402 



and all the other different species of fossil wood, are the appearance 

 of oval or circular spots, from the size of a crow-quill to that of a 

 goose-quill, filled with a substance generally of a more crystalline 

 appearance, and of a different colour from the ground. The sub- 

 stances with which these spots are filled, are sometimes evidently 

 calcedonic ; sometimes they resemble cornelian ; and sometimes they 

 are complete onachyne agate. The margins of these spots are, com- 

 monly, well defined, by a circular or oval line ; in some instances 

 this line is hardly perceivable, but in others it is so thick, that be- 

 ing continued through the substance of the stone, it describes a per- 

 fect tubule. In the centre of these spots may be mostly discovered 

 starred bodies, differing in colour from the rest of the spot : the 

 stars varying in the number of their rays; some having only four, 

 whilst others have five, six, seven, and even eight rays. These stel- 

 lated bodies pass through the substance of the stone, so that the 

 Same star will be seen on the upper as on the under side. The 

 variegated surfaces of these stones give them a very curious ap- 

 pearance: the spots, which are of various colours, red, brown, 

 bluish white, &c. are generally quite distinguishable from the 

 ground ; whilst the central star is also, frequently, plainly distin- 

 guishable, from its differing again from the colour of the spot which 

 surrounds it. Thus a most pleasing mottled surface is formed, 

 such as cannot be described, and such as cannot well be copied 

 by art. 



No inquiries which have been made, respecting these stellated 

 substances, have as yet terminated satisfactorily. Mr. Walch ob- 

 serves, that, in some of these stones, their ligneous origin is ren- 

 dered indubitable ; the fibres of the wood being discoverable in the 

 transverse, as well as in the longitudinal section of the fibres; 

 whilst in others, he allows it is by no means evident. But, as he 

 remarks the grand difficulty exists in determining the nature of 

 those substances which assume this stellated form, and which possess 



