A new locality for manganese

Abstract

The district of Clava, in which the subject of this note was found, is full of interest to a geologist. The river Nairn, except at its source, flows over Old Red Sandstone, and in several places exposes fossiliferous shale containing fish remains. Several well-defined junctions between the Old Red Sandstone and the Gneiss are to be seen in the burns that enter the Nairn from the south. It is in one of these streams—Dalroy Burn— and at one of these junctions that the manganese-bearing rock was found. Before giving details of the find it may be interesting to describe the geological features of the burn. About two miles from its confluence with, the Nairn river, the Dalroy burn has cut for itself a V-shaped channel through boulder clay, at some places 130 feet deep. The top of the clay is 1000 feet above sea-level. The clay is of a light sandy colour and full of boulders of various sizes. It looks newer than the clay further down the burn. After leaving the clay, a dark, chocolate-coloured rock appears in close proximity to the Old Red Sandstone conglomerate. Close to this the stream plunges into a deep, tortuous, and narrow channel in the Old Red Sandstone conglomerate, from which it emerges into an open level space where a light-coloured sandstone crops up. On this flat another exposure of boulder clay appears. This clay looks older than that already mentioned, and contains many finely striated stones. At the bridge spanning the burn