FOSSIL INVERTEBRATED ANIMALS. 471 



more than a foot in height. On a level with the soil might jbe 

 distinguished the knots, the ligneous layers, and all the other 

 durable accidents of vegetation. Some stems were more than 

 a foot in diameter. Lesueur, P^ron, and Bailly, found similar 

 petrifactions in the Island of Decres, in that of Josephine, 

 and on some points of the lands of Leuwin, of Edels, of En- 

 dracht, and of White. They were leaves, fruits, branches, 

 and roots of vegetables ; bones of quadrupeds, and even their 

 excrements. They have endeavoured to explain this forma- 

 tion by saying, that the very line calcareous and siliceous 

 sand, which borders the coasts of this new continent, is raised 

 by the wind, deposits itself on bodies, and becomes incrusted 

 there, and subsequently assumes so much solidity, that if the 

 branches of this sort of lithophytes be broken while the in- 

 crustation is recent, the ligneous tissue may be observed en- 

 gaged in a solid case^ and without any remarkable alteration. 

 But, in proportion as the calcareous envelope increases, the 

 wood becomes disorganized, and changes by invisible degrees 

 into an arid and blackish detritus. Then, the interior of the 

 tube is as yet empty, and preserves a diameter pretty nearly 

 equal to that of the branch which served it for a mould. — 

 Finally, this tube finishes by becoming obstructed^ and filled 

 with quartzose and all calcareous particles. Some years 

 elapse, and all is converted into a mass of sandstone. At 

 this last period, the arborescent form alone indicates the an- 

 cient state of vegetation. 



In certain parts of New Holland there exist elevated downs 

 formed of very fine sand, susceptible of a solidification more 

 or less rapid — at the reverse of these mobile hills grow various 

 species of arbustae, and even large trees, such as Banksia and 

 Eucalyptus. In such a position, all the sand which the rains, 

 winds, and storms precipitate from the summit of the downs, 

 deposits itself at the foot of these trees : it rises insensibly 

 along their stem, reaches their first branches, and concludes, 

 in the long run, by burying them under its ever-increasing 



