Chemical composition of a P2O5 rich concretion from the Challenger expedition, Station 143 off Cape of Good Hope

Among the geological discoveries of the end of the 19th century, one of the most remarkable and certainly most important from the economic point of view, is that lime phosphate deposits have been recorded at various levels in a great many fields. The subsequent development given to the phosphate industry by that of agriculture needs have attracted a great interest in phosphate deposits. This, interest quickly developed for the phosphatic concretions dredged durin the Challenger expedition in the vicinity the Cape of Good Hope and in the Indian Ocean in a line drawn South from Africa to Marion Island. This paper describes the sedimentary environment of these finds and measurements of their chemical contents.