332 PROCEKDINGS OF SOCIETIKS. 



their delicate leaves and soft integument, once j)ainted with ver- 

 dure, now blackened and replaced with inflexible carbon. The spe- 

 cimens now submitted with one exception, are all common coal 

 plants, but as no palm tree has escaped to tell the tale of their times, 

 they may, although not related, prove useful allies to the fruit with 

 which they were associates, and help to elucidate the obscure ques- 

 tion of the origin of coal. 



We have here then the Calamites (nodosus, I believe), a plant 

 which from its universal prevalence may almost be said to characte- 

 rize the coal-formation. Whether the coal-measures be sandstone 

 or shale — that is to say whether the deposits be sand or mud the ca- 

 lamites is always present — sometimes standing upright, perhaps in 

 the very mud from which it derived sustenance when living, in 

 which case the stem is cylindrical, but general prostrate and flat- 

 tened as in the specimens before us. It is usual to refer this plant 

 to the living order Equiseta, and to identify it with the horse-tail of 

 this country, and contrasting its superior size with that of its puny 

 prototype, the horse-tail never exceeding half an inch whilst cala- 

 mites fourteen inches in diameter have been discovered, it affords a 

 striking illustration of the more-than-tropical luxuriance of the 

 vegetation of the period to which it belongs. 



The next specimen is a portion of a flattened and partly decorti- 

 cated stem of the lepidodendron, a genus of extinct plants most re- 

 markable, as constituting a link in the vegetable kingdom which in 

 the existing creation is wanting. Although branched and furnished 

 with bark it was not of the coniferous or fir tribe, having no woody 

 axis The li/copodiacse to which it is supposed to bear the greatest 

 resemblance, luxuriates in a hot and humid climate, and hence the 

 occurrence of these lends force to the inference suggested by the 

 calaniilcs — that these plants were produced under those conditions. 



The other specimens are casts and portions of the stem of the 

 sigillaria or tree ferns, about which there has been so much discus- 

 sion between Professor Lindley and A. Bronsniart. Suffice it to 

 say, however, that they are most decisive proofs of an equatorial cli- 

 mate : and that the fossil specimens sometimes infinitely surpass in 

 size their living types under the most favourable circumstances of 

 humidity and climate. 



The last is a very remarkable and novel specimen to which the 

 title of Halonia regularis has been given, which I believe is all that 

 can be said about it. An uninitiated eye would recognize in it some 

 resemblance to the Cacti or Euphorbiie of our hot-houses, but it has 

 probably no precise counterpart in the flora of the present times. 



There is also a specimen of a striated stem which corresponds with 

 nothing hitherto described. 



I could find no specimens of stigmaria so common in other dis- 

 tricts — as in Derbyshire, for instance, where it is the predominating 

 fossil, and where, singular as it may appear, this cactus-like plant 

 furnishes, in some places, the chief material for the repair of the 

 roads. Nor did I discover anv traces of the foliage of ferns in which 



