212 Mr. Stokes's Notice respecting a piece of Recent 



ferous wood, which are as distinct in the fossil as in the recent wood. Prom 

 this high state of perfection, we have every degree of condition, down to the 

 very last stages of decay ; hence it appears, that there is not anything in the 

 state or condition of the wood, which has influence upon the process. 



Sometimes we find petrifactions of the most close grained, and probably 

 the hardest kinds of wood, in good condition ; at other times, we meet with 

 stems of a soft and succulent character, and there are also instances of the 

 complete silicification of the young leaves of a palm tree, when just about to 

 shoot forth, and in that state which, in the West Indies, is called the cabbage 

 of the palm. 



The different states in which the stems of palm trees have been preserved, 

 are also deserving of notice. These consist of a cellular tissue, among which 

 are separate fascicles of ligneous vessels, which rise through the stem. In 

 some few cases, the cellular tissue is well preserved, while scarcely any of the 

 vessels or woody fibres remain, and the spaces they occupied, are now hollow 

 passages through the specimen. In other cases, the cellular tissue has dis- 

 appeared, and the bundles of vessels alone are well preserved. Other cases 

 occur, in which both the cellular tissue and the vessels, are preserved in good 

 condition. On these facts, I would remark, first, that where the cellular 

 tissue has been petrified, and the vessels have disappeared, the process must 

 have taken place, soon after the wood had been exposed to the action of 

 moisture, because the cellular part would soon decay; and that it was then 

 suspended, as in the cases described in the beginning of this paper. Se- 

 condly, where the woody vessels alone have been preserved, 1 conclude, 

 that a time elapsed before the process of petrifaction commenced, during 

 which the cellular tissue had decayed. Thirdly, that where both structures 

 are preserved, the process had commenced at an early period, and continued 

 without interruption till it was completed throughout. 



There are also some cases, in which hollow dicotyledonous trees have been 

 petrified, and in these cases the middle part is filled up with chalcedony and 

 agates, sometimes leaving cavities which are coated with crystals of quartz. 

 1 have also seen cases, in which the cellular tissue only of the stems of 

 palms has been preserved, and the structure of woody vessels had disappeared, 

 but the places where they had been, have been filled up (doubtless subse- 

 quently) with agates. 



In conclusion, I have only to state my regret, that the information I have to 

 offer is so scanty, and to express the hope that this subject may be taken up 

 by others, who have better opportunities, and more knowledge and talent for 

 conducting the inquiry. 



