336 



ISLAND LIFE 



PAET II 



On the coast of theBristol Channel similar deposits occur, 

 as well as along much of the coast of Wales and in Holy- 

 head Harbour. It is believed by geologists that the whole 

 Bristol Channel was, at a comparatively recent period, an 

 extensive plain, through which flowed the Eiver Severn ; 

 for in addition to the evidence of submerged forests there 

 are on the coast of Glamorganshire numerous caves and 

 fissures in the face of high sea cliffs, in one of which no 

 less than a thousand antlers of the reindeer were found, 

 the remains of animals which had been devoured there by 

 bears and hyaenas ; facts which can only be explained by 

 the existence of some extent of dry land stretching sea- 

 ward from the present cliffs, but since submerged and 

 washed away. This plain may have continued down to 

 very recent times, since the whole of the Bristol Channel 

 to beyond Lundy Island is under twenty-five fathoms deep. 

 In the east of England we have a similar forest-bed at 

 Cromer in Norfolk ; and in the north of Holland an old 

 land surface has been found fifty-six feet below high-water 

 mark. 



Buried River Channels. — Still more remarkable are the 

 buried river channels which have been traced on many 

 parts of our coasts. In order to facilitate the study of the 

 glacial deposits of Scotland, Dr. James Croll obtained the 

 details of about 250 bores put down in all parts of the 

 mining districts of Scotland for the purpose of discovering 

 minerals.^ These revealed the interesting fact that there 

 are ancient valleys and river channels at depths of from 

 100 to 260 feet below the present sea-level. These old 

 rivers sometimes run in quite different directions from the 

 present lines of drainage, connecting what are now 

 distinct valleys ; and they are so completely filled up and 

 hidden by boulder clay, drift, and sands, that there is no 

 indication of their presence on the surface, which often 

 consists of mounds or low hills more than 100 feet high. 

 One of these old valleys connects the Clyde near Dum- 

 barton with the Forth at Grangemouth, and appears to 

 have contained two streams flowing in opposite directions 

 from a watershed about midway at Kilsith. At Grange- 

 ^ Transactions of the Edinburgh Geological Society, Vol. I. p. 330. 



