88 PICTURESQUE SKETCHES 



world where vegetation, although even more luxu- 

 riant, belongs to a different type. 



And there is, after all, nothing improbable in the 

 notion, that, at the period of the deposit of the coal- 

 measures, the northern hemisphere in our latitudes 

 was for the most part occupied by a great ocean, stud- 

 ded over with numerous islands, some of larger, some 

 of smaller size ; open water reaching from this archi- 

 pelago quite to the arctic circle. Innumerable islands 

 and reefs may have been there planted and destroyed, 

 while some few, undergoing depression at a slow rate, 

 became before their final disappearance the receptacle 

 of those sandy and muddy banks among which the 

 vegetable matter was embedded. Numerous inlets 

 may have indented the coast line of the larger islands, 

 and have received into them rivers or mountain 

 streams, loaded with the fragments of trees and other 

 vegetables brought down during the rainy season. 



The whole of the interior of the islands may have 

 been clothed with thick forest, the dark verdure of 

 which would only be interrupted by the bright green 

 of the swamps in the hollows, or the brown tint of 

 the fern covering some districts near the coasts. The 

 forest would have been formed by a mixture of seve- 

 ral different trees. We should see there, for instance, 

 the lofty and widely-spreading Lepidodendron, its deli- 

 cate, feathery, arid moss-like fronds clothing in rich 

 luxuriance branches and stems, which are built up, 

 like the trunk of the tree-fern, by successive leaf- 

 stalks that have one after another dropped away, 

 giving by their decay additional height to the stem, 

 which might at length be mistaken for that of a 

 gigantic pine. 



