XVI. The Barite Veins of South-West Scotland

Abstract

Barite is by no means a rare mineral in this part of the country, where it occurs in veins sometimes thin, but usually of more or less width, one grand example broadening out in parts to as much as 20 feet. So far as I know it is never found in beds interstratified with sedimentary rocks, but always in veins more or less vertical, and not confined to any particular rock, but intersecting igneous and stratified ones impartially. Occasionally it is got in a crystalline form in drusy cavities along with other minerals, and in the interior of fossil shells. Of the rocks in which barite is here found the oldest belong to the Llandeilo division of the Silurian formation, as it is abundant in the mineral veins of Leadhills and Wanlockhead, Lanarkshire. I am not aware that it is present alone in these veins, though, of course, there are, strictly speaking, no veins of pure barite. In the rocks seen in the lower part of Glen Sannox, Arran, and which probably belong to the Old Red Sandstone, barite veins occur. There are considerable veins of it in the Ayrshire Calciferous Sandstone, and smaller ones in the overlying traps. It is present in this same trap in Renfrewshire, the position being between the Calciferous Sandstone and the Lower Limestone series. In the latter rocks barite is found only sparingly in thin veins, and sometimes in crystallised form in the cavities of fossils. This is the highest horizon in which it This 250-word extract was created in the absence of an abstract