Clifton CoUege Scientijic Society. 21 



the west ; first comes the island of Caldy, and at low water a 

 ridge of rocks can be seen extending from Caldy Point, to the 

 opposite point of St Margaret's Island. At the South Sand's gate 

 or archway commence the ruined walls and towers of the castle. 

 A low irregular wall extends round the Castle Hill on the verge 

 of its clifF, while the hill itself, gradually rising, is surmounted by 

 a keep. "The crescent sweep of the north side of the town, with 

 the cemetery chapel, is seen beyond. The steep North Cliffs rise 

 from the beach below, and terminate in an irregularly formed 

 projection called Monhstone. Beyond this point is the bay of 

 Saundersfoot with Amrotli Castle. 



Tenby is a market-town and municipal borough of great anti- 

 quity, and, conjointly with Pembroke, Milford, and Wiston, returns 

 a member to Parliament. 



Geology. — To the north of the town lie the coal measures, which 

 yield anthracite coal. The so-called beetlestones (found on the 

 north shore towards Saundersfoot) are nodules of clay-ironstone, 

 the centre or nucleus of which appears to have been sometimes 

 animal, sometimes vegetable. The mountain limestone lies to the 

 south of the town. The old red sandstone commences at Skrinkle 

 Bay ; but few characteristic fossils of this formation have as yet 

 been discovered in Pembrokeshire. The Silurian formation suc- 

 ceeds in due order, so remarkable for that strange extinct crus- 

 tacean the Trilohite. The tails of the two species of these occur- 

 ring here seem to identify them with the lower beds. The coal- 

 basin of Pembrokeshire extends from Saundersfoot westward to 

 Milford Haven. The coal of this district is all anthracite or 

 stone-coal ; while the veins of the clay lying above and beneath 

 the coal are full of the roots and stems of the stigmaria and 

 other plants. 



The remains of a submerged forest may be seen on the shore 

 near Araroth at low spring-tides ; the wood is nearly all decayed, 

 and on being touched crumbles to pieces. Tradition makes men- 

 tion of a sunken tract of land called the Lowland Hundred, 

 (Cantrev y Gioaelod), said to have been situated off the northern 

 coast of the county, and to have occupied a considerable portion 

 of what is now Cardigan Bay. This tract of country was pro- 

 bably lost by the subsidence of the land, and not, as might be con- 

 jectured, by neglecting the sluices. The coast near Amroth and 

 Saundersfoot seems to have undergone thi'ee distinct changes at 

 three different periods, for by digging at low water below the 

 remains of the forest then exposed, a sea-beach is found. From 

 this we may infer that at one period the beach now deeply sub- 

 merged must have been level with the sea ; at a second period this 

 beach must have been elevated, whilst a third shows it again sub- 

 mersed. 



