7€ Goppert on Fossil Plants, and on 



the nerves of the leaves, the cellular tissue of the parenchyma, 

 the net-like epidermis, but even also stomata, just as we find 

 in the ferns of the present day. On heating it, there remains 

 behind a skeleton composed of potash, similar, according to my 

 observations, to the skeletons left by recent ferns,* in which in- 

 deed, the jointed rings of the sporangia are also similarly con- 

 stituted. A drop of water destroys the whole structure, and 

 dissolves every thing except an exceedingly minute residue of si- 

 lica. These facts are of importance in a geological point of 

 view, as they prove decisively that this fern, neither before, af- 

 ter, nor during its envelopment in the clay, could possibly 

 have been exposed to a long-continued agueous action ; Jbr 

 had such been the case, no trace of so very soluble a salt as 

 potash icould have j-emained. The investigations of Karsten 

 prove that water, when it acts during the formation of coal, 

 produces this effect; for he found that the ashes of fossil wood 

 and of brown coal contained no trace of fixed alkali. -|- 



If we place recent ferns between soft plates of clay, then dry 

 them in the shade, and gradually expose them to a red heat, 

 we obtain products bearing a striking resemblance to fossil 

 plants. Nay, according to the different degrees of heat em- 

 ployed, we obtain the plants completely fixed in the clay, and 

 varying from the dried brown to the perfectly cai'bonized con- 

 dition, but more rarely presenting a shining black appearance ; 

 and by continuing the red heat, after the perfect destruction 

 of all organic matter, we obtain an impression, or what was 

 by the older lithologists termed a stone-kernel (steinkern). 

 It is not uninteresting to remark, how the small quantity of 



* The following additional observations have been subsequently published 

 by Mr Goppert: " We can easily convince ourselves of the existence of this 

 skeleton in every plant, by burning the latter at a candle, and afterwards 

 placing it carefully under the microscope. It will be easy to recognise the 

 original structure of the plant before it falls to pieces. This is also possible 

 with extremely thin carbonized sections. Thu.«, for example, the spiral ves- 

 sels of the Taxus can be observed without difficulty. It would appear, that it 

 is only owing to the want of proper precautions that we cannot always discover 

 the vegetable structure in coal.'' 



+ Archiv fur Berghau vnd Huftentcesen ; edited by Dr C. J. B. Karsten 

 vol. xii. part 1. Berlin, 1836. " Examination of the Cavbonaceo'us Substances 

 of the Mineral Kingdom in general ; and more especially of the composition 

 of the various kinds of coal occurring in the Prussian Monarchy," p. 29. 



