VOL. XVII. (i) EXCURSION— CHEPSTOW 17 



westwards, thrusting . tongues of water up the valleys, forming creeks that 

 were margined with the pebbly beaches or screes that eventually became 

 cemented together to form the " Dolomitic Conglomerate." Thus while 

 " Dolomitic Conglomerate " was formed along and near the shore, ordinary 

 red marl was laid down further out. The area continued for a time to sink, 

 but at the close of Triassic times there was probably a slight movement 

 of elevation, owing to which certain Rhaetic deposits were not laid down 

 in the Chepstow district. At the time of formation of the Rhaetic Bone-Bed, 

 however, subsidence set in, and the oncoming Rhaetic sea worked up the top- 

 layer of the tea-green marl and enclosed the water-worn nodular-masses in a 

 matrix of sand and fish-remains. The deposit of black shales (Pteria-contorta- 

 Beds), pale-green marls and limestones, including the Cotham Marble, 

 followed ; but then there was a slight uplift again. This is known to have 

 been the case, because there is no White Lias at Sedbury Cliff (PI. III. fig. 2), 

 and the representative of the Cotham INIarble there occurs generally in the 

 form of a conglomerate adherent to the basal layer of the Ostrea-Beds. The 

 Ostrea-Beds and the same kind of alternations of Lower-Lias limestones and 

 clays, as at Lavernock Point, near Penarth, complete the section. Pieces of 

 the Bone-Bed were collected, and a fine slab of the Pleurophorus-Bed 

 was exhibited. Large pieces of the basal Ostrea-Bed limestone were seen 

 with the conglomerate adherent to its under-side, and it was generally agreed 

 that this bed constituted the most interesting feature of the Sedbury 

 ClifE section. I 



The Severn Salmon "is less abundant than it was in past generations. 

 . . . The chief method of taking the fish is by nets. The fisherman moors 

 his boat across the tide, and fixes his net in such a manner that the 

 bag is carried under the boat by the current ; he holds a string attached to 

 the net in his hand, and as soon as he feels a fish he hoists up the net. 

 Another method, which has been practised from the eariiest times in the 

 parishes of Tidenham and Woolaston, is that of ' potchers,' or more correctly, 

 ' putchers.' A long stand of baskets is erected below high-water mark, tier 

 over tier ; the baskets are long and cone-shaped, and open at the base of the 

 cone. The open end faces the incoming tide, and the fish swimming up the 

 river enter these baskets, and being unable to turn round owing to the narrow 

 dimensions of the potcher, are left high and dry by the receding waters. It 

 need hardly be added that the privilege of erecting potchers has long been 

 limited." ("Gloucestershire," Cambridge County Geographies, 1909, pp. 

 40, 41). 



Driving down to the once oft-frequented ' ' passage ' ' at Beachley, the 

 Members walked to a spot on the promontory opposite to the rock on which 

 are the ruins of St Tecla's Chapel. It was first of all pointed out that the 

 Beachley peninsula is composed of red Keuper Marls, faulted against Car- 

 boniferous Limeston,e — the latter presenting a bold face to the Severn 

 estuary. A few of the Members returned along the shore, and noticed the 

 veins mainly of quartz in the red marls, and the masses of Carboniferous 

 Limestone jutting up in the beach. 



Driving back into Chepstow, the Members went to the Beaufort Arms 

 Hotel, where the President entertained them at lunch. 



After lunch, Mr W. Crooke proposed, and Mr Vincent A. Smith seconded, 

 that a hearty vote of thanks be accorded to the President for his bounteous 

 hospitality, and referred in eulogistic terms to the energy and enthusiasm 

 with which he had initiated and forwarded the scheme for the preparation of 

 a County Flora. 



I L.R., Quart. Joum. Geol. Soc, vol. Ix. (1903), pp. 390-395 and pi. xxiv. See also Dr A. 

 Vaughan, Quart. Joum. Geol. Soc, vol. Ix. (1903), pp. 396-402. 



