According to the most recent views of high authorities, certain deposits—­such as the so-called “Bridlington Crag” of Yorkshire, and the “Chillesford beds” of Suffolk—­are to be also included in the Newer Pliocene, upon the ground that they contain a small proportion of extinct shells.  Our knowledge, however, of the existing Molluscan fauna, is still so far incomplete, that it may reasonably be doubted if these supposed extinct forms have actually made their final disappearance, whilst the strata in question have a strong natural connection with the “Glacial deposits,” as shown by the number of Arctic Mollusca which they contain.  Here, therefore, these beds will be included in the Post-Pliocene series, in spite of the fact that some of their species of shells are not known to exist at the present day.

The following are the more important Pliocene deposits which have been hitherto recognised out of Britain:—­

1.  In the neighbourhood of Antwerp occur certain “crags,” which are the equivalent of the White and Red Crag in part.  The lowest of these contains less than 50 per cent, and the highest 60 per cent, of existing species of shells, the remainder being extinct.

2.  Bordering the chain of the Apennines, in Italy, on both sides is a series of low hills made up of Tertiary strata, which are known as the Sub-Apennine beds.  Part of these is of Miocene age, part is Older Pliocene, and a portion is Newer Pliocene.  The Older Pliocene portion of the Sub-Apennines consists of blue or brown marls, which sometimes attain a thickness of 2000 feet.

3.  In the valley of the Arno, above Florence, are both Older and Newer Pliocene strata.  The former consist of blue clays and lignites, with an abundance of plants.  The latter consist of sands and conglomerates, with remains of large Carnivorous Mammals, Mastodon, Elephant, Rhinoceros, Hippopotamus, &c.

4.  In Sicily, Newer Pliocene strata are probably more largely developed than anywhere else in the world, rising sometimes to a height of 3000 feet above the sea.  The series consists of clays, marls, sands, and conglomerates, capped by a compact limestone, which attains a thickness of from 700 to 800 feet.  The fossils of these beds belong almost entirely to living species, one of the commonest being the Great Scallop of the Mediterranean (Pecten Jacoboeus).

5.  Occupying an extensive area round the Caspian, Aral, and Azof Seas, are Pliocene deposits known as the “Aralo-Caspian” beds.  The fossils in these beds are partly freshwater, partly marine, and partly intermediate in character, and they are in great part identical with species now inhabiting the Caspian.  The entire formation appears to indicate the former existence of a great sheet of brackish water, forming an inland sea, like the Caspian, but as large as, or larger than, the Mediterranean.