80 
TIIE FERN FORESTS OF 
series of gradation in the Yegetable Kingdom, as 
well as the Animal Kingdom, is the same, whether 
founded upon succession in time or upon com- 
parative structural rank. 
Some attempt has been made to reproduce un- 
der an artistic form the aspect of the world in 
the different geological ages, and to present in 
single connected pictures the animal and vege- 
table world of each period. Professor P. Unger, 
of Vienna, has prepared a collection of fourteen 
such sketches, entitled, “ Tableaux Physiono- 
miques de la V6g6tation des Diverses Periodes 
du Monde Primitif.” 
First, we have the Devonian shores, with spread- 
ing fields of sea-weed and numbers of the club- 
shaped Algse of gigantic size. He has ventured, 
also, to represent a few trees, with scanty foliage ; 
but I believe their existence at so early a period 
to be very problematical. 
Next comes the Carboniferous forest, with still 
pools of water lying between the Fern-trees, 
which, much as they affect damp, swampy 
grounds, seem scarcely able to find foothold on 
the dripping earth. Their trunks, as well as 
those of the Club-Moss trees which make the 
foreground of the picture, stand up free from 
any branches for many feet above the ground, 
giving one a glimpse between them into the dim 
recesses of this quiet, watery wood, where the 
