419 



imbricated, surface, from which seem to proceed a considerable 

 number of thin, narrow leaves, by which it has been surrounded. 

 Its resemblance to any known plant is not sufficient to have allowed 

 any one to point out, with any confidence, the plant of which it 

 may have been a part. Scheuchzer thought it most resembled 

 " Equisetum, adhuc tenellum, in densam foliorum spicam, con-* 

 gestum; vel spica plantae alicujus hactenus ignota." Walch ima- 

 gined it to bear some analogy with the Myriophyllon, Lin mo i. Per- 

 haps, he says, it may be Millefolium aquaticum, flosculis ad folio- 

 rum nodos. The stalk, however, which, if not imbricated, has a 

 regular reticulated surface, proves it not to belong to either genus. 

 The ingenious Mr. Martin, in his descriptions of the petrifactions 

 of Derbyshire, considers this fossil as the stalk or stem of some lost, 

 or, at least, unknown vegetable, somewhat resembling a cone of the 

 fir-tree. 



The fragments contained in the nodule Fig. 3, and 4, are not suf- 

 ficiently perfect to lead to any conjecture, as to the plant to which 

 they belong. They, however, serve, with Fig. 1, and 2, already de- 

 scribed, to illustrate the circumstance of the two surfaces of the 

 divided nodule representing the same side of the leaf as will be 

 attempted to be explained in our next Letter. 



A similar specimen with that represented Plate V. Fig. 3. has also 

 been depictured by Volkman, from a schist from Silesia, whence this 

 specimen was also said to have been obtained. He describes it as 

 Rubia sylvestris, or molluga montana ; Gallium album latiiblium, 

 Gasp. Bauhin ; Gallium album, Tournefortii. M. Walch states it 

 to have been the opinion of M. Gunther, that it is the Rubia parva, 

 flore caeruleo, cauliculos per terram spargens, Joh. Bauhini. Lhwydd 

 has also figured it, Tab. V. Fig. 202. and describes it as Rubeola 

 mineralis, a fodinis Actonensibus, p. 12. Fig. 7- of the same Plate 

 seems to represent a part of the same plant, in an erect position, 

 manifesting it to be one of the verticillatce ; and, perhaps, also show- 



