which rsie small papillce, like tubercules ; but which, being sunk in 

 the hollows, hardly ever rise above the general surface. A sub- 

 stance with a rough imbricated surface, and about one sixteenth of 

 the thickness of the whole fossil, is frequently found passing 

 through the centre of the cylinder, but more to the compressed 

 side ; and frequently a sulcus, one edge of which rises into a sharp- 

 ish ridge, may be observed to run in a line parallel with it. 



No conjecture, on which we can venture to rely, has yet been 

 offered with respect to this fossil. The Arbor Lavendulce Foliis, 

 Dr. Woodward says, hath studs, like these, and set in the same 

 quincunx order. Mr. Whitehurst thinks it most resembles the re- 

 mains of an Euphorbia, of the East Indies*. Indeed, there would 

 be little difficulty in referring it, either to the genus Euphorbia, or to 

 Cactus, were it not for the difficulty of explaining the nature of the 

 internal substance. The surfaces, both internal and external, are 

 frequently covered with a bituminous matter; the interstice being 

 closely filled with stony matter, which would dispose to the sus- 

 picion of their having been distinct vegetable bodies, which acci- 

 dent has thus united ; but, on the other hand, the frequency with 

 which they are found connected, and the similarity of the mode 

 in which they always appear to have been united, seem ta point 

 out that union to be natural, and hot accidental. Dr. Woodward 

 described this internal body, in his earlier specimens, as a medulla 

 or pith; but afterwards, a more careful view of this body, he 

 says, brought him to think it rather a commencement or beginning 

 of a branch, arising out of the main trunk -f. The data which 

 we possess would almost lead to the supposition, that the plant, to 

 which this fossil owes its origin, was of the succulent kind, which 

 contained a more solid part in. its succulent substance but con- 



* Inquiry into the Original State and Formation of the Earth, p. 203, 

 f. Catalogue of English Fossils, Part JL, p. 60. 



