NATURAL HISTORY OF CREATION. 71 



of the present surface, iisnally seen in a lowly and 

 creeping form in temperate latitudes, but presenting- 

 species which rise to a greater magnitude within the 

 tropics. Many specimens of this family are found in 

 the coal beds ; it is thought they have contributed more 

 to the substance of the coal than any other family. 

 But, like the ferns and equisetaceas, they rise to a pro- 

 digious magnitude. The lepidodendra (so the fossil 

 genus is called) have probably been from sixty-five to 

 eighty feet in height, having at their base a diameter of 

 about three feet, while their leaves measured twenty 

 inches in length. In the forests of the coal era, the 

 lepidodendra would enjoy the rank of firs in our forests, 

 affording shade to the only less stately ferns and cala- 

 mites. The internal structure of the stem, and the 

 character of the seed-vessels, show them to have been a 

 link between single-lobed and double-lobed plants, a fact 

 worthy of note, as it favours the idea that, in vegetable, 

 as well as aninial creation, a progress has been observed, 

 in conformity with advancing conditions. It is also 

 curious to find a missing link of so much importance in 

 a genus of plants which has long ceased to have a living 

 place upon earth. 



The other leading plants of the coal era are without 

 representatives on the present surface, and their cha- 

 racters are in general less clearly ascertained. Amongst 

 the most remarkable are — the sigUlaria, of which large 

 stems are very abundant, showing that the interior has 

 been soft, and the exterior fluted w^ith separate leaves 

 inserted in vertical rows along the flutings — and the 

 stigmaria, plants apparently calculated to flourish in 

 marshes or pools, having a short, thick, fleshy stem, with 

 a dome-shaped top, from which sprung branches of from 

 twenty to thirty feet long. Amongst monocotyledons 



