during both ages, and the rapid increase of depth in the Atlantic to its west would allow of a considerable depression taking place, without altering in any important degree the position of the sea-margin.
Professor Heer[1] places his Atlantis to the south-west of the land represented in the map (Fig. 6); but the enormous depth of the North Atlantic renders it very improbable that there was dry land in that region at a time, geologically speaking, so recent as the Meiocene age.
The Mountains.
The principal mountains in the British Isles were in their present positions in the Meiocene age, but were considerably higher. If we take the rate of denudation to be the same as that which we know to have taken place in the volcano of Mull in post-Meiocene times (Fig. 7), which, exclusive of the cone, has been shown by Professor Judd[2] to have been 6000 feet high, while the present height of Beinn More, the highest fragment now remaining, is but 3172 feet, we arrive at the startling result that the height of the Meiocene mountains in Britain was double what it is now. It is therefore probable that in the western and northern parts of our island mountains rose to a height of 6000 or 7000 feet, even if we do not take into account the amount of elevation above the sea necessary to allow of continuity between Britain and Iceland. If the 500 fathoms of elevation of the Meiocene continent be added, the mountains must then have
