work should have 
an opportunity of comparing them with some of their best known 
and most important Continental equivalents. He was accordingly 
sent to make a series of observations in Belgium, France, and 
Italy, and the results of jfchese journeys are embodied in the follow¬ 
ing chapters. Having thus gained an enlarged experience among 
the younger Tertiary deposits of western and southern Europe, 
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