342 PROFESSOR W. C. WILLIAMSON ON THE PLANTS 



of this province. These are stony casts, having irregular 

 and often large transverse markings, and enclosed in a thick 

 coat of lignite or fossil wood. In two specimens of the 

 latter kind, transverse sections of the portion with struc- 

 ture show cellular tissue, apparently with medullary rays, 

 and much resembling the wood of Coniferce. The fossils last 

 mentioned are probably, as suggested by Mr. Dawes with 

 reference to the British species of Sternbergise, casts of 

 the pith of trees. It appears evident, however, that the 

 first-mentioned species (named, I believe, Artisia approxi- 

 raata in Sir C. Lyell's list), was a plant having a very large 

 pith, and a comparatively thin woody envelope — in short, a 

 gigantic rush- like plant, perhaps leafless, and nearly cylin- 

 drical, like some modern species of Juncus." * 



At the meeting of the Geological Society which suc- 

 ceeded the reading of Mr. Dawson's memoir, Mr. J. S. 

 Dawes communicated his " Observations upon Sternbergiae." 

 He " does not agree in the conclusions of Mr. Dawson, 

 that herbaceous endogens may sometimes have produced 

 the columnar forms, usually referred to the pith of conife- 

 rous and other large trees. He thinks, that although the 

 appearance in question may indicate that the fossil is not 

 that of a true dicotyledon, it must still have been the in- 

 terior cellular portion of an arborescent plant, like Lepido- 

 dendron; the supposed bark being the vascular system 

 or sheath surrounding the pith, which has adhered during 

 decay to the medullary column, and sometimes been changed 

 into coal." -f- 



The investigations of M. Corda at length revealed the 

 fact, that some of the objects previously regarded as Stern- 

 bergise and Artisiae, were but the medullary cylinders of a 

 genus allied to Lepidodendron, which he terms Lomato- 

 phlois ; and which, as well as the Pachyphleus of Goeppert, 



* Proceedings of the Oeol. Society, London, No. 6, Jan. 1846. 

 t Ibid., No. 6, p. 139, 1846. 



