776 THE PLIOCENE DEPOSITS OE HOLLAND. [NOV. 1 896. 



this basin was filled by ihe waters of a shallow sea, the boundaries 

 of which travelled now and again in a northerly direction. Its 

 position to-day is similar to that which it occupied during the 

 Scaldisien period, except that it is connected with the S.W. by the 

 Straits of Dover, and that near its western margin have accumu- 

 lated the Glacial beds of Norfolk and Suffolk, and in its eastern 

 portion material brought into it by the Rhine and the Scandinavian 

 ice. 



The hypothesis of a permanent basin with shifting shore-lines 

 seems to be in accordance with all the facts of the case. It affords a 

 possible explanation of the character and disposition of the various 

 Crag beds of the East of England, and enables us to arrange them 

 in order, as members of a continuous and closely-connected series. 

 The western shore of the Newer Pliocene gulf extended at no time 

 far beyond the present English coast, and hence the shallow-water 

 beds of Norfolk and Suffolk, originating at no great distance from 

 the shore, and following from time to time the shifting margin of the 

 sea, give us information as to the various changes which have there 

 taken place in the distribution of land and water. The strata 

 revealed by the Dutch borings, on the contrary, were deposited 

 farther from land and in a subsiding area, and therefore, while they 

 throw no light upon the geographical conditions of the eastern 

 portion of the basin, they afford a vertical sequence of beds 

 representing continuously a considerable portion of the Pliocene 

 «poch. It may be hoped that from this almost unexplored field 

 most important results may hereafter be gained. 



The lines which I have drawn to show the possible distribution 

 of land and water during the successive stages of the Crag period 

 must be regarded as only tentative, but even if my suggestions afford 

 no solid and permanent resting-place, they may at least serve as 

 stepping-stones to firmer ground, and to a position whence we may 

 obtain clearer light on some of the problems of the later Tertiary 

 geology of East Anglia. 



Lists of the shells obtained from the different Dutch borings, 

 arranged according to the classification adopted in this paper, are 

 given, showing the resemblance of the different faunas to those of 

 the different horizons of the English and Belgian Crags, and the 

 comparative abundance of the different species in each. 1 



These lists, which contain the names of all the species at present 

 known from the Pliocene beds of Holland, are arranged to show at 

 a glance the much closer resemblance between the Amstelien and 

 the Upper Crag than to the Scaldisien or the "Walton bed. Two 

 schedules are given : the first containing those species which occur 



1 My best thanks are due to Mr. P. F. Kendall, F.G.S., who, with the late 

 Mr. R. Bell, spent much time and labour in working out the Walton fauna, for 

 allowing me to supplement my own knowledge of this formation by the 

 examination of a list of the Walton mollusca which he is preparing for 

 publication, and also to my good friends in Belgium, Holland, and at 

 Jermyn Street for their courtesy in placing so willingly at my disposal their 

 stores of information. 



