70 



VESTIGES OF THE 



are arborescent, or of a tree-like size and luxuriance,* 

 The ferns of the coal strata have been of this magnitude, 

 and that without regard to the parts of the earth whei-e 

 they are found. In the coal of Baffin's Bay, of New- 

 castle, and of the torrid zone alike, are the fossil ferns 

 arborescent, showing clearly that, in that era, the present 

 tropical temperature, or one even higher, existed in very 

 high latitudes. 



In the sw^amps and ditches of Eughmd there grows a 

 plant called the horse-tail {equisetum), having a succulent, 

 erect, jointed stem, with slender leaves and a scaly catkin 

 at the top. A second large section of the plants of the 

 carboniferous era were of this kind {equisetacece), but, 

 like the fern, reaching the magnitude of trees. While 

 existing equiseta rarely exceed three feet in height, and 

 the stems are generally under half an inch in diameter, 

 their kindred, entombed in the coal beds, seem to have been 

 generally fourteen or fifteen feet high, with stems from 

 six inches to a foot in thickness. Arborescent plants of 

 this family, like the arborescent ferns, now grow only 

 in tropical countries, and their being found in the coal 

 beds in all latitudes is consequently held as an additional 

 proof that at this era a warm climate was extended 

 much farther to the north than at present. It is to be 

 remarked that plants of this kind (forming two genera, 

 the most abundant of which is the calamites) are only 

 represented on the present surface by plants of the same 

 family : the species which flourished at this era gradually 

 lessen in number as we advance upwards in the series of 

 rocks, and disappear before we arrive at the tertiary 

 formation. 



The club-moss family {lycopodiacece) are other plants 



* A specimen from Bengal, in the stairca'ic of the Uriii^h Museum, 

 is fortv-five feet hicrh. 



