BRITISH POSTGLACIAL &> RECENT DEPOSITS. 425 



" formed of trees about a foot in thickness, having branches half 

 this thickness crossing them, and brushwood covering the whole." 

 At the time this " road " was made Kincardine Moss was " an 

 unstable and boggy waste," as it continued to be down to a 

 recent date, when it was drained. 1 There can be no doubt, 

 however, that the Eomans did destroy some portion of the 

 ancient woods. I very much doubt, however, whether Scotland 

 was so well clothed with forest during the Eoman occupation 

 as some chroniclers would have us suppose. It seems to me 

 that the known existence of large trees buried under peat has 

 had much to do with the traditions of a well- wooded Scotland 

 in historical times. 2 



Some account has been given above of the terraces of alluvial 

 detritus which are so common a feature in the river valleys of 

 Scotland. Besides these there occur numerous sheets of loam, 

 clay, sand, marl, etc., which mark the sites of ancient lakes, 

 some of which must have been silted up and grown over at a 

 very early period, while others have been drained artificially in 

 recent times. In the lowlands of Scotland they are specially 

 abundant, and many were lakes at so late a date as 1654, for 

 they are shown as such in Bleau's Atlas. The deep drains 

 which have been cut across these alluvial flats frequently show 

 the following succession of beds : — 



1. Peat, sometimes containing an upper forest-bed. 



2. Ancient forest of oaks and other trees. 



3. Loam and marl, with lacustrine shells and remains of 



red deer, etc. 



4. Boulder-clay. 



From this succession we may infer, first, that a lake existed 

 for a considerable time so as to allow of the accumulation of the 

 marl, which now and again may reach a thickness of several 

 feet. The marl in many cases would appear to be due to the 

 vital action of Charm and freshwater molluscs, such as Limncea 



1 "Wilson's Prehistoric Annals of Scotland, 2d edit., vol. i. p. 52. 



2 See Trans. Royal Soc. Edin., 'vol. xxiv. p. 368, et sea. ; and Great Ice Age, 

 chap. xxvi. 



