90 



portunitj of fair comparison could be found, between the recent and 

 fossil alcyonia. 



This however is very far from being the case : and indeed when we 

 reflect on the transmutation which has taken place ; that a soft, gela- 

 tinous, or spongy substance, has become a hard and ponderous stone, 

 we cannot but be affected with a high degree of astonishment ; espe- 

 cially on perceiving, that this great and extraordinary change of sub- 

 stance has been accompanied by so little change of form. In conse- 

 quence of this I trust I shall be able to place before you many bodies, 

 even in a silicified state, which will immediately appear to have 

 been animals of this description, belonging to a former world. So 

 great indeed will be the variety of these bodies, and so perfectly well 

 preserved will they appear, as to render it necessary for me to say a 

 few words, respecting the state of preservation in which they are found. 



This is rendered necessary ; since the comparatively frequent ap- 

 pearance of these bodies, in a fossil state, appears to contradict a 

 position laid down in the former volume, whilst speaking of fruits, that 

 substances possessing a pulpy consistence were not likely to be found 

 in a fossil state ; since their decomposition would most probably take 

 place, with too much rapidity to allow of that change being effected, 

 on which their mineralization would depend. But a peculiarity of 

 structure exists in these animals, which exempts them from the in- 

 fluence of this law. It appears, as we have seen from the observations 

 of Marsilli and Donati, that these animals have blended, with their 

 gelatinous and carneous substance, innumerable minute spiculae, which 

 may be considered as the bones of the animal. These manifest them- 

 selves by the prickling sensation they occasion, on being handled, 

 which has obtained for some of these animals the name of the sea- 

 nettle. That these spiculae, formed of a hard and durable matter 

 may, in some, and especially that the spongy fibres and coriaceous co- 

 vering may, in others, keep up the form of the animal, for a sufficient 

 time to admit of the petrifactive process being accomplished, seems 



