168 SECTIOIfS BETWEEN LINCOLN AND CHESTERFIELD. [May 1898,- 



He also enquired whether the Marl Slates and the Permian 

 breccias were found in the section. He considered that the 

 phenomena, which the Author referred to a landslip, illustrated 

 very well on a minute scale what happened when a thrust-plane 

 was produced. 



Mr. Lamplugh thought that, with regard to the Glacial deposits, 

 the field -evidence on both sides of England showed that duriug the 

 maximum glaciation, the chief accretive and radiant centres of the 

 ice-sheet lay over the basins of the North and Irish Seas, the com- 

 paratively low topography of the surrounding land being practically 

 obliterated. Under these conditions the rarity or absence of drift- 

 deposits in the area described by the Author might readily be 

 explained, since this part of England would lie between, or near, 

 the margin of the two great ice-lobes. 



The Peesident and Mr. Whitaker also spoke. 



The Author, in reply, said that the beds described in the Trent 

 valley are alluvial and not Glacial. With regard to the absence of 

 drift, not being acquainted with the surrounding country, he could 

 only speak for the railway-section. The section figured near Parson's 

 Wood very much resembles an unconformity, but the exposure is 

 not extensive enough to allow of a definite expression of opinion. 



.V J 



