114 PECKHAM — THE GENESIS OF BITUMENS. [April , 



8. It is not alone through a study of the crystalline rocks that 

 the chemistry of the primeval world is interpreted. By a compari- 

 son of the kind and amount of salts dissolved in the waters of the 

 primeval ocean that are enclosed in palaeozoic strata with the kind 

 and amount of salts dissolved in the waters of the present ocean, 

 Dr. Hunt has shown that from the earliest geologic time until the 

 present, alkaline carbonates derived from the subaerial decompo- 

 sition of feldspar have been carried into the ocean by streams, and 

 the calcium and magnesium in the ocean have been successively 

 precipitated as carbonates, producing limestones and dolomites, 

 while common salt and calcium sulphate have accumulated in the 

 present ocean, the former in large excess. There is abundant 

 evidence that this palaeozoic ocean was hotter than the existing 

 one, as well as more saline, while it is equally evident that during 

 long intervals its sediments carried down vast quantities of the 

 remains of vegetable and animal life. He has further repeatedly 

 shown in what manner these sediments were influenced by the 

 organic matters that were enclosed in them. In his essay on '' The 

 Chemistry of Natural Waters," he has shown that argillaceous 

 sediments deprive waters of the organic matter in solution by form- 

 ing a compound containing an organic radical. He says, "There 

 is reason to believe that alumina is under certain conditions dis- 

 solved by waters holding organic acids," and cites melite and 

 pigotite as examples of the compounds formed. He further shows 

 that organic matter in water reduces sulphates to sulphides, produc- 

 ing from soluble sulphates of lime and magnesia carbonates of the 

 basis, with hydrogen sulphide, free sulphur, or a metallic sulphide ; 

 the hydrogen sulphide being converted by slow oxidation or com- 

 bustion, followed by absorption of oxygen directly into sulphuric 

 acid, which is again, when in contact with organic matter, reduced 

 to hydrogen sulphide. 



He says with reference to the water of palaeozoic brine springs, 

 " In the large amount of magnesium chloride which they contain, 

 these waters resemble the bittern or mother-liquor which remains 

 after the greater part of the sodium chloride has been removed 

 from sea-water by evaporation The complete absence of sul- 

 phates from many of the waters points to the separation of large 

 quantities of earthy sulphates in the Cambrian strata from which 

 these saline springs issue ; and the presence in many of the dolomite 

 beds of the Calciferous sand rock of small masses of gypsum, 



