Vol. 55.] CHALK AND DRIFT IX MOEN AND EUGEN. 325 



to abstain from discussing the origin of the Drifts in the area. He 

 complimented them upon their ingenious explanation of the pheno- 

 mena described, but thought that a simpler one might have been 

 adopted. He called attention to the huge transported masses of 

 Secondary rocks included in the Drift at various points along the 

 British margin of the North Sea, from Aberdeenshire to Norfolk, 

 which prove that, whatever might be the nature of the glacial 

 agency, it was capable of disturbing and detaching portions of the 

 solid strata ; and he thought that the sections which illustrated 

 the paper demonstrated the first stages of this process. He asked 

 the Authors whether they could give any information regarding the 

 shells which had been said to occur in these Drifts. 



Mr, A. E. Saltee asked whether it was not possible to regard 

 these deposits as fluviatile accumulations, derived from old and 

 extensive drainage-areas, now greatly curtailed and altered by 

 marine and subaerial agencies. The occurrence of a cold period 

 in former times, and the presence of these curious Drifts on a rock 

 soluble in water, might have brought about the complicated phe- 

 nomena observed. 



Prof. Seeley said that, although these interesting sections are 

 not exactly paralleled in this country, it is not improbable that 

 they are only intenser manifestations of the familiar relations of 

 the Chalk of Britain to the Drift. When the Midland Eailway was 

 made from Luton northward, a bed of black clay was exposed 

 about 1 foot thick, apparently interstratified in the upper part of 

 the section, which might perhaps have been introduced from the 

 surface. The examples of beds of sand in the Chalk which were 

 introduced by means of pipes were more common. In the south of 

 Essex, not far from the Boulder Clay, a railway-section some ten 

 years since showed the Chalk bent into several undulations or corru- 

 gations in which the ancient gravels above it participated, and 

 where the Chalk ended to the south, other giavel-beds and clays 

 were highly inclined. The faults in the Thames Valley Chalk, 

 although on a small scale, were so numerous that they suggested 

 the intercalation of the Drift with the Chalk when denudation has 

 not removed the whole of the Drift from faulted surfaces. No one 

 explanation need be relied upon when the circumstances indicated 

 local alternatives. 



Mr. E,. M. Brydone observed that the gradual sinking of a level 

 bed of Drift into a ravine would result in the lowest bed of the 

 Drift coating both sides of the ravine, instead of bringing the top- 

 most bed of the Drift in close contact with one side of the ravine, as 

 shown in some of the diagrams. 



Mr. Strahan was relieved to find that be was not called upon to 

 believe in wholesale post- Glacial folding of strata. The Authors had 

 stated that no comparison was possible between the cliffs of these 

 Baltic islands and those of Cromer, but their diagrams strongly 

 reminded him of what he had seen of the Chalk-masses and 

 undercutting Drifts in the Norfolk cliffs. He asked for further 

 explanation of the difference insisted on by the Authors. 



