1911-12.] • r ,» 



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BIBLIOGRAPHY AND HISTORY. 



Walch, of Jena : — Natural History of Petrifactions — 

 Nurnberg, 1769. Described and figured beekite on some fossils : 

 probably the earliest reference of importance on the subject. 

 About this time, as detailed by Wickes, there were numerous but 

 unprofitable speculations as to its nature. 



Leopold von Buch : — On the Silicification of Organic Sub- 

 stances, etc. — Berlin, 1831. Described beekite accurately and 

 established its siliceous composition. From his observations he 

 inferred that the carbonate of lime was not replaced directly by 

 silica, but that only the organic matter was acted upon directly. 

 His most important remarks concerning its origin consist in his 

 description of knobs and whorls of chalcedony as " similar to 

 wave action.'" 



M. Alexandre Brongniart : — Essay on Orbicular Silica — 

 Paris, 183 r. Also described beekite accurately and laid stress 

 upon the influence of organic matter in the silicification. 



Dr. Henry Beeke, Dean of Bristol from 1814-1837, is 

 recorded to have drawn the attention of English Geologists to the 

 occurrence of this mineral in the neighbourhood of Bristol. 



Petzholdt : — Silicification of Organic Bodies — Halle, 1853. 

 Described the "warts and rings of silica" on fossil shells, and went 

 carefully into the question of the origin of beekite. He concluded 

 that the silicification always commenced at the surface of the 

 shell, that in every case it was the carbonate of lime which was 

 acted upon, and that there was no evidence to shew that organic 

 matter was necessary for silicification. He also recorded that the 

 silicification of shells is not always accompanied by the beekite 

 formation. 



Bischof: — Silicified Organic Remains — in his textbook of 

 •• ( 'hemical and Physical Geology," 1855. Went carefully into the 

 question of the silicification of shells. Observed that the space 

 required by the silica deposited was much greater than that of the 

 calcareous substance replaced. Compared the penetration of 



