5t>8 Geological Society: — 



, I Contorted Drift. 



Sands and Gravels (Middle Glacial ?). 

 Bedded sand and marl. 

 Sedimentary Boulder- clay 

 Fine Sands. 

 2nd Till (nnstratified Boulder-clay). 

 Intermediate Beds (laminated marl &c), 

 1st Till (nnstratified Boulder-clay). 

 Arctic Freshwater Bed. 



The beds below the 1st Till were not described ; the 1st and 2nd 

 Tills were considered to have been formed by land-ice coming from 

 the W. or W.N.W. ; while the Intermediate Beds appear to be 

 stratified glacier-mud deposited on the retreat of the ice. The 

 Sands are probably marine ; and so also appear to be the Contorted 

 Drift and Middle Glacial. Glacial beds later than the Chalky 

 Boulder-clay appear to be represented near Cromer by valley- 

 deposits which were not treated of in this paper. 



In dealing with the question of the age and mode of formation of 

 the contortions, the author pointed out that all, with the doubtful 

 exception of a few of the smaller ones, affected not only the Con- 

 torted Drift but also the Middle Glacial, while, at the same time, 

 contortions affecting the overlying beds were often much more com- 

 plicated at the base, and rested on an even, undisturbed surface of 

 the Preglacial beds. This he accounted for by considering the con- 

 tortions to be formed by an advancing ice-sheet, which pushed 

 before it a mound of the older glacial beds, while the beds below 

 the level of the base of the ice were undisturbed ; thus the junction 

 of the contorted and uncontorted beds is a horizontal fault-line. 

 The ice-sheet he referred to the period of the Chalky Boulder- clay. 



The author drew attention to the fact that the hollows in which the 

 Middle Glacial gravels rest are in every instance due to contortion, 

 and not to erosion. The large masses of chalk in Boulder- clay 

 were considered to have been torn off by the same force that pro- 

 duced the contortions. 



11. " On a Disturbance of the Chalk at Trowse, near Norwich." 

 By Horace B. Woodward, Esq., F.G.S. 



Attention was drawn to a section at Trowse, where the Chalk with 

 bands of flint was uplifted at an angle of about 37°. Abutting 

 against the Chalk was a mass of the same rock rearranged, con- 

 taining broken flints, and pebbles of flint, quartz, and quartzite. 

 This rearranged Chalk was traced underneath the uplifted beds ; 

 and the author gave reasons for believing that the disturbance was 

 produced by the agent (land ice) which formed the Chalky Boulder- 

 clay. Allusion was made to many cases of glaciated Chalk in 

 Norfolk, and to the cervine and other organic remains occasionally 

 met with in it. Comparing the Trowse section with that at 

 Litcham, described by Mr. S. V. Wood, Jun., the author came to 

 the conclusion that this was a similar and striking instance of the 

 incipient formation of a huge Chalk boulder, serving to throw light 

 on the origin of the large transported masses seen in the Cromer cliffs. 



