PALvEOPHYTOLOGY : FOSSIL PLANTS. 269 



live on the shores of the Polar Sea, subsist at the present 

 day exclusively on fish and cetaceae, is alone sufficient to 

 shew that vegetable substances are not absolutely indispen- 

 sable to the support of animal life. After the devonian 

 strata and the mountain limestone, we come to a formation 

 in which botanical analysis has recently made the most 

 brilliant progress. ( 318 ) The coal measures contain not only 

 cryptogamic plants analogous to ferns,, and phsenogamoua 

 monocotyledones (grasses, yucca-like liliacese, and palms), 

 but also gymnospermic dicotyledones (coniferae and cycadere) . 

 We have already distinguished nearly four hundred species in 

 the coal formation, but of these I will here merely enumerate 

 arborescent calamites and lycopodiacece ; the scaly lepido- 

 dendron ; the sigillaria, sixty feet long, distinguished by a 

 double system of vascular fascicles, and sometimes found 

 upright and apparently having its roots attached ; the stig- 

 maria, approaching in some respects the cactacese ; an im- 

 mense number of fronds and sometimes stems of ferns, which, 

 by their abundance, indicate the insular character of the dry 

 land of that period ;( 319 ) cycaclese, ( 32 ) and especially 

 pilms, ( 321 ) though fewer in number than the ferns ; astero- 

 phyllites, with verticillate leaves, allied to naiades; and 

 coniferse, resembling araucarias, ( 322 ) having some faint 

 traces of annual rings. All this vegetation was luxuriantly 

 developed on those parts of the older rocks which had risen 

 above the surface of the water, and the characters which dis* 

 tinguish it from our present vegetation were maintained 

 through all subsequent epochs up to the last of the cretaceous 

 strata. The flora of the coal formation, comprising these 

 remarkable forms, presents a very striking uniformity of 

 distribution in genera, if not in species, ove? all the 



