678 JAMES GEIKIE 



of Liverpool, has during the last few years subjected our peat- 

 mosses to a careful examination, with results that are sufficiently 

 striking. His work is not yet completed, but he has already studied 

 the peat of our Southern Uplands, and carried on similar researches 

 throughout wide areas in the Highlands, The data now collected 

 have convinced him that a definite succession of plants everywhere 

 characterizes the Scottish peat : and he confirms the view of alter- 

 nating climatic conditions which I formulated forty years ago. 



The Southern Uplands is the general term apphed to that belt 

 of hilly and mountainous country which extends from the coasts of 

 South Ayrshire and Wigtonshire to the high grounds that terminate 

 on the east coast between the valleys of the Tweed and the Tyne. 

 Throughout this broad tract peat-mosses abound — large areas of 

 the higher grounds being of a dominantly moorland character. 

 Nowhere are the peat-mosses better developed than in the moun- 

 tainous district of Merrick, in Galloway, and in the lofty region 

 in which the river Tweed takes its rise. To these two typical areas 

 Mr. Lewis has devoted special attention, and the results of his obser- 

 vations have already been published.^ In both districts the peat- 

 mosses bear the same relation to the glacial and fiuvio-glacial deposits 

 — they everywhere overHe the moraines and morainic detritus of 

 our "District Ice- Sheets and Mountain- Valley Glaciers." 



The first well-marked zone at the base of the peat in the Southern 

 Uplands is a solid layer of the remains of white birch (Betula alba), 

 mixed with such plants as heather (Calluna vulgaris), and willow 

 (Salix re pens). Mr. Lewis thinks it is hardly possible that this 

 zone represents the primitive vegetation which covered the Uplands 

 immediately after the disappearance of glacial conditions. The 

 first- comers would naturally be arctic types, the preservation of 

 which, however, would entirely depend upon climatic and local 

 conditions. In the Merrick District Mr. Lewis observed that in 

 many places a thin layer of peat occurred immediately underneath 

 the birch zone, but unfortunately the material was in too decom- 

 posed a condition to allow of the identification of any particular 



I "The Plant Remains in the Scottish Peat-Mosses; Part I: The Scottish 

 Southern Uplands," Transactions of the Royal Society of Edi7iburgh, Vol. XL,I (igo^), 

 p. 699. 



