On the Disposition of Iron in variegated Strata

Publisher Website
Google Scholar
Abstract
O f those secondary changes which have modified the original chemical and physical constitutions of rocks none seem to have more largely affected their aspect than the recombinations and rearrangement of iron. In continuation of this subject, treated of in a short paper read before this Society last year*, the following communication records some further observations on those forms of ferruginous variation which appear to have been due to secondary causes, subsequent to original mechanical deposition. 1. Literature .—It may be convenient in the first place to give a short résumé of the previous geological and chemical papers that directly refer to, or bear on the subject. Sir Henry James, in a short paper dated May the 15th 1846, published in the ‘London, Edinburgh, and Dublin Philosophical Magazine’ for July 1843, notices that the disposition of the bluish-green discoloration of the Old and New Red Sandstones is independent of stratigraphical arrangement, and suggests that, as the light lines and blotches are generally adjacent to joints, the cause of the discharge of colour is due to infiltration. The author, in a note to this paper, also refers to an observation by Mr. Mallet, that “if through a fissure in a rock containing peroxide of iron a stream of water should pass containing an earthy sulphate and organic matter, the sulphate will be decomposed, and sulphuretted hydrogen evolved, which might reduce the peroxide of iron to a lower oxide.” With reference to this suggestion, I will here only observe that the presence of sulphate

This publication has 0 references indexed in Scilit: