210 The Scottish Naturalist. 



Such, then, are the principal geographical and climatic changes 

 to which the geological phenomena of post-glacial and recent 

 accumulations seem to bear witness. The evidence is clear 

 enough so far as it goes ; but you will observe that, after all, the 

 geologist can give only the meagre outlines of a picture. For the 

 details which are wanted to give life and colour to the picture, we 

 must rely upon our zoologists and botanists. It is to them that 

 we look for the further elucidation of this interesting history. 

 Already much has been done, chiefly by foreign naturalists, to 

 extend our knowledge of post-glacial events. 



Professor Blytt, after studying the distribution of the Norwegian 

 flora, had formulated the belief in alternating dry and humid 

 conditions having supervened in post-glacial times. By following 

 out a totally different line of research he was led independently to 

 the same conclusion as myself. And what Blytt has done for 

 Norway, surely our naturalists might achieve for Scotland. 



It is with the hope of inciting some of the workers in this East 

 of Scotland Union to undertake the task that I have ventured to 

 give this rapid and imperfect sketch of post-glacial climatic and 

 geographical changes. If there be any foundation for the views 1 

 have brought before you, it is almost certain that these views will 

 be corroborated and greatly extended by a more complete and 

 detailed knowledge than we yet have of the character and distri- 

 bution of our plants and animals. I have often wondered why 

 our botanists should have so entirely neglected the minute study 

 of our peat-mosses : for I cannot but believe that the history of 

 post-glacial Scotland is in large measure locked up, as it were, in 

 those turbaries. When one knows how much has been done to 

 work out the history of the continental peat-bogs by such observers 

 as Steenstrup in Denmark, Blytt in Norway, Nathorst in Sweden, 

 Grisebach in Germany, and Fliche in France, one cannot but wish 

 that some of our Scottish naturalists would undertake the examina- 

 tion of our own peat-mosses. Surely the task is not too hard. 

 Peat is not composed of extinct species of plants ; the animal 

 remains now and again associated with them are all, (with the 

 exception of one or two large vertebrates), living forms, al- 

 though some of the species both of plants and animals, may no 

 longer live in Britain. In dealing with the constituents of our 

 peat, therefore, one has to do not with extinct but with existing 

 forms. And surely comparisons between the organic remains of 



