STRATIGRAPHICAL GEOLOGY. 5 of the Cretaceous epoch, a vast period. The dominant vertebrata were Reptilia, with many genera of Teleostian Fishes. VI. Tertiary Age, or Age of Mammals. 1 —The Tertiary age is characterised by the presence of Mammalia in nearly all its subdivi sions. The Pliocene period is individualised by the remains of ceta cean mammalia, many of which may have been derived from the older Miocene series. The more recent deposits (post-Pliocene) con tain a large number of genera belonging to the Pachydermata, Carnivora, Rodentia, and Ruminantia. Mammals began (so far as we know) in the Reptilian age, and the Marsupialia were the highest race of this Sixth age. VII. Quaternary, or Age of Man— Subdivisions of Geological time :— L ARCHAN Time, including an Azoic and an Eozoic era, though not yet distinguished in the rocks— I. Azoic Age. 2. Eozoic Age. II. Paleozoic Time— i. The Age of Invertebrates, or Silurian. 2. The Age of Fishes, or Devonian. 3. The Age of Coal-plants, or Carboniferous. III. Mesozoic Time— The Age of Reptiles. IV. Cainozoic Time— 1. The Tertiary, or Age of Mammals. 2. The Quaternary, or Age of Man. (Dana.) The annexed diagram broadly illustrates the progress of life through all the Seven Ages. 1. Age of Man (Quaternary). 2. Age of Mammals (Tertiary). 3. Age of Reptilia (Secondary). 4. Carboniferous Age. 5. Age of Fishes (Devonian). 6. Age of Tnverte brata (Silurian). 7. Arch ?ean Time. 1 See Gaudry, “ Les Enchainements du Monde Animal dans les temps Golo giques-Mammifdres Tertiaires." Paris, 1878.