268 The Scottish Naturalist. 



November in that year the river was from 16 to 18 feet deep in 

 this curve, now it is filled up in some parts higher than the 

 ordinary level of the river. This brings us to another considera- 

 tion, viz. : that of fluviatile deposition. This particular dead- 

 water has filled at the rate of nearly one foot per annum. The 

 history of all dead-waters is doubtless that of D. As soon as the 

 current leaves them they begin to fill up by the sediment from 

 the water that is poured into them during every "spate." That 

 all dead-waters fill as rapidly as did D I am not prepared to 

 assert. C is filling very slowly, but that is owing to artificial 

 obstruction to the free ingress of the water. There are other 

 remains of ancient dead-waters on the south side of the river 

 marked on the map by double dotted lines. 



The restoration of the land — not the mere building up of 

 patches of pebbles and sand, but the rearing of wide acres of 

 arable soil, of considerable thickness and void of pebbles, must 

 now be considered. It has been seen how the pebble beds 

 accummulate, it now remains to see how the "loam" is placed 

 above them. To understand this one must again turn to the 

 river, for 



" Men may come, and men may go, 

 But it goes on for ever." 



I see the river rising 8, i o, 12 feet above its usual level. The 

 pebble beds have long been hid, and the water is out upon the 

 fields. The flood is angry and powerful — full of the debris of 

 the torn-up beds, and of the yielding banks, and clouded is its 

 usual lucid face. But it must yield as surely as it came ; and 

 foot by foot the greensward shows itself again, till all is peace — 

 the river mild and clear. It has, however, not gone without 

 leaving its footprints behind. Is there not evidence of this 

 wherever the water has been? Has not the thickness of the 

 soil been added to? Is not the grass in many places partially, and 

 in some indeed quite, buried? Undoubtedly that is the case. 

 Then it can easily be seen that if this process be repeated a 

 sufficient number of times, any thickness of fine light soil can 

 be obtained. On the pebble-beds a very ramified grass takes 

 root here and there, and each clump becomes a shelter for 

 straying sand, and apparently increases in vigour in proportion 

 to the quantity of sand it can accumulate. This process aids 

 the heightening of the bed very materially, for the clumps 

 become quite large — as large as sheep, and protect long 

 diminishing lines of sand behind them. These soon 



