19-1 On the Causes ivhich have operated 



that the streams, the only visible and conceivable agents 

 for such a work, can have had any share in the excavation 

 and transportation of the niissino materials. He has, how- 

 ever, in his first paper, somewhat ungroundedly admitted, 

 that he had discovered a little of the alluvia carried down 

 by streams and brooks, adding, indeed, as a suitable quali- 

 fication, that they are found so near to the currents as to 

 be naturally enough referred to torrents which hurry through 

 the valleys in ordinary rains. It is very unusual to find 

 Mr. Farey treading on such natural ground as this ; and 

 accordingly, as it' uneasy in his new situation, he instantly 

 couples with these natural torrents, imaginary waterspouts, 

 to assist in carrying down the few basketfuls of alluvial ma- 

 terials which, so unluckily for his own system, he had 

 stuvTibled upon. 



Even allowing Mr. Farcy his own way, in calling this 

 quantity which he has discovered only the thousandth part 

 of the whole, I should still imagine that rain and torrents 

 were quite as efficacious in their power > of transportation at 

 the time the valleys were excavating, as now ; and indeed, 

 they certainly were much more so ; aS the numerous falls 

 which must then have existed, would add greatly to the 

 abrading forces of the currents; and 1 also think, that 

 where we now find a portion, thougli it were only a thou- 

 sandth part, actually lodged where it must have been brought 

 down by the stream, it will be to every one but Mr. Farey 

 himself, a rational conclusion, that the rest, however con- 

 siderable, has travelled ofl' in the same direction ; and that 

 the portion left for our inspection is satisfactorv evidence of 

 the other portion havina; also passed downwards, but be- 

 yond the limits of our further tracing, into the great recep- 

 tacle of all — the ocean. 



But all this cavilling about what has become of the ex- 

 cavated materials, is mere quibbling on a subordinate fact, 

 which, however it may be disposed of, will still leave the 

 great and general question of excavation and its agents un- 

 determined ; and even tliis fact, to any impartial and com- 

 petent person, who will take the trouble of verifying it, 

 will be fojud most substantially as I before represented it. 

 I have never yet iut-pected a flat traversed by the serpentine 

 windings of a stream, without finding every part of the 

 channel cut, in many instances to a considerable depth, 

 through alluvia corresponding with the strata higher up the 

 stream : and not only the whole of the flat, but also up ta 

 certain heights on the surrounding eminences, abounded 

 with the same transported matters. In truth, the universal 



disseininatiuti 



