Page:Transactions of the Geological Society, 1st series, vol. 2.djvu/161

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151
Mr. William Phillips on the Veins of Cornwall.

That of the flucans, which consisted, when in the schist, of two veins of flucan or soft marl with portions of schist between them, were while in the elvan very much smaller, and their substance appeared to be either a mere seam of flucan, or was of a sandy nature resembling pulverized porphyry.

The metalliferous veins likewise passed through the channel of porphyry, which had no other effect upon them than that of diminishing the load in size; it therefore appeared to be richer.

The north and south vein, called Convocation Cross Course, was not found to produce any silver in this mine.

Section of the Miner Old Vein.

Transactions of the Geological Society, 1st series, vol. 2 figure page 0592 fig. 11.png

This section is on the course of the vein called the Manor Old Vein, on the ground plan of Herland and Drannack mines. It was originally worked as a separate mine, under the name of Herland. Its greatest depth was about 150 fathoms from the surface.

The several cross courses and flucans correspond with those in the ground plan. Halfpenny Little Flucan and Chambers's Flucan, were nearly, if not quite, perpendicular to the horizon; the underlie of the others will be seen. It will be observed on consulting the ground plan, that Williams's or Penberthie's flucan traversed the veins both of this mine and that of Pleasure, Fancy, and North Herland mines. North and South veins generally take the name of the shaft they most nearly approach. The flucan in this mine was nearest to a shaft called Williams's, and therefore obtained the name of Williams's flucan. In the other, it approached nearest to Penberthie's shaft, and was therefore called Penberthie's flucan. Both names are therefore given on the ground plan.