NEAR ST. Mary's island, Northumberland 251 



almost entirely corroded, and the outer parts of the iron 

 plate oxidised. An analysis of the cementing matter has 

 been made by Dr. J. A. Smythe and found to contain a large 

 quantity of iron, a moderate amount of manganese, with 

 small quantities of aluminium, magnesium, and calcium, and 

 a trace of sodium, combined as carbonates, sulphides, 

 phosphates, and oxides. Silica was also present. The most 

 interesting compound occurring in it would appear to be the 

 large amount of ferrous sulphide. It is hoped to further 

 investigate the chemistry of the deposit. 



