from New South Wales. 157 



In some of the specimens, particularly in those which possesses 

 the property of absorbing fluids, there is not a single regular 

 pore to be seen. The medullary rays, which are extremely mi- 

 nute, and of a pale grey colour, are the only observable remains 

 of the vegetable structure. 



They are very much compressed, and bent throughout into a 

 zigzag form, exhibiting a very beautiful appearance. 



The petrified woods which you lately received from Mr Burnet 

 of Sydney, and which are stated to have been found imbedded 

 in the sandstone on the coast, in the vicinity of Newcastle, New 

 South Wales, are, like Mr Wilton^'s collection, decidedly Coniferaa. 

 They are all so much alike, both in external appearance and in- 

 ternal structure, that they might be considered as forming a 

 part of one individual tree. They are more or less of a greyish- 

 black colour. They are all considerably denser than any of the 

 specimens in Mr Wiltan*'s collection, and one specimen I exa- 

 mined has a specific gravity of 3.817. They are also less hard 

 than any of Mr Wilton's specimens. Some of them are hydra- 

 ted iron, others carbonate, and some red oxide. 



In consequence of their opacity, it is necessary to reduce 

 these specimens to the greatest possible thinness, before the in- 

 ternal structure can be seen. When that is done, the coniferous 

 structure appears in the most perfect state, there being not the 

 slightest deviation from the natural position either in the medul- 

 lary rays or concentric partitions. 



The whole of these specimens diff*er materially both in exter- 

 nal appearance, composition, structure, &c. from any one of Mr 

 Wilton's collection. .Indeed they so closely resemble several 

 specimens in the College Museum from Van Diemen's land, 

 that I should have pronounced them as belonging to that island, 

 had tlieir locality not been stated by Mr Burnet to be the sand- 

 stone in the vicinity of Newcastle, New South Wales. 



In the coal formation of New South Wales, as well as in the 

 older and newer deposits of that mineral in this island, conife- 

 rous fossils are the only remains of ligneous bodies, retaining an 

 organized structure, that have hitherto come under my observa- 

 tion. Various speculations might be indulged as to the cause 

 of this prevalence of Coniferae in coal deposits ; but I shall leave 

 it to you and others, who are much better qualified than I am, 

 to throw light on the subject. 



