Reports and Proceedings. 79 



sustained by the area under consideration were chiefly those of land- 

 ice, while its limited extent and rapid attenuation in all directions 

 from the Cromer coast have led him to infer that only a small part 

 of England was under water at the time. On the other hand, the 

 great masses of chalk and of chalky debris that were carried into the 

 marine sediment appear to indicate the presence, near at hand, of 

 some terrestrial chalk-area from which they were detached, and he 

 stated his belief that during this period much of the chalk of Norfolk 

 was covered by a great glacier. In illustration of this view Mr. 

 Searles Wood described a section at Litcham, in which the Chalk- 

 with-flintbands is seen to become gradually more impure towards the 

 surface, the flints becoming at the same time detached and scattered, 

 this disturbance having been produced, in his opinion, by a force 

 acting downwards from the surface, and becoming less powerful the 

 deeper the section descends. 



3. " On the evidence of a third Boulder-clay in Norfolk." By 

 F. W. Harmer, Esq. Communicated by Searles V. Wood, Jun., Esq., 

 F.G.S. 



The author described a deposit of true boulder-clay, from nine to 

 fifteen feet in thickness, resting on the chalk, and occurring at a 

 slight elevation above the bottom of the valley of the Yare. It 

 seemed to him to be distinct in age both from the till of the Cromer 

 cliffs and from the much more recent boulder-clay, which caps the 

 high land on each side of the valley ; and he gave sections which 

 appeared to prove that it is posterior in age, not only to the boulder- 

 clay, but also to the plateau-gravel capping the middle drift, by the 

 time necessary for the erosion of the deep valley in which it occurs. 



GrEOLOGicAL SociETY OF LoNDON. — II. January 9, 1867. — Waring- 

 ton W. Smyth, Esq., M.A„ F.E.S., President, in the Chair. The 

 following communication was read : — 



" On the age of the Lower Brick-earths of the Thames Valley " 

 By W. Boyd Dawkins, M.A. (Oxon), F.G.S. 



The Lower Brick-earths of the Thames Valley have been a fertile 

 source of discussion since the year 1836, Dr. Falconer considering 

 them to be anterior in age to the boulder-clay, Mr. Prestwich 

 believing them to belong to the Low-level series of Quaternary 

 deposits. The author divides the evidence upon this question into 

 two heads — Physical and Paleeontological. The sections at Ilford, 

 Grays' Thurrock, Crayford, and Erith, evince the same sequence of 

 deposits. At the bottom of all are the fluviatile brick-earths and 

 gravels, whence the moUusca and mammalia are derived, and which 

 are remarkable for the horizontality of their bedding and the even 

 sorting of the component parts. Lying on the eroded top of these 

 is a deposit — the trail of Mr. Fisher — of a highly confused nature, 

 containing stones, often with their long axes arched, and never 

 sorted by the action of water. It contains also many stones and 

 boulders that could only have been floated to their present situation 

 by ice. It is as remarkable for the contortion of its bedding as the 

 deposits below are for their horizontality. On its uneven summit 



