524 Correspondence — Col. George Greenwood. 



us of a raised beach, on Portland " thirty or forty feet above the sea." 

 Is not this proof positive of the correctness of my theory? Did 

 Portland rise thirty or forty feet and the isthmus remain stationary ? 

 This junction with the land made Portland a groin protruding at 

 right angles with the line of coast ; and I have headed a passage 

 (page 119 "Eain and Rivers") "Portland is a natural groin which 

 catches the Chesil beach." I have also said that to any one con- 

 versant with the laws of the groin the mysteries of the Chesil beach 

 vanish. Mr. Whitaker adopts the term " natural groyne" as his 

 own. He also adopts the theory as his own, and says of it " that of 

 course all must agree" to it. I have never happened to see Portland 

 called a " natural groin ;" nor have I seen the phenomena of the 

 Chesil beach explained as those of a beach collected and formed by 

 a groin. If Mr. Whitaker has, perhaps he will tell us where and by 

 whom this has been published. Be this as it may, I would wish to 

 say a word as to the heaping of the beach which is formed by the 

 "natural groin." Mr. Whitaker avoids the question; but he 

 mentions " the set of the current" from west to east three times. 

 The shingle he thinks is carried by this current, since, page 435, the 

 shingle is " stopped in its easterly course," and in page 436 he 

 seems to form the shingle beach by " the general set of the current." 

 Lyell, as quoted by Mr. Whitaker, attributes the heaping to " meet- 

 ing of tides," " a great eddy," " the tidal wave," and " the set of the 

 tide in the narrow channel." While Herschel (Physical Geography, 

 second edition, page 91) makes "tide currents" deposit "the great 

 shingle drift of Dungeness Point and the Chesil Bank." 



Let us, for argument, grant Mr. Whitaker's assumed current from 

 west to east along our south coast, and let this current be of force 

 sufficient to drive pebbles of the size of those at the Portland end of 

 the Chesil beach, they would at least travel along the bottom of the 

 current. But even if they floated on the top of the current how 

 could they get to the toj) of the beach which is forty-two feet above 

 the level of the water ? So if Lyell's and Herschel's tide had 

 " eddied" here, it must have flowed as high as the top of the beach, 

 and even then it must have carried the pebbles on its surface to 

 have placed them where they are. These philosophers would be the 

 first to remind us of the rule that water can only find one level, and 

 that it cannot rise above its source ; and this rule entirely precludes 

 the possibility of the beach being heaped by tides or currents. But 

 rules are apt to have exceptions, and the exception here is that when 

 impact is given to water it will rise itself, and it will raise other 

 substances very much higher than its source. In art we see this in 

 the ram which sends water to the top of the house, though the ram 

 and the source of the water may be much lower than the foundation 

 of the house. In nature we see the exception in the effects of the 

 impact given to the wave by the wind. It is then not tides or 

 currents of water, but currents of air giving impact to the waves 

 which have driven the drift to the top of the beach. Drayton gives 

 this vera causa in 1613, " by the south wind raysd." One great 

 law of the sea-shore is, as the wind blows the wave flows, and as 



