MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 



found upon Mr L YELL'S authority, in support of the opinion which I have just ex- 

 pressed, though advocated by himself at a former period. But it is a circumstance 

 in favour of that opinion, that it was the conclusion to which he came, after ex- 

 amining the kaims of Sweden. The following passage occurs in his Paper before 

 referred to : " The occurrence of layers of marl containing littoral shells, as above 

 described, in the midst of a stratified ridge of sand and gravel, is opposed to the 

 theory of those geologists, who refer the formation of such ridges to a violent flood 

 or debacle rushing from the north. The perfect preservation of the shells at Up- 

 sala, and the repeated succession of thin alternating layers of gravel, sand, and 

 loam, which are seen almost everywhere, imply a gradual, and at times a very 

 tranquil, deposition of transported matter. If I am asked for a more probable 

 hypothesis in the room of that to which I.object, I may state that these ridges ap- 

 pear to me to be ancient banks of sand and shingle, which have been thrown down 

 at the bottom of the Gulf of Bothnia, in lines parallel to the ancient coast during 

 the successive rise of the laud ; or in other words, during the gradual conversion 

 of part of the gulf into land. I conceive that they may have been formed in those 

 tracts, where a marine current, flowing as now, during the spring when the ice 

 and snow melt, from north to south, came in contact with flooded rivers rushing 

 from the continent, or from the west, charged with gravel, sand, and mud. Ac- 

 cording to this view, these large Swedish ridges may be compared to smaller 

 banks known to have been formed within the last five or six centuries on the 

 eastern coast of England, at points where a prevailing marine current from the 

 north meets rivers descending from the interior, or from the east." 



But whilst I adduce, in support of my view, the opinion of Mr LYELL, at least 

 as entertained in 1834, I know that its soundness must be tried, not by authori- 

 ties of that kind, but by an accurate survey of facts. I merely found on his opi- 

 nion, in order to bespeak, on behalf of the foregoing views, an attentive considera- 

 tion. 



(3.) But farther, and independently of the operation of submarine currents 

 in forming elongated banks of sand and gravel, it remains to be considered what 

 effects would be produced on the bottom of the ocean, on becoming exposed to 

 atmospheric and other natural influences. 



That the rain itself must act powerfully in washing away and carrying off 

 sand and small gravel, cannot be doubted ; and this agent, trifling as it is, appears 

 to me quite sufficient to have produced the almost innumerable mounds and knolls 

 which, as already remarked, are to be seen near Palinsburn, Gala House, and 

 Lamberton. It is impossible, indeed, to doubt that a thick and extensive bed of 

 sand and shingle would, by this cause, after the lapse of time, be cut up into sec- 

 tions of various dimensions ; and when the channels or gutters thus formed reach- 

 ed any considerable depth, the loose materials would begin to be undermined, and 

 separate mounds and banks would be speedily formed. 



It is evident that no limit can be prescribed to the variety of forms which the 



