120 



parts, the quadrangular spaces mentioned in the preceding fossil, and 

 which are, in this fossil, disposed with a considerable degree of regu- 

 larity. This fossil is apparently of a similar substance with the two 

 former, and was obtained from Randenberg near Schafhausen. 



A circumstance, particularly deserving your attention, is observa- 

 ble in the three last fossils. In the first, the perpendicular lamellae are 

 slightly connected by very few transverse processes, and by still fewer 

 ramifications : in the second, the connection is preserved chiefly by anas- 

 tomosing ramifications of the lamellae; and in the last, almost entirely 

 by transversely disposed processes or filaments. This difference is 

 very obvious ; and if the two fossils, Fig. 1 and Fig. 9> had only been 

 obtained, no one would have hesitated to have regarded them as dis- 

 tinct species; but in the structure of the one, Fig. 3, so much of the 

 characters of both the former is to be found, as necessarily connects 

 them together, and shews that they all are referable to the same 

 species. 



Hence you may perceive how little can be done, in the present 

 state of the science, in forming any useful classification of these fossil 

 animal remains ; since more opportunities are necessary to impower 

 any one to determine which may be considered as distinct species, and 

 which should be regarded merely as varieties. 



The two fossils, which I shall next place before you, will also, I 

 trust, serve to shew the difficulties which I have just spoken of. These 

 fossils, although differing so much in form from the preceding, pos- 

 sess the same kinds of structure which were observable in them : the 

 one being characterised by the connection between their lamellae 

 being kept up by inosculation, and the other by the means of inter- 

 posed transverse processes. Whether these two fossils should be con- 

 sidered as of the same species with the preceding, I will presently en- 

 deavour to learn. 



These fossils are of that kind which have been generally considered 

 as fungites, or petrified sea mushrooms ; nor have there been want- 



