50 



CARBONIGENOUS ERA. 



FIG. 27. 



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. It is to 

 be remarked that plants of this kind 

 (forming two genera, the most abundant 

 of which is the calamites) are only re- 

 presented on the present surface by 

 plants of the same family : the species 

 which flourished at this era gradually 

 lessen in number as we advance up- 

 wards in the series of rocks, and disap- 

 pear before we arrive at the tertiary 

 formation. 



The club-moss family (lycopodiacece) 

 are other plants of the present surface, 

 usually seen in a lowly and creeping 

 form in temperate latitudes, but pre- 

 senting species which rise to a greater 

 magnitude within the tropics. Many 

 Calamites cannceformis. 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. Like the ferns and equisetacese, they rise to a prodi- 



FIG. 28. 



Lycopoditcs pinnatus. 



