tion of the regular metalliferous veins is about east and west, and that in some districts, the same vein is known actually to pass through several mines, it occurred to me, as being within possibility, that at least some veins might extend the whole length of the county; and that if the situations of such mines as were then working, or had lately been worked, were accurately described on a map, it might throw some light on the idea. With this view therefore, after visiting many of the mines, particularly those of the mining district of which Redruth may be said to be the centre, that object was accomplished by the assistance of some friends. The result by no means confirmed the idea in which it originated: for although it evinced that in the year 1800 there were about 120 mines in the county, either then working, or which had lately been worked, few of the east and west or metalliferous veins, from causes that will be explained in the following pages, have been explored, or even satisfactorily traced more than two or three miles. The map was however preserved merely with a view to private gratification; but several gentlemen, whose zeal for geological inquiry induced them to consider this attempt to shew the localities of mines as in some degree worthy of attention, urged my offering it to the notice of the Geological Society, accompanied by a memoir on the subject of the Veins of Cornwall.
The map not being of course adapted to the present state of the mines, nor even sufficiently exact in regard to their several localities at the time at which it was compiled, to meet the public eye, its publication is laid aside for the present, not however without expecta-