284 Reports and Proceedings — 



conglomerate of Shropshire seemed to indicate that the Malvernian 

 schists were older Archaean. 



IL— April 27, 1887.— Professor J. W. Judd, F.E.S., President, 

 in the Chair. — The following communications were read : — 



1. " On the London Clay and Bagshot Beds of Aldershot." By 

 H. G. Lyons, Esq., E.E., F.G.S. 



The author first described the section from Thorn Hill on the 

 N. to Eedan Hill on the S., plotted from the 6-in. Ordnance Survey 

 on a scale of 6 in. to 1 mile horizontal, and 12 in. to 1 mile vertical. 

 This section comprises beds from the Woolwich and Beading series 

 to the Upper Bagshot inclusive. He showed a dip of 2J° to the N. 

 which is regular or nearly so throughout. A few feet of Upper 

 Bagshots occur on Thorn Hill (365 feet) ; at the base of these the 

 Pebble-Bed crops out, forming also much of the surface of the South 

 Camp. The Middle Bagshots on the south slope of the hill are 

 estimated from the South Camp boring at 53 feet, with a marked 

 clay-bed at the base; and below these a few feet of the Lower 

 Bagshots are exposed in the intervening valley. The greater part of 

 Eedan Hill (364 feet) is made up of Lower Bagshots ; but towards 

 the top a few feet of the basal clays of the Middle Bagshots have 

 been exposed by a recent trench. Although the elevation is prac- 

 tically the same as that of Thorn Hill, the rest of the Bagshot series 

 is cut out owing to the northerly dip. These results differ from 

 those of previous observers, e.g. the Geological Survey carry the 

 Lower Bagshots to the top of the Eedan Hill, as do Messrs. Monck- 

 ton and Herries ; whilst of the anticlinal, alleged by Mr. Irving to 

 exist in this traverse, there appears to be no trace. The author 

 also observed that the arguments for overlap of the upper beds and 

 for the erosion of the London Clay are not borne out by the facts. 



The second section described runs from Gravel-Pit Hill on the N. 

 to Ash Green on the S. It was drawn to the same scale, and showed 

 the beds from the Chalk to the Middle Bagshots inclusive. Dip 

 northerly 21° to 2° 50' at south end. A spur of the Fox Hills 

 (Gravel-Pit Hill) is seen to consist of Upper Bagshots of the normal 

 type down to the lower shoulder of the spur, which is capped by the 

 Pebble-beds marking the junction of the Upper and Middle Bag- 

 shots. The Ash-station well shows the basement-beds of the Lower 

 Bagshots, of a character very similar to those in the Brookwood and 

 South-Camp deep boring. The position of the outcrop of the London 

 Clay also is in favour of a regular and persistent northerly dip, 

 corresponding in degree with that given at East Wyke farm by 

 Messrs. Monckton and Berries. The thickness of the London Clay 

 was calculated at 330 feet, which is about the same as at South 

 Camp, leaving no margin for its erosion before the deposition of the 

 Bagshots. — The third section was drawn, also on the same scale, 

 through Aldershot town, showing the beds from the Woolwich and 

 Eeading series to the Middle Bagshots inclusive. The dip is 21° 

 to the N., and regular, as in the other two cases. The following 

 thicknesses are given :-^— 



