NEWLY EXPOSED SECTIONS AT READING. 457 



position of the seven sections, the extent of the blue shale, or leaf-bed, 

 together with that of the lower series of clay -galls (small) in the sands, 

 and of the higher (larger) rolled lumps of clay on the bed of shale. 

 Fig. 4. Sections Nos. 5, 4, 3, 2, 6, & 7 in their order. 



Nos. 6 & 7 here take the place of Section No. 1. 



Discussion. 



Mr. Whitaker said that this careful noting of local features in 

 such very varying sections was of great value, and hoped that 

 geologists would continue to study the sections near Heading. The 

 occurrence of clay-galls, or rolled pieces of clay, was interesting ; 

 some of them were, he thought, certainly derived from the destruc- 

 tion of previously existing beds ; hut others may possibly have been 

 only isolated patches of some attenuated clay bands. Good examples 

 of rolled clay may be seen on any clay shore, as at Sheppey and 

 elsewhere. 



Prof. Seeley stated that he had noticed the lumps of rolled clay 

 at Beading, and that he had seen similar balls of clay derived from 

 the Kimmeridge Clay in the marine gravel at Hunstanton. With 

 regard to the " bottom-bed," he was inclined to believe that it con- 

 stitutes an abnormal form of the Thanet Sands, being composed of 

 quartz-sand, whilst the sands of the upper beds are mainly derived 

 from flint. 



Mr. Evans remarked that the denudation and reconstruction of 

 beds seemed to be due to alterations of level. It was more sur- 

 prising, at first sight, that the Oyster-beds, with their accompanying 

 overlying strata, could be traced over areas so wide apart, than that 

 even many local denudations and reconstructions should be observ- 

 able. Still these latter furnished important evidence as to the his- 

 tory of the deposits. 



Prof. Rupert Jones explained that the large clay-galls, with and 

 without enclosed flints, in the sand over the blue clay, lay about in 

 great numbers, having been exposed and left by the workmen in 

 moving the sand last summer. In the case of the smaller clay- 

 galls at a lower level, the associated drifted flints, lydite and lig- 

 nite, supported the idea of their having also been derived from 

 other beds. 



