Note 149 — Chapter VI
Reading edition
Since the above passage was first printed in a former edition, June, 1835, it has been shown by the observations of Sir R. Murchison, M. de Verneuil, and Count Keyserling, and more recently by M. Middendorf (see above, p. 81), that the Lowland of Siberia has actually been extended, since the existing species of shells inhabited the northern seas.