Note 29 — THE CHEMICAL RELATION OF IRON AND MANGANESE IN SEDIMENTARY ROCKS.
Reading edition
Bischof suggests that the action described by Fresenius causes the separate deposition of iron and manganese; and also that it explains the occurrence of large deposits of manganese ore in regions where the iron ore contains least of that ingredient. (See Elements of Chemistry and Phys. Geol., Vol. III., pp. 531–532.)