c ^6 [Proc. B.X.F.C., 



BEEKITE, OR CYCLOIDAL CHALCEDONY. 



The monthly meeting of the Geological Section was held in 

 the Museum on Wednesday evening, 27th March, when Mr. 

 James Strachan gave a most interesting lecture on " Beekite, or 

 Cycloidal Chalcedony,'' with an account of his original investi- 

 gations into its origin. In the unavoidable absence of the Chairman 

 of the Section, Mr. James Orr presided. 



Mr. Strachan said : — This paper is intended to supplement 

 the excellent Monograph* recently published by W. H. Wickes, of 

 Bristol, who has given us a very concise account of the history and 

 distribution of this mineral. I shall deal more particularly with 

 the question of its probable mode of origin as revealed by micro- 

 scopical and chemical analyses. This involves a rather more 

 exhaustive account of the literature on the subject, with special 

 reference to the various authors' geogenetic theories, than that 

 presented by Wickes. The various writers on the subject will be 

 dealt with briefly in chronological order, and finally I shall give 

 the results of my own investigations. 



It is here necessary, however, to state exactly the nature of 

 " beekite," a mineral species not generally described in mineral- 

 ogical text-books. Beekite is a form of chalcedony of secondary 

 origin, found encrusting and replacing the calcareous remains and 

 skeletons of such fossil marine organisms as mullusks, corals, and 

 encrinites. Its typical form consists of minute globules and discs 

 surrounded by concentric wheels or whorls of chalcedony. It 

 also occurs in small masses composed of aggregates of globular 

 and vermicular forms of the same substance. The name "beekite"' 

 is derived from its discoverer in England, a Dr. H. Beeke, of 

 Bristol, but it has also been described as "annular" and "orbicular" 

 chalcedony. The name " cycloidal," which I have applied to it, 

 is due to Ruskin, and in distinction to ordinary chalcedony, which 

 is " spheroidal " in form, the word seems most appropriate. 



* "Beekite."— Proc. Bristol Nat. Soc, Vol. II., Pari III., 1910. 



