RELATIVE GEOLOGICAL ANTIQUITY OF TREES. 135 



year, this opinion must be received with some degree of 

 restriction. 



The animals of the Stone-coal period resemble in many 

 respects those of the preceding formations. The crustaceans 

 have, however, improved. In addition to the trilobites, we 

 have the horse-shoe crabs, and other gigantic forms. We also 

 meet with traces of insects and scorpions. These appear to 

 have been the only inhabitants of these swampy forests. No 

 mammalia pastured beneath their shade; no birds warbled 

 forth their melody, or nestled amongst the branches of these 

 leafless, flowerless trees. Trees with true leaves and flowers 

 had not made their appearance. The atmosphere was not yet 

 fitted for their growth. With the exception of the Fir-trees, 

 with their needle-shaped leaves, the vegetation was wholly 

 cryptogamous, and decidedly low in organization. Every 

 Botanist who examines the coal plants is necessarily impelled 

 to this conclusion. There is no denying the evidence of the 

 rocks. 



The Palaeozoic rocks, which contain the fossil remains of 

 the first inhabitants of the earth, extend from the Cambrian 

 formation as far as the Magnesian limestone, which lies above 

 the coal, and, together with the Old Bed Sandstone, constitutes 

 the Zechstein formation of the German geologists. 



A careful examination of the fossil remains found in these 

 rocks, Toy the most distinguished Naturalists, has developed 

 the interesting fact, that the first inhabitants of the world were 

 a few sea-weed zoophytes and shell-fish, and that, throughout 

 the whole of the immense period of time occupied in the 

 formation of these rocks, vegetation did not advance further 

 than the Coniferas or Pine family, the highest rank of the 

 animal creation being a low order of fishes. 



The period immediately succeeding the Stone-coal era was 

 characterized by great volcanic activity: the 'rocks were up- 

 heaved, and storm and annihilation swept over the island- 

 forests of the Stone-coal landscape, millions of gigantic trees 

 being buried beneath the raging floods. 



The great amount of carbonic acid removed from the atmo- 

 sphere by the luxuriant vegetation thus entombed, rendered 



