22 



at the junction of the two halves at the upper end of the 

 column is very deceiving, being formed from somewhat 

 rounding facets, often scarcely discernible, but by these 

 means become more conspicuous — see the last description. 



This specimen was lent me by my friend Mr. Lowry, 

 who met with it last summer, and first discovered this 

 remarkable Mackle. 



It is prettily placed in the hollow of the shell among 

 the Limestone, which has on the left hand somewhat en- 

 veloped the mineral pith, and crystallized about the bub- 

 bles. 



