On the Traces of a Vast Ancient Flood. 73 



vial hills. In connection with this remark it is necessary to 

 add, that, according to Professor Sefstrom, an a^is seldom more 

 than half a mile in length ; and that when it seems longer, it 

 Avill be found that a new as has commenced at the end of the 

 former one, and in a similar direction, from north to south, 

 though not exactly as a prolongation of the first, but somewhat 

 to a side. These remarks, which convey a much more distinct 

 idea of the asnr than can be obtained from LyelFs account, 

 make it also apparent why asar ai'c not every where met with ; 

 for they can only exist where the surface presented isolated 

 rocks of great hardness and compactness as a protection against 

 the flood, and as a place for the accumulation of the pebbles 

 transported by it. 



On the Condition of Fossil Plants, and on the Process of Petri- 

 faction. By H. R. GorPEUT.* 

 The idea of petrifaction has, owing to too great an extension 

 of the signification, been always employed to denote all fossils 

 which had previously been organic beings, whereas it is suited 

 to only a limited number of them. In the coal and coal slates 

 of the older coal and transition form.ations, we meet with plants 

 carbonized ; though it is not always the whole substance of the 

 vegetable we find thus changed, but frequently only its remains, 

 in the form of an easily separated film, or, indeed, only a mere 

 impression. Very rarely we see between the slaty layers the 

 plant, as it were in a dried state, and still perfectly flexible. At 

 this moment I possess two such specimens, which, in Silesia at 

 least, are extremely scarce. One is a seed discovered by Mr 

 Beinert an apothecary at Charlottenbrunn, in the mine of So- 

 phia, which is situated in a coal-formation, containing porphy- 

 ry, and the other is a new fern, belonging to the genus Ale- 

 thopteris, from the clay ironstone mines near Kreuzburg, in 

 Upper Silesia, and which was found by Dr Meyer, in a whit- 

 ish clay, accompanied by Catamites cannceformis, Sigillarla 

 organum, and Alethopteris Ottonis. The seed exhibits under 

 the microscope a perfect ceUular structure, (more I could not 

 determine) ; but the fern presents not only the striped vessels of 



• From Poggendorff'i Annaien der Physik und Chemic, vol. xxxviu. 1836. 



