﻿170 Geological Society : — 



above explanation. Passing over that ' north of Heed ' as un- 

 important, we come to the Pinner's Cross Pit. Here the Boulder- 

 Clay is not, strictly speaking, ' banked-up ' against the Chalk, 

 as stated by Mr. Woodward, but occupies a hollow in the Chalk, as 

 described by the late Mr. Penning. The Chalk has a fairly-high 

 dip, but there is little other sign of mechanical disturbance. In the 

 pit south-west of Newsell's Park, a shear-plane can indeed be seen 

 in one face, which, however, is explicable by ordinary faulting ; and 

 on the same face there are (or were) some small clayey patches. 

 A few yards farther to the south-east, Boulder-Clay appears above 

 the floor of the pit, filling an arched cavity. This is, no doubt, a 

 singular position, but there is nothing to show that the Chalk has 

 been thrust over the Clay. The author suggests that, as in Mden 

 and occasionally in Eiigen, the Clay has been carried down from 

 above into cavities already formed in the Chalk, and quotes a case 

 from the latter island of a clay-filled cavity, which was connected 

 with the surface and might have yielded a section like that in the 

 above-named pit. Penning's diagram shows (probably nearly over 

 this spot) Boulder-Clay resting upon the Chalk. So the author 

 maintains that, even if the fundamental hypotheses be true, they 

 are not applicable to these sections. 



3. ' Brachiopod Homceomorphy : Pygope, Antinomia, Pygites.' 

 By S. S. Buckman, E.G.S. 



April 4th. — R. S. Herries, M.A., Vice-President, 

 in the Chair. 



The following communications were read : — 



1. ' On a Case of Unconformity and Thrust in the Coal-Measures 

 of Northumberland.' By Prof. G. A. L. Lebour, M.A., M.Sc, F.G.S., 

 and J. A. Smythe, M.Sc, Ph.D. 



The sections described occur on the coast north of the Tyne, near 

 Whitley Sands, between Table Rocks and Briar-Dene Burn. The 

 base of the ' Table-Rocks Sandstone' is found to rest unconformably 

 upon a series of alternating shales and sandstones, among which 

 is a well-marked band of clay-ironstone crowded with Carbonicola 

 acuta, one of those ' mussel-bands ' which are found to be perhaps 

 the most remarkably-persistent strata in the North-of-England 

 Carboniferous rocks. According to the correlation of the Geological 

 Survey, this particular band is the one that is well known as 

 occurring a little way above the Low-Main coal-seam. The entire 

 junction, so far as it can be seen at the base of the cliffs and on the 

 foreshore, many parts of which are only swept clear during 

 exceptional weather, has been studied as opportunity offered during 



