1849.] AUSTEN ON THE VALLEY OF THE ENGLISH CHANNEL. 93 



takes its course, alluvia are to he found at elevations such as tlie ex" 

 isting streams never attain. At that time I was disposed to refer 

 these former broad river-courses to the period of the so-called raised 

 beaches. I have recently had an opportunity of re-examining some 

 of these valleys, and of looking at like phsenomena in other places, 

 and I now feel satisfied that the two classes of accumulation are per- 

 fectly distinct as to time. 



The volume of the rivers of a district depends directly on the 

 amount of moisture precipitated over it, and this depends on its ele- 

 vation above the sea ; so that to depress any given area will not tend 

 to increase its rivers. There are other olDJections apart from this 

 general one ; if we take any river-course opening out into the English 

 Channel, such as that of the Dart, and suppose a depression of the 

 land to take place of 1 00 feet, we should obtain a great extension of 

 the estuary portion of such river, which portion would be permanently 

 characterized by its cliifs and accumulations. This new water-level, 

 though it might account for estuary beds and shells at a higher level 

 than before, would have no influence on the upper portions of the 

 streams flowing down into such estuary, so as to augment their vo- 

 lume. In the valley of the Dart, however (as well as in all the others), 

 there is no indication whatever of any estuary beds at higher levels 

 than the present ones ; but the ancient alluvia, which conform to the 

 dimensions of the valley, and are distinguishable from the recent by 

 their coarse torrential character, as well as breadth, can be traced by 

 Holne Bridge and Staverton, till they pass down beneath the accumu- 

 lations of the present estuary. These observations apply to every river 

 of the West of England ; none of them show estuary beds above the 

 present water-level, but their upper portions show alluvia which are. 



The conditions which alone will account for these appearances are 

 obvious — the country, instead of having been placed at a lower level 

 at the period of these broad alluvia, had a much greater elevation 

 above the sea, and when the sea did not reach such portions of these 

 valleys as it does now. This condition is not local, but is applicable 

 to every considerable river-course in the island, along every one of 

 which we can find indications of the larger dimensions of the former 

 rivers. The Thames and the Severn are striking examples. 



That the whole area of the English Channel had at one time a 

 higher level, is directly proved by the numerous instances along its 

 shores where old forest ground passes beneath the present sea-bed : 

 these are marked on the map. It seems to be constantly assumed 

 that the original position of these wooded tracts was close to the coast- 

 line, or at the sea-level ; but for such a supposition there seem to be 

 no grounds whatever. Proximity to the sea is generally unfavourable 

 to the growth of timber. If we take the whole line of the coasts of 

 the Channel on either side, we shall not find any wooded tracts coming 

 down to it, or even single trees of any magnitude ; yet in many in- 

 stances the trees of these submerged lands had attained a very great 

 size. Again, the trees which have been identified from these sub- 

 merged woods, such as the elm, oak, chestnut, hazel, are none of 

 them such as have their usual habitats along the sea-board. But per- 



