6 PRESIDENT'S ADDRESS. 



The changes are more clearly shewn in the Scandinavian 

 and Danish peat-beds, by which are defined the nature of the 

 different forests which grew up, perished, and succeeded each other, 

 suited to the altered conditions of climate. An Arctic flora is found 

 beneath the oldest forests which are chiefly composed of the aspen 

 and birch. The Scotch fir comes next in succession, then the oak, 

 and, lastly, the alder. The beech is now the prevailing tree. It 

 seems clear then that as the Glacial Age was passing away and the 

 climate ameliorated, forest trees grew and flourished. The Scotch 

 firs in the earliest beds are stunted ; their rings of growth are 

 so compact that 70 can be counted in one inch of thickness. In 

 spite of these apparent unfavourable conditions they managed to 

 live for three or four centuries. The beech has supplanted the oak 

 in Denmark, and the forests of which it is composed are reckoned 

 to be the finest in the world. The flora which preceded the aspen 

 and the fir was decidedly Arctic, such as Dryas odopetala, Salix 

 polaris, S. herbacea, and S. reticulata, Betula nana, Oxyria digyna, 

 and one bird a Swift Apus glacialis, which is not uncommon now 

 in the Spitzbergen lakes, but is not met with farther south than the 

 Douvre Mountains. The Hippophae rhamnoides, which grew side 

 by side at that remote period with Dryas octopetala, has lost its 

 Arctic habits and even grows at sea level in temperate regions. I 

 have found it near Grenoble, on the dry portions of the bed of the 

 river Drac. It has taken a firm hold in the green walks of Lord 

 Ilchester's lovely gardens at Abbotsbury Castle. It is noticeable 

 that the Spruce-fir was indigenous in England before the Ice Age, 

 when it migrated southward never to return as a native. The 

 Grass of Parnassus and the Stag-moss are among the few 

 representatives of the northern flora in Dorsetshire. 



The tufaceous beds of France, Italy, and Germany have thrown 

 much light upon the migration of plants caused by climatal changes 

 and the influence of man. Their origin is due to a calcareous 

 precipitate, which encrusted every object with which it came in 

 contact, giving it the appearance of having been turned into 

 stone, leaving impressions of the shape and structure of mosses, 



