170 ON THE REVOLUTIONS 



On my return from the Alps, looking for traces of the same 

 agents in this country, I found them in abundance, particu- 

 larly in the neighbourhood of Edinburgh ; and the circumstan- 

 ces of this sort which I have met with, both on a large scale 

 and in detail, seem to afford more precise information as to 

 these events than has hitherto been furnished by tlie alpine 

 phenomena. 



In order to acquire principles upon which these observations 

 may be made to advantage, and by which the truth or false- 

 hood of the systems to which they lead may be brought to a 

 certain test, it is of importance to examine the results of simi- 

 lar actions, in such analogous cases as He in all respects within 

 reach of observation. If a torrent, like that which is supposed 

 to have inundated the Alps, had flowed over this country, it 

 must have left behind it traces of various sorts, resembling in 

 some degree those that occur in the course of any common 

 river which has recently overflowed its banks. Thus in both 

 cases, sand and mud, and loose stones, must have been transport- 

 ed and deposited ; and fixed objects must have been overwhelm- 

 ed and. abraded, by the action of the water and of these mo- 

 ving bodies : The relation of the stream to these objects, either 

 met or transported, is very different, it is true, in the two 

 cases ; but a sufficient agreement exists between them to guide 

 us on the present occasion. 



It is an undoubted truth, that where an obstacle occurs in 

 the course of a fluid, which is in the act of transporting and 

 depositing heavy substances, the deposition in the neighbour- 

 hood of that obstacle undergoes considerable modification. 

 The theory of these modifications would be difficult to deter- 

 mine ; but their effects may easily be traced, by observation in 

 the bed of any stream after a flood, or in the drifting of snow, 

 fallen during a high wind, or which is in the act of falling. 



Where 



