I] INTRODUCTORY 13 



accompanying photograph (Fig. 1), taken by my friend 

 Mr A. G. Tansley, in the Black Wood of Rannoch in 

 north-west Perthshire, shows a few trees of Plnus 

 si/lvestris growing in their native soil : the form of 

 the older tree {A) suggests comparison with that of 

 a well-grown beech such as we are familiar with 

 in English plantations. This spreading dome-shaped 

 habit seems to be a peculiarity of the Highland tree, 

 and is one of the characters which have led some 

 botanists to regard it as a variety (Pinns sylvestris 

 var. scotica) of the ordinary Scots pine. Though it 

 is doubtful if any relics of primeval pine woods are 

 left in England, abundant evidence of the former 

 existence of the Scots pine is afforded by the sub- 

 merged forests exposed at low-tide on many parts of 

 the English and Welsh coasts and at the base of 

 some of the English peat moors. During the con- 

 struction of the Barry docks on the north coast of 

 the Bristol Channel a few years ago, the exposed 

 sections of peat and forest beds were investigated by 

 Dr Strahan and by Mr Clement Reid. There is 

 evidence of a subsidence of the land to an extent of 

 55 feet since the formation of the lower peat-beds 

 containing oak, hazel, willow, and other trees. The 

 pine, unknown in Wales during the historic period, 

 was recognised in the Barry cutting. The occurrence 

 of a polished flint implement assigns a date to the 

 uppermost portion of this old land-surface do). 



