Ben Nevis the summit only to find "fragments of earthen and glass ware, chicken bones, corks, and bits of paper". It was not until 1847 that Ben Nevis was confirmed by the Ordnance Survey as the highest mountain in Britain and Ireland, ahead of its rival Ben Macdhui. The summit observatory was built in the summer of 1883, and would remain in operation for 21 years. The first path to the summit was built at the same time as the observatory and was designed to allow ponies to carry up supplies, with a maximum gradient of one in five. The opening of
Ben Nevis t-Suidhe (), is further west, forming a saddle with Ben Nevis which contains a small loch, Lochan Meall an t-Suidhe. The popular tourist path from Glen Nevis skirts the side of this hill before ascending Ben Nevis's broad western flank. Ben Nevis is all that remains of a Devonian volcano that met a cataclysmic end in the Carboniferous period around 350 million years ago. Evidence near the summit shows light-coloured granite (which had cooled in subterranean chambers several kilometres beneath the surface) lies among dark basaltic lavas (that form only on the surface). The two lying side-by-side is evidence the