116 Notice of Dr. MantelVs Medals of Creation. 



rasses and peat bogs ; in tufaceons incrustations, as decayed 

 wood, with the imprints of the leaves and stems preserved on 

 the solid masses of concretionary or crystalline limestone." 



" In the ancient deposits vegetables are found in two different 

 states. In the one, their substance is completely permeated by. 

 mineral matter; it may be calcareous, (lime,) siliceous, (flint,) 

 ferruginous, (iron,) or pyritous, (sulphuret of iron;) and yet both 

 the external characters and the internal structure may be pre- 

 served. Such are the fossil trees of the Isle of Portland, frag- 

 ments of which so closely resemble decayed wood, as to deceive 

 the casual observer, until by close examination of their texture 

 and substance he finds that they possess the weight and hard- 

 ness of stone. In the silicified wood, (that petrified by silex or 

 flint,) which abounds in many of the tertiary strata, the most 

 delicate tissue of the original is generally preserved, and by mi- 

 croscopical examination may be displayed in the most distinct and 

 beautiful manner. Calcareous wood also retains its structure, and 

 in many limestones leaves and seed-vessels are well preserved." 



" The ligneous coverings or the husks and shells of muciferous 

 fruits, or the cones and strobili of firs and pines, are frequently 

 in an excellent state of preservation ; and in some rare instances 

 indications of flowers have been observed. The parts of fruc- 

 tification in some of the fern tribe occur also in coal shale, and 

 in the grit of Tilgate Forest ; and even the pollen of Coniferas 

 has been found in tertiary marls associated with animalculites. 

 The resinous secretions of pines and firs are also found in a min- 

 eralized state. Amber is too well known to require any further 

 mention in this place, than that its vegetable nature is unques- 

 tionable ; this substance has been observed in its natural position 

 in trunks of Coniferee. The fossil resin of the London clay, 

 discovered at Highgate and the Isle of Sheppey, had a similar 

 origin." * * * " The diamond, which is a pure charcoal, is prob^ 

 ably a vegetable secretion that has acquired a crystalline struc- 

 ture by electro-chemical action." * * * 



" But vegetables occur not only in petrified stems, leaves, and 

 fruits, associated with other remains in the strata, but in beds of 

 great thickness and extent, consisting wholly of plants transmu- 

 ted, by that peculiar process which vegetable matter undergoes 

 when excluded from atmospheric influence and under great pres- 

 sure, into carbonaceous masses called lignite and coal. And there 



