121 



ing those who have regarded them as the petrified remains of terres- 

 trial mushrooms. 



The shape of these bodies approaches so nearly to that of a mush- 

 room, as to fully authorize the name by which they have been gene- 

 rally distinguished by oryctologists. This resemblance has, however, 

 led to an erroneous mode of describing them ; every author having, 

 as Mr. Walch has done, in his description of these fossils, considered 

 the convex part as the superior, and the concave as the inferior, as is 

 the case with terrestrial fungi. But analogy teaches us, that these 

 bodies grew in a contrary manner ; the pedicle, by which they were at- 

 tached to other bodies, proceeding from the centre of their convex 

 part, and their concavity being, of course, on their superior part. 



The fungiform fossil, Plate VIII. Fig. 5, has a considerable conca- 

 vity on its superior part, and a corresponding convexity on its inferior 

 part. It is formed by tolerably distinct radiating lamellae, or plicse, 

 which, passing from the centre to the circumference, are frequently 

 seen to divide, and then again unite ; thus forming a species of inos- 

 culation. This structure is here shewn on its inferior surface, where 

 the laminae may be seen concentrating themselves, in that part which 

 had been continuous with the pedicle. 



On comparing the radiating lamellae, of which this fossil is com- 

 posed, with those of the alcyonium, depicted Plate XI. Fig. 3, this 

 similarity will be directly perceived. In both these fossils it will be seen, 

 that the lamellae frequently unite, as it were, by inosculation, and 

 are but rarely connected by interposed transverse processes. In thia 

 fungiform specimen, this peculiarity of structure, shewn on its infe- 

 rior surface, is equally evident on its upper surface, which, however, 

 is not here represented ; since the general idea of the appearance 

 yielded by the concavity of its superior surface, will be sufficiently 

 obtained by the view given of the next fossil. 



A very slight examination of the upper surface of this fossil ulcyo* 

 nium, Plate XL Fig. 7> will be sufficient to enable you to perceive 



VOL. II, ft 



