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II. — The Plant Remains in the Scottish Peat Mosses. By Francis J. Lewis, F.L.S., 

 Lecturer in Geographical Botany, University of Liverpool. Communicated by 

 Professor Geikie, LL.D., D.C.L., F.R.S. (With Four Plates.) 



PART III. 

 The Scottish Highlands and the Shetland Islands. 



(MS. received June 25, 1907. Read July 8, 1907. Issued separately November 18, 1907.) 



CONTENTS. 



Introduction 



Brief review of the work in Scotland . 



Method of field work 



The areas investigated — 



1. Valley deposits in the Highlands . 



2. Upland deposits in the Highlands 



3. The Outer Hebrides 



4. The Shetland Islands 



Previous work on Pleistocene plant deposits in 



Britain ........ 



PAGE 



33 

 34 

 35 



35 



41 

 45 

 49 



56 



Relation of the peat strata to other deposits in 



Britain 57 



The Pleistocene plant deposits of the Continent . 58 

 The geographical distribution of the successive 



strata 59 



The relation of the strata to the glacial succes- 

 sion 66 



Summary ........ 68 



List of References 69 



Explanation of Plates 69 



During 1904 and 1905 the author investigated the plant remains of the peat deposits 

 in certain areas of the Southern Uplands and the Highlands. The present paper deals 

 with similar work over large peat-covered areas in the E. and N. W. Highlands, Shetland 

 Islands, and the Outer Hebrides. 



Perhaps the most interesting feature found in the course of the work is the evidence 

 of constant change in the character of the vegetation which has successively covered 

 the peat areas of Scotland. Many areas in different parts of the country have been 

 examined in order to ascertain if this succession can be accounted for by local changes 

 in physical conditions, or whether it represents stages in a long cycle of secular changes 

 in climate, and consequent plant migrations. 



If the successive changes jn vegetation are constant over large areas in different 

 parts of the country, some of the main facts for a distributional history of the British 

 flora are available. 



The scope of such an inquiry is limited by the comparatively small flora characteristic 

 of peat, but, on the other hand, the peat deposits possess certain advantages, for the strata 

 are laid down in a regular series, and thus correlation of the strata in one district with 

 those in another does not usually present any serious difficulty. 



As all the peat deposits are stratified, it becomes a matter of interest to examine the 



plant remains contained in the several strata. The search might be expected to yield 

 TRANS. ROY. SOC. EDIN., VOL. XL VI. PART I. (NO. 2). 5 



