On a Specimen of Nummulitic Rock from the neighbourhood of Varna

Abstract

In offering to the Society the accompanying specimen of Nummulitic Limestone from Buyuk Aladyn in the neighbourhood of Varna, I am desirous of making one or two observations respecting its occurrence. The specimen was forwarded to me by my brother. Col. F. W. Hamilton, Grenadier Guards, who, in a first communication (since published in the Literary Gazette, July 29, 1854, p. 690), expressed an opinion that the hollow depressions which occur abundantly on the surface of these limestone hills were the result of artificial excavations, and that the columnar-looking rocks which remain standing in the middle, were the pillars by which the roof was originally supported. In a subsequent letter he observes that the hollow depressions occur in so many parts of the country on the limestone plateau, that he believes he must give up his former opinion that they are artificial, and look upon them as natural depressions. On referring to Boué's ‘Esquisse Géologique de la Turquie d'Europe’ (Paris 1840), I find that, after mentioning the fact of the vast development of the cretaceous formations in Turkey (p. 17), he alludes to the occurrence in Bulgaria of enormous masses of Orbitolites , constituting a portion of the nummulitie group. Further on (p. 21), he observes that the upper beds of these cretaceous rocks are full of Orbitolites , to which he has given the name of O. Bulgarica . He also alludes to the great prevalence of caverns and grottos in some portions of the cretaceous beds of Turkey in Europe, many