2. On New Species of Marine Diatomaceæ from the Firth of Clyde and Loch Fine. Illustrated by numerous drawings, and by enlarged figures, all drawn by Dr Greville

Extract

In two papers, read before this Society, and subsequently published in the Microscopical Journal, I described and figured a large number of new species of Diatoms, chiefly marine, which I had found in the Glenshira sand.

This sand was deposited by the Dhu Loch of Glenshira, at a period geologically recent, when that lake occupied a higher level than it now does, and extended about two miles farther up the valley. That the Dhu Loch at that period, as well as now, communicated with Loch Fine, so that at high tide the salt water flowed into the lakes, while at low water the current, as in a tidal estuary, flowed outwards, is proved by the fact, that the sand then deposited contains more marine than fresh-water species.