THE 



GEOLO&ICAL MAGAZINE. 



No. XCVL— JUNE, 1872. 



I. — On some Fossil Wood feom the Lowek Eooenb. 



By W. T. Thiselton Dyer, B.A., B.Sc, F.L.S. 



(Plate VI.) 



THE Botanical Department of the British Museum possesses 

 amongst its collection of fossilized vegetable remains, sliced 

 for microscopic examination, a series of specimens of wood from 

 Heme Bay and the Isle of Thanet. These exhibit a structure which 

 has not hitherto been properly understood, but which proves to be 

 quite comparable with what is to be found in some recent plants. 



Fossil wood from this locality has long been known to collectors. 

 Mr. S. Gray gave the following account of it in the Philosophical 

 Transactions, in 1700 ^ : — " About half a mile from Eeculver, towards 

 Herm, there appears in the cliff a strata of shells in a greenish sand ; 

 they seem to be firm, but some of them are entire, but when you go 

 to take them from their beds they crumble to powder between your 

 fingers ; but that which is most remarkable is, that in the lower part 

 of the strata, where the shells are more thickly dispersed, there lies 

 scattered up and down portions of roots, trunks, and branches of 

 trees ; the wood is become as black as coal, and so rotten that large 

 pieces of it are easily broken with one's fingers. I know not what 

 depth these may lie, the strata's surface not appearing above two feet 

 from the beach, but I judge it from the superficies or top of the cliff 

 above 12 foot. I saw the stump of one tree standing upright, broken 

 off about a foot from the ground. I should have given a more par- 

 ticular account, but cannot find at present the note I took upon the 

 place. I shall only add that the shells were of the white Conchites." 



Mr. Dowker states that in the neighbourhood of Eeculver large 

 masses of silicified wood, often bored by Teredo, are found both in 

 the Woolwich beds and in the Thanet sands.^ 



The microscopic structure of the wood shows at once that it 

 belonged to an arborescent Dicotyledon. Fig. 1 (PI. VI.) represents 

 a transverse section of a " wedge" which is bounded on either side 

 by a medullary ray, and consists of woody tissue and large ducts. 

 The woody tissue is made up for the most part, as is usually the case, 



1 vol. xxii., p. 762. * Proc. Geol. Asso., vol. i., p. 343. 



VOL. IX.— NO. xcvi. 16 



