(Everywhere these Miocene islands, etc., bear a flora of true type.) If this land existed, it did not extend to America, for the fossils of the Miocene of America are representative and not identical.

Where, then, was the edge or coast-line of it, Atlantic-wards?
Look at the form and constancy of the great fucus-bank, and consider that it is a Sargassum bank, and that the Sargassum there is in an abnormal condition, and that the species of this genus of fuci are essentially ground-growers, and then see the probability of this bank having originated on a line of ancient coast.
Now, having thus argued independently, first on my flora and second on the geological evidences of land in the quarter required, I put the two together to bear up my Irish case.
I cannot admit the Sargassum case to be parallel with that of Confervae or Oscillatoria.
I think I have evidence from the fossils of the boulder formations in Ireland that if such Miocene land existed it must have been broken up or partially broken up at the epoch of the glacial or boulder period.
All objections thankfully received.
Ever most sincerely, EDWARD FORBES.
LETTER 21.

TO L.JENYNS (BLOMEFIELD).

Down.

[1846].
I am much obliged for your note and kind intended present of your volume.