On the Mineral Cyprusite. By Julien Beby. 191 



ferrous sulphate with ahiminic sulphate. As the solution passed 

 over the rocks, or lay exposed in situ, the ferrous sulphate would, 

 under the actinic influence of warm sunshine, be more or less com- 

 pletely converted into ferric sulphate, depositing at the same time 

 hydrated ferric oxide. This latter, acted upon by the mixed solution 

 of ferrous and ferric sulphates, will readily form any or all of the 

 possible basic ferric sulphates. 



Looking at the cyprusite from a geogenetic aspect, we must 

 admit that depression below the level of the sea and subsequent 

 upheaval at a later period must have taken place to explain its 

 present situation and its contained marine organic remains. 



Possibly great fissures, corresponding to the position of the lodes, 

 may have previously existed in the estuaries of streams or bottoms 

 of small lakes or pools. These, for a long time, may have been in- 

 accessible to the sea and to the marine polycistins (Radiolaria), and 

 the ferrous and ferric sulphates may have been subjected to the 

 reducing action of organic matter, restoring them to their original 

 form, disulphide of iron, which would be deposited in the fissures. 

 Once the fissures were so filled up, geological depressions may have 

 admitted the sea with its living organisms, and thus entirely altered 

 the conditions. The reducing agent being removed, the basic ferric 

 sulphates would be deposited above the pyrites, and the polycistins, 

 poisoned by the soluble salts of iron and alumina, would supply 

 the existing organic silica. 



The fact of the cyprusite occupying only the upper portion of 

 the deposit is attributable to the fact that alteration of the lode 

 had only progressed to a limited extent at the time of its sub- 

 mersion. 



The formation contains tens of thousands of tons, and is 

 certainly a very remarkable one in every respect. It seems unique 

 of its kind in the world, and deserves a more complete study than 

 I could bestow upon it in a flying mule-back visit to the Chry- 

 sophou district during the hottest and most trying period of the 

 year, and while engaged on professional work.* 



* I forward a few slides of cyprusite for the cabinet of the Society, prepared 

 for microscopical examination, as well as some slides of the insoluble residue 

 after treatment with acids, showing the polycistins ; also some of the crude 

 material as well as some of the organic silica washed out of it, for distribution to 

 Fellows iuterested in this branch of research. 



