( 793 ) 



XXVI. — The Plant Remains in the Scottish Peat Mosses. By Francis J. Lewis, 

 M.Sc, F. L.S., Lecturer in Geographical Botany, University of Liverpool. Com- 

 municated by J. Horne, LL.D., F.R.S. (With Five Plates.) 



PART IV. 



The Scottish Highlands and Shetland, with an Appendix on the 



Icelandic Peat Deposits. 



(MS. received June 2, 1910. Read July 18, 1910. Issued separately March 31, 1911.) 



CONTENTS. 



PAGE 



Introduction .... .... 793 



Technique 794 



The areas investigated — 



1. The Shetland Islands 795 



(a) Walls district on the west of Shetland 



Mainland 796 



(b) Weisdale and Voe, Shetland Mainland 803 



(c) The Island of Foula . . . .805 

 The First Arctic Stratum in Shetland . . 807 

 The Lower Forest Stratum in Shetland . 808 

 The Second Arctic Stratum in Shetland . 809 



2. Poole we, Ross-shire 809 



3. East Sutherlandshire — Rhilochan . . .811 



4. Peat on the Raised Beaches at Ardgour and 



Banavie, Ross-shire and Argyllshire . 813 



PAGE 



815 

 816 



Stratigraphy of Peat and the Forest Beds 



(a) The Lower Forest in Shetland 



(6) The Lower and the Upper Forest in 



Kirkcudbrightshire . . . .817 



(c) The Upper Forest in Inverness-shire . 817 

 Causes of the existence and of the disappearance 



of the Lower and of the Upper Forest . . 820 



Summary 826 



Appendix A. Observations on the Peat Deposits of 



1 Iceland 827 



Appendix B. Mosses from Peat Deposits, by H. N. 



Dixon .829 



List of References 831 



Explanation of Plates 832 



The present paper deals with further investigations into the structure, the stratifica- 

 tion, and the plant remains of peat deposits, carried on in various districts during 1907, 

 1908, and 1909. 



The objects of the research, stated briefly, are to determine, as far as the state of 

 preservation of the material permits, the history of the flora on peat-covered areas since 

 their formation during the later stages of the glacial period. This really resolves 

 itself into a research dealing with the changes in distribution undergone in post-glacial 

 times by part of the British flora. Considering the great extent of peat areas in Britain 

 and the laborious work of detailed examination of stratification in the field and peat 

 material in the laboratory, it is obvious that many years must elapse before any 

 complete account can be given of the history of such deposits in the British Isles. 



So much attention has been given during late years to this subject in Sweden, 

 Denmark, Norway, Germany, and Switzerland that investigations on peat mosses in 

 Britain are needed, not only for the object of working out the history of events in this 

 country, but for comparison of these events with those on the Continent. 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART IV. (NO. 26). 116 



