In this paper the author, describes 1st, the geological position of the gypsum deposits. The gypsum beds of Nova Scotia all belong to the carboniferous system. No gypsum occurs in older formations, and in the overlying new red, only slender veins and small nodules are found. The gypsum characterises the lower members of the carboniferous series, underlying the productive coal measures. The associated rocks are red sandstones and clays, with very few fossil plants, and thick beds of limestone abounding in marine shells. In the only well ascertained instance of gypsum occurring above the coal measures, it is accompanied by limestone with some of the same shells. The gypsum forms regular conformable beds sometimes 100 feet thick. They are much fractured and difficult to trace from the wooded state of the country; but one thick bed was traced by the author for ten miles.