Geological Society of London. 217 



5. "On Abnormal conditions of Secondary Deposits when con- 

 nected with the Somersetshire and South Wales Coal -basins; and 

 on the age of the Sutton and Southerndown series." By Charles 

 Moore, Esq., F.G.S. 



The author first describes the geological constitution of the Mendip 

 Hills, which, in his opinion, were vipheaved by the intrusion of a 

 basaltic dyke (now noticed for the first time) during the period of 

 the Upper Trias. The Mendip chain proved an island-barrier to the 

 incursion of the deeper sea-deposits of the south, on which lived the 

 Microlestes and other terrestrial animals. Along the south side of 

 this barrier shore-deposits were formed, the " Carboniferous Lime- 

 stone " constituting the floor of the ocean at that time. 



He then instituted a comparison between the Ehtetic and Liassic 

 formations within and those without the Somersetshire coal-basin. 

 The thickness of the beds, from the Trias to the Inferior Oolite, was 

 stated to be, outside the coal-field, 3320 feet, whilst inside it was 

 only 169 feet. These results were obtained from an examination of 

 numerous sections, which were described in detail by the author. 



After considering the horizontal deposits beyond the Mendips, and 

 the unconformable conditions within its coal-basin, the author dis- 

 cussed the abnormal conditions which are presented by deposits of 

 the same age, when they are intimately connected with the " Car- 

 boniferous Limestone." In the Charterhouse lead-mine a deposit of 

 clay, twelve feet in thickness, and containing Liassic shells, was stated 

 to occur at a depth of 260 feet in the Carboniferous Limestone. 



Among the organic remains, three species of terrestrial shells, 

 referable to the genera Helix, Vertigo, and Proserpina, and a Chara- 

 seed, were discovered.^ 



The author concluded by pointing out the peculiarities presented 

 by the Liassic strata in Grlamorganshire, with special reference to the 

 stratigraphical position of the Sutton Stone and the Conglomerates 

 of Brocastle, etc. 



IL— April 3, 1866.— Warington W. Smyth, Esq., M.A., F.K.S., 



President, in the Chair. The following communications were read : 

 1. " Eemarks on the Drift in a part of Warwickshire, and on the 

 evidence of glacial action which it afi"ords." By the Eev. P. B. 

 Brodie, M.A., F.G.S. 



The later Drift-deposits in the district treated of occur along the 

 valley of the Avon, and consist of the usual sands and gravels, with 

 Mammalian remains ; but as yet no Flint Implements have been 

 discovered in them. The author enumerated the different kinds of 

 rock represented by pebbles or fossils in the gravel, and referred to 

 the abundance of flints, and the occasional occurrence of pieces of 

 chalk in the gravel as proof that their mode of conveyance was by 

 icebergs, unless it be conceded that the Cretaceous formation at one 

 time had a much further extension northwards. The abundant 



^ Since the reading of this paper, Mr. Moore writes me (April 7th), " Additional 

 evidence in confirmation of a Mendip land-area has turned up, namely, shells of 

 I'lanorbis, falvata, and Eydrobia ; also from the Charterhouse mine." — Edit. 



