'The fact of the forms of life changing simultaneously, in the above large sense, at distant parts of the world, has greatly struck those admirable observers, MM. de Verneuil and d'Archiac. After referring to the parallelism of the palæozoic forms of life in various parts of Europe, they add, "If struck by this strange sequence, we turn our attention to North America, and there discover a series of analogous phenomena, it will appear certain that all these modifications of species, their extinction, and the introduction of new ones, cannot be owing to mere changes in marine currents, or other causes more or less local and temporary, but depend on general laws which govern the whole animal kingdom." M. Barrande has made forcible remarks to precisely the same effect. It is indeed quite futile to look to changes of currents, climate, or physical conditions, as the cause of these great mutations in the forms of life throughout the world, under the most different climates.' Mr. Darwin holds that 'looking to a remotely future epoch,' the later tertiaries, namely, 'the upper pliocene, the pleistocene and strictly modern beds of Europe, North and South America, and Australia, from containing fossil remains, in some degree allied, from not including those forms which are only found in the older under-lying deposits, would be correctly ranked as simultaneous, in a geological sense.' These statements afford, we think, a sufficient basis for the general scheme of Mosaic geology which we are considering; and it may be remarked that the latest of the geological epochs of simultaneity, as defined by Mr. Darwin, would agree indifferently well with the last of the Mosaic days or periods, as defined by Hugh Miller.