12 



deposits of vegetation in lakes or estuaries is strengthened by the circumstance 

 that a bed of wliitish mud or shale is found under every one of the seams in South 

 Wales, a vast coal field, the limestone edge of which was visible from that spot. 

 This white mud or shale is found to be similar in its nature to the deposit of mud 

 which was found at the bottom of lakes and pools when they were dried up. The 

 inference is that every one of the many coal seams of South Wales was formed in 

 a similar position ; that the mass was then submerged, and again becoming 

 dry land, was elevated, and became the site of a fresh deposit of vegetation. 

 In many cases trees were found erect in the coal beds, a fact which showed that 

 they had been buried on the spot where they had grown. The position of parts 

 of the carboniferous strata on the summit of the Black Mountains, and on other 

 elevated spots, rendered it probable that the whole surface of Herefordshire was 

 once covered with carboniferous strata to an immense thickness, which were 

 broken up by convulsions of the earth, and swept away by the action of water. 

 This process of degradation by water is still going on : the Wye is const?intly 

 carrying down into the Bristol Channel, and thus to the ocean, portions of the lime- 

 stone and other rooks through which it passes ; and the mass is accumulating in 

 the Atlantic, above the remains of similar rocks, which have been thus carried 

 away in past ages. 



Leaving the coal pits of Christchurch, the party retraced their steps to 

 Symonds Yat, and, descending the slope of the promontory, reached the very 

 striking outcrop of the Conglomerate, which lies between the Mountain Lime- 

 stone and the Old Red Sandstone. This formation (Mr. Strickland explained) 

 was composed of rounded fragments of quartz, greenstone, jasper, &c., which had 

 been deposited in the mud of a turbid ocean. The quartz is what is called vein 

 quartz, and many of the pebbles contain with it portions of the rock in which the 

 quartz vein was formed. In some cases this is a chlorite schist. An interesting 

 circumstance was here noticed : a longitudinal fissure in the rock, 20 feet in 

 length, was partly occupied by one of the roots of an oak, which had grown down 

 in search of moisture ; and partly by a stalagmite, or deposit of carbonate of lime 

 from water. Mr. Strickland explained that the formation of stalagmite was 

 identical with the process called " petrification." 



The party now returned across the Wye to Whitchurch, on their way to the 

 inn, noticing a curious instance of the power of vegetation to accommodate itself- 

 to altered circumstances. A poplar tree having fallen or been blown across a 

 small pool, the branches continue to grow along the upper side of it ; but instead 

 of preserving the curved direction towards the summit of the tree, which char- 

 acterises the species, the branches all shoot straight upwards, and therefore at 

 right angles to the stem. 



Throughout the pleasant ramble, some of the party devoted their attention 

 in part to the botany of the district. The equally rare and beautiful Bee-orchis ; 

 the Small St. John's Wort ( Hypericum pulchruin), the Canterbury Bell (Campan- 

 ula latifolia), the Scrophularia nodosa, and other more common plants, were 

 found growing abundantly. As, however, the presence of the distinguished 



