The Vigra Gold Mines, North Wales: the Crushing Mill, 1862. The Vigra gold mines are situated in a most picturesque and mountainous range in the parish of Llanabar, on the north of the navigable River Mowddach...in the county of Merioneth. The geological features of this district are the Cambrian rocks, overlaid by the lower Silurian lingula flags. These rocks are coarse, greenish- grey grits. The lingula flags are chiefly slatey beds, more or less arenaceous, and interstratified with courses of sandstone. Both the Cambrians and Silurians are frequently penetrated by light grey calcareous and ordinary greenstone dykes, some of which are magnetic. In the Cambrian sandstone these dykes appear to run in all directions, the general direction being rather across the strike. In the silurian region the direction of the dykes is generally parallel with the lines of bedding. The Vigra mine is situated entirely in the lingula flags...the...water-wheel, which is about 60ft. in diameter, works a powerful Cornish crushing-machine capable of crushing forty tons of ore daily. The wheel is supplied with water from the charming little river called the Hirgwm. At the present time this mine is yielding upwards of fifteen pounds weight of gold per week. From "Illustrated London News", 1862.