AND PEAT MOSSES OF SCOTLAND. 377 



to spread itself. In the lakes and pools of the country, Sphagnum and other 

 aquatics had luxuriated from an early period, covering the surface of the water 

 with an unstable crust, which often-times gave way beneath the weight of large 

 quadrupeds, such as the Irish deer. Many old lake hollows, long since filled up 

 with peat, teem with the relics of this and other animals of the period ; but the 

 process of filling up these ancient basins is still in many cases incomplete. Flow- 

 mosses and quaking bogs have yet to pass into the condition of solid peat. With 

 the increasing humidity of the atmosphere, bog mosses were no longer to be 

 restricted to lakes and pools. As the forest trees decayed along the exposed sea- 

 coasts, the mosses crept over their prostrate trunks, and, spreading inland, began 

 to invest those trees that had not yet succumbed to the inclemency of the cli- 

 mate. On the moist hill-tops the same increase of mosses went on, as throughout 

 the country generally there were doubtless many other spots where the same 

 conditions were followed by like effects. The stems, invested by the wet mosses 

 in their upward growth, gradually rotted away, and were thus ready to yield to 

 the first strong wind. So the destruction proceeded — the mosses ever widening 

 their area, creeping outwards and downwards from the misty hills, and inland 

 from the storm-swept coasts. 



This mode of accounting for the decay of the trees seems to be warranted by 

 the state in which they have been preserved. Rennie has remarked, and the 

 truth of the statement is easily confirmed, that the " upper side or surface of 

 trees found in moss is uniformly most consumed ; an oak may be often seen 

 where the upper half is so consumed that only the semi-diameter of the tree 

 remains." He subsequently says that when the bark has been preserved (which 

 is not often), it usually adheres to the under portion of the prostrate stems. Thus, 

 at the time these trees fell, a certain thickness of mosses had formed, which 

 received and protected from decay the under portions of the stems, but the upper 

 semi-diameters had rotted from exposure before the advancing mosses could 

 reach them. Dr Rennie, however, was of opinion that this partial preservation of 

 the buried trees " is a proof that the tree when it fell on the spot had been half- 

 immersed in the mass of ruins, and that half," he adds, " has been thereby pre- 

 served entire." Again he says : " Some trees in every forest decay through age ; 

 it is probable whole forests may have suffered this fate, especially where a subsoil 

 of moss had been formed around the roots of the trees during the period of their 

 growth. Chilled by this means, not only the bark but the white wood would 

 crumble away before the trees were finally overthrown." By the expression 

 subsoil of moss, Dr Rennie means the vegetable mould resulting from the decom- 

 position of fallen leaves, fir cones, and branches, which in another place he shows 

 us might oftentimes form a considerable thickness of peat. Now, it is quite true 

 that at the bottom of many peat mosses we have a certain thickness of what has 

 been called stratified peat — the vegetable mould that collected underneath the 



