Prof. W. Keeping — -Geology of Aberystwyth. 543 



last British stronghold was in the Teifi ; the Bear, whose former 

 presence is proved by such names as Pwl cenawen^ (the cubs' pool) ; 

 and the Otter, which is still hunted in the streams. Trees are 

 however often found well preserved in the peat ; their roots and 

 trunks may always be seen where turf-cutting is going on and 

 sometimes fine trees are found. In the neighbourhood of Tregaron 

 the wood is still used by the carpenters, and portions of trunks are 

 very commonly made into rollers for the fields. 



The best exposure of these prostrate trees is the submerged forest 

 at Berth. Here at low water hundreds of ' stools ' with their roots 

 still fixed in the old soil are seen ; while prostrate trunks and 

 branches are abundantly scattered around. The Oak, Pine, and 

 Beech are most numerous. The soil upon which they grew was 

 very peaty, and was made up to a great extent of reeds, flags, and 

 other vegetable matter matted together. The decomposition of 

 the tissues of these plants gives rise to gases which are now being 

 evolved, and sulphuretted hydrogen especially may be recognized by 

 its fetid odour when the peat is disturbed. Such an old land 

 surface is found throughout Cardigan Bay, extending from below 

 low-water mark to a distance of several miles up the valleys. At 

 Clarach it is occasionally laid bare, and it is nearly always exposed 

 at Tan-y-Bwlch, south of Aberystwyth. 



Beneath the submerged forest at Berth there is a blue clay con- 

 taining marine shells [Scrobicularia piperata and Bissoa pallida), 

 in great profusion. 



In these various deposits on the Berth shore we have the evidence 

 of three changes in the relative level of land and sea. First the 

 old Cambrian rocks were submerged to allow of the deposition of 

 the Scrobicularia clay ; then came an upheaval carrying the latter 

 deposit above high-water mark at least, when the peaty formation 

 was produced in the swampy flat ; and, later on, the beech and pine 

 forests flourished. But again came a depression, which submerged 

 the forest and killed the trees, many of which probably stood long, 

 as bare, leafless skeletons, to be blown down and strewn irregularly 

 along the shore and over the sea-bottom. Only the stools now 

 remain erect ; every tree is prostrate. 



Physical Geography. — The connexion between the physical geo- 

 graphy of a country and its geology must everywhere be most 

 intimate ; and their correlations are generally as easily explained as 

 they are evident. Eocks have their characteristic surface features 

 as well as their characteristic fossils. The rich low country with 

 its many little hills of Tertiary counties, and the grand alternating 

 series of limestone ridges and fertile plains of the Secondary dis- 

 tricts of England, are equally foreign to our neighbourhood. In a 

 country composed of such enduring rocks as prevail in Mid Wales, 

 we are sure to find a more grand and rugged type of scenery, which 

 is only repeated in those areas whose geological structure is similar 

 to it, such as the Lake District of England and parts of Scotland. 

 1 The name of a farm-house near Penllwyn. 



