OIT THE NEWER PLIOCENE PERIOD IN ENGLA.ND. 457 



35. The Kewer Pliocene Period m Engla.nd. By Searles 

 Y. Wood, Jun., F.G.S. (Read March 24, 1880.) 



[Plate XXI.] 



In Two Parts. 



Part 1, comprising the Eed and Pluvio-marine Crag and the G-lacial 



formations. 

 Part 2, comprising the Postglacial formations. 



Part 1. 



Stage I. The Red and Fluvio-marine Crag. 



The movements by which the conditions of sea and land have changed 

 in England from the time when the Eed Crag began to form appear 

 to me to have been so continuous that the formations from this 

 point onwards can be studied with advantage only as one geological 

 group ; and as these have all accumulated during one great move- 

 ment of depression and reelevation, the ^ewer Pliocene period seems 

 to me the most suitable term for the lapse of time which they mark. 



The commencement of this Crag in England is marked by the 

 accumulation of those beds of which a small remnant is preserved 

 in the cliff at Walton Naze. During its progress the continuous 

 destruction of the antecedent accumulations of the same forma- 

 tion, as well as of the beds of the Coralline Crag, furnished 

 that peculiar mass of comminuted shell of which the successive 

 portions of the formation are made up. The character of ths 

 beds, and the highly and often continuously oblique character of 

 the bedding, with other evidence on which I do not stop here to 

 dwell, indicate that nearly all that part of the formation to which 

 the term Red Crag (as distinguished from the part represented by 

 the Chillesford beds) has been applied was accumulated between 

 high- and low-water marks, when the rise and fall of the tide was 

 considerable. 



The Walton bed, as my father has shown, is destitute of many 

 species of MoUusca which occur in the Red Crag of the northern 

 (or Butley and Chillesford) extremity of the formation, while the 

 beds occupying the intervening area afford some, though but slight, 

 evidence of the horizontal transition between the two. These 

 species are either those of Arctic habitat, or those which, having 

 since become extinct, lived nevertheless into that succeeding period 

 when the evidences of glacial conditions of climate become con- 

 spicuous. I^ow while this is the case with the fauna, it is im- 

 portant and confirmatory to find, as is the case, that though at its 

 northern extremity (^. e. at Butley and Chillesford) the Red Crag 

 passes uninterruptedly upwards into the Chillesford Clay, the reverse 

 of this is the case at the southern (or Walton) extremity, if the bed 

 of laminated clay, which there overspreads the Crag, be the Chilles- 



Q. J. G. S. No. 144. 2. x 



