"Bischoff, however, advances the suggestion that, as the shaft may have been sunk in search of calamine, and not for the working of the lead, the age of the bones would not be so great as might at first be assumed. An analysis of the few crystals placed at my disposal leads to the conclusion that their constitution may be represented by the formula 3FeO.P²O⁵ + Fe²O³.P²O⁵ + 15 aq. "They belong to the monoclinic system of crystallography, and are of greenish-blue colour, becoming darker gradually on exposure to air." In several places, when digging below the level of the log pavement and thrusting a staff a few feet downwards, gas bubbled up through the water, which, on applying a lighted match, ignited with considerable explosion. This, on analysis, was found to be carburetted hydrogen or marsh gas, with a small quantity of carbonic acid gas. Before the stuff inside the circular trench was completely cleared away down to the level of the log pavement, our operations had to be abandoned on account of the severity of the weather. Meantime I drew up the above report from a careful journal kept of each day's proceedings and finds, and at the March meeting communicated it to the Society of Antiquaries of Scotland. But, notwithstanding the great variety of relics discovered, and the important information regarding the general structure of the crannog which had been ascertained, there were still several points requiring further elucidation. Of these the following four were the chief, which may be thus succinctly stated:-- _Firstly._--From a perusal of the Plan (Plate II.) it will be observed that at the south side there is at least one well-marked circular group of upright piles external to the one surrounding the log pavement; hence the question which pressed for solution was--Whether these groups merged into the one on the north side, or whether there was another corresponding to the former still further out? _Secondly._--It was obvious that the island extended considerably beyond our original circular trench, so that a correct estimate of it could not be formed from our present data. _Thirdly._--We had no reliable information regarding the composition of the island below the log pavement, as deeper digging could not be carried on to any extent without a pump, owing to the accumulation of water--the main drain being nearly on a level with it. _Fourthly._--The supposed gangway had to be examined. * * * * *