The proof which I gave in June, 1891, of the production of “rich phosphate” by enrichment of phosphatic chalk through the influence of the Tertiary deposit called “bief,” enabled us to foresee the existence of similar rich phosphate in the London Basin; since phosphatic chalk, analogous to that which I had described or discovered in Picardy, especially at Hardivilliers and Hallencourt, had been discovered by Mr. Strahan and described by him in an interesting paper “On a Phosphatic Chalk with Belemnitella quadrata.”