6 



a Mushroom-button, seems formed in a similar way, with 

 trifling differences in the circumstances; as the lower figure 

 does also, which resembles an Acorn. The crystallization 

 and metallic appearance help to undeceive. However, this is 

 not always the case; and even this might, from its rugosity, 

 often having the appearance of the shagginess in a Mush- 

 room, or of the squamae on the cup of the Acorn, mislead 

 those who do not pay regard to the crystallization natural 

 to Pyrites. The cracks resembling stripes in the left-hand 

 Mushroom-like figure help a little to favour the deception. 

 It may not be amiss to observe, that on Sheppy Isle Mush- 

 rooms are extremely abundant ; and this may have given 

 rise to the idea of their being petrified, though any less 

 fugacious Fungus might have stood abetter chance of being 

 petrified. This sort of Pyrites is extremely common in ar- 

 gillaceous marl all over the kingdom, and it varies infinitely. 



