The abstract from the book by academician N.Ozeretskovsky
Travelling by Ladoga and Onego lakes
...To this side I went by water from Serdobol steering close to the shore.
In 5 leagues from Serdobol close to the shore there lieth a small isle Uven, some 45 fathoms long and 30 fathoms wide. They quarry there gray bluish marble with white, yellow, greenish and black patches and spurts. It is quarried at more than a fathom deeper than water level, the latter been constantly pumped out, but these worries are paid back by the convenience of loading cargo, as galley-boats can come straight to the isle and take the marble onboard. Both Uven and Ruskeala marbles show blinking veins of ferreous pyrites.
A league from Uven, on the other side of Serdobol bay close to the shore there is Tulola Island, having the circumference of 1.5 leagues and they quarry there the bluish granite used in St-Petersburg for gorgeous state buildings. The granite there found not in boulders but as flowing strata and rather a high island fully consisting of it is quite convenient for quarrying, as there is no water problems. The galley-boats come straight to the island and take cargo of rough-hewed granite.
At the night of July 12-th 1785, while I was passing Uven Island, a tremendous storm-cloud appeared with heavy rain, terrific thunders and horrible lightnings and for an hour was passing the place were stood my tiny vessel. It seamed to me that from tremendous lightnings the very mountains will catch fire and from horrible thunders the very entrails of them will bust open. Such powerful storms I experienced several times in mountainous places that seem to attract storm-clouds and protect settelments that lie between them.
On the mainland opposite Uven Island there is a house for quarry supervisor that cometh here from time to time from Ruskeala. There is a small village also called Uven around a mile from that house. And close to is a mouth of Lyaskilya river, that hath a five fathoms fall some two leagues up the stream. The water strength there is so great, especially at springtime, that sometimes water carrieth the rather big stones from the edge of the fall.
At that village I had seen very special use of pig's bristle. A killed pig is scalded with boiling water and bristle is shred off. The shredded bristle is dealt as if it was fleece, spanned and from resulting thick treads cords that used for nets framings are twisted. Such cords do not rot from wetness and serve substantially longer than hempen ones.