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XXyill. — THE PHOSPHORITE NODULES OF PODOLIA — 

 NOTES EY J. P. O'REILLY, Professor of Mining and 

 Mineralogy, Royal College of Science, Ireland. 



[Eead, March 17, 1884.} 



At a recent Meeting of the Natural Science Section of the Eoyal 

 Dublin Society, Professor Yalentine Ball submitted for examination, 

 and made some remarks on, specimens of the globular or spherical 

 concretions of Phosphorite imported into this country from Podolia, 

 in southern Eussia. Their singular form, their remarkable size, 

 and radiated fibrous structure, excited curiosity and discussion as to 

 their origin. Wishing to arrive at some solution of the problem thus 

 apparently presented, and assuming that a mineral of this remark- 

 able character and of such industrial importance must have under- 

 gone chemical investigation and been scientifically noticed, I had 

 recourse to the authorities at hand in the College Library, and was 

 enabled to get from them a sufficiently detailed account of the 

 mineral itself, of the nature of its deposits, and its probable origin. 

 At the same time I received, through the kindness of Mr. N. Stad- 

 nicki, son of Count Stadnicki, on whose estates in Podolia large 

 deposits of this mineral exist, a fine collection of the balls in dif- 

 ferent states, which enable me, I consider, to push the question a 

 stage further than that arrived at in the memoirs which I am about 

 to cite. 



The first notice which I met with was the excellent article on 

 Phosphorites, forming one of the parts of the Encychpedie de 

 Chimie de Fremy (tom. v., 1st section, 2"'^^ partie, p. 89), wherein 

 the locality of the deposit is noticed and a summary given of a 

 memoir on these phosphorites, by Fr. Schwackhofer, published in 

 the Jahrhiich der Kais. K'dn. Qeolog. Reichsanstalt, 1871, xxi. Band, 

 p. 211. This memoir is very complete, and accompanied by plates. 

 He opens by explaining that the Silurian formation, which extends 

 over a great part of Northern Bukovina and Eussian Podolia, is 

 mainly represented by compact and highly fossilised limestones 

 and clay slates. Directly on these rest regularly stratified beds of 



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