252 



LYELL'S ELEMENTS OF GEOLOGY. 



Fossil Plants of the Coal Strata, 



Fig-. 262. 



S igmnruijlcoidcs, Broiig. Oiu;-lourth of nat. size. (Foss. Flo. 32.) 



StigmaricB. — Fragments of a plant which has been called 

 Stigmaria Jicoides, occur in great numbers in ahuost every 

 coal-pit. It is supposed to have been a huge succulent water- 

 plant of an extinct family ; thin transparent sections of the stem 

 exhibiting an anatomical structure quite different from the wood 

 of any living tree.* According to the conjectures of some bota- 

 Fig. 263. anists, it approached most nearly to the 



family Lycopodiacem ; according to 

 others, to Euphorhiacece. Mr. Hutton 

 discovered one of these Stigmarise form- 

 ing a huge dome-shaped body, from which 

 twelve branches spread horizontally in 

 all directions, each, usually dividing into 

 two arms, from twenty to thirty feet 

 long, to which leaves of great length were attached. Dr. Buck- 

 land imagines these plants to have grown in swamps, or to have 

 floated in lakes like the modern Stratiotes.f 



I shall postpone some general remarks on the climate of the 

 Carboniferous period, arising out of the contemplation of its flora, 

 until something has been said of the contemporaneous Mountain 

 limestone and its marine fossils. 



Surface of another individtial of 

 same species, showing- form of 

 tubercles. (Foss. Flo. 34.) 



* Lindley, Foss. Flora, p. 166. • 



t Bridgew. Treat, p. 478. 



