98 Mr. A. II. Church on the Composition, 



the nuclei are slightly siliceous, but in no case more so than 

 ordinary limestones are." 



A correspondent at Exeter first directed my attention to 

 these singular fossils, and not only gave me a large number of 

 specimens, but much valuable information and many useful hints. 

 The following interesting remarks are extracted from a letter 

 lately received from this gentleman : to some of his remarks I 

 shall have occasion to refer when detailing my own theory and 

 experiments. 



" The chief locality for them in this county is Torbay : I have 

 heard that they are found at the Ness near Shaldon, and I have 

 a few from North Tawton. Beekites proper are confined to the 

 New Red Sandstone, although a structure very near akin to it is 

 found in the Mountain Limestone (I have one specimen) ; the 

 same may be said of the Lias and the Greensand, but there the 

 rings (concentric ridges) are not so large. I have often thought 

 whether this peculiar arrangement is not due to the displacement 

 of carbonate of lime by silex which takes place in fossilization, as 

 the shells must originally have been carbonate of lime. The 

 experiment I tried with hydrofluoric acid was on mammillated 

 or bubble chalcedony, to see if there were any connexion between 

 this structure and the Beekite. I thought the latter was the 

 former with the tops of the mammillations either dissolved or 

 rubbed off; the appearance of the chalcedony after the application 

 of the acid rather favoured that supposition. I have seen Beekites 

 with the mammillated structure on a part of them, and the 

 Beekite structure on the other, passing gradually from the one to 

 the other. The mammillated structure I speak of is found 

 abundantly in the interior of the flints at Haldon, and perhaps 

 in the Chalk also. I shall send yon the Beekite which effervesces ; 

 you will find that as the carbonate of lime is dissolved, the rings 

 more and more appear. I shall also send a few specimens of 

 shells from the Greensand of Haldon. With your glass you 

 will see that they are entirely made up of rings, such as are 

 shown in the Beekites on a larger scale." 



Both Mr. Pengelly and Mr. Kesteven speak of the fragments 

 of coral and of limestone, to which they refer as the basis of 

 Beekite, as undergoing decomposition spontaneously; and it 

 seems that most other writers who have attempted an explanation 

 of the phenomena presented by these singular fossils, have made 

 the same assumption. We meet, for instance, with such explana- 

 tions as the following : — " It seems probable that, after the forma- 

 tion of the conglomerate beds, many of the calcareous pebbles 

 in them continued to decompose at the surface, and thus allowed 

 water, holding siliceous matter in solution, to pass through the 

 rock ; and that, in passing, it deposited the chalcedony on the 



