44 Proceedings. 
Above the forest-beds are clays with lignite. In these clays 
Salix polaris and an arctic moss have been found, and also 
Betula nana. 
Above these clays is boulder-clay containing no fossil remains. 
Above the boulder-clay are freshwater clays containing 
Betula nana, Salix polaris, S. reticulata, S. herbacea, and Dryas 
octopetala. All these are arctic species, and no plants other 
than arctic have been found. The same plants occur in the 
clays under the bogs in Denmark. 
In the Danish bogs is a bottom layer containing Populus 
tremula. The next layer contains Pinus sylvestris. Then 
comes Quercus sessiliflura, then Quercus pedunculata; and in 
the uppermost layer of the bogs Alnus glutinosus. 
On the solid ground above the bogs Beech is the prevailing 
tree. 
The calcareous tuff-deposits of Denmark contain numerous 
prints of shrubs and trees. 
In the lower deposits Dryas octopetala occurs with Hippophaé 
rhamnoides. 
In higher deposits occur shrubs, Pinus sylvestris, Water-lilies, 
&e. Higher still is Oak but no Firs, and higher is Alder, but 
no Beech or Hornbeam, which are now common in Denmark. 
Spruce Fir is found fossilized in no stratum above the 
boulder-clay in England or Denmark. It has most likely 
entered Norway from the east by way of Finland. 
The occurrence of layers in the bogs points to the alternation 
of wet and dry periods. During the wet periods bog formed; 
during the dry periods trees could grow. 
These observations tend to show the immensity of time that 
has elapsed. 
In Norway the lower bogs have but one layer of peat; the 
next have two layers; and those at still higher elevation have 
three layers. Most probably the lower were below sea-level 
when the upper ones were formed, and the land has risen more 
recently. 
The Scotch Fir is not now wild in Denmark, and does not 
thrive in most parts of Denmark when planted, nor do arctic 
