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the parts separated by the distance F E. At some later period the slide c was formed by a similar fracture and displacement, crossing both the copper vein and the tin vein, and shifting the parts of them both, so that the copper vein was divided into two parts, b and b′, separated by the interval A C; and the tin vein again divided and its parts a and a′ separated by the interval B D (which is equal to A C). At the same or some other time, the slide d produced a slighter effect on the tin vein a at G. What other effects may have accompanied the other intersections, which are indicated as possible, viz. c and d, b and d, the locality does not shew.

Finally, after all these fractures, three fissures in a north and south direction, x, y, z in the ground plan (not seen in the vertical section), have been formed across a, b, c, d, e, f, and have been accompanied by