currents, forests growing, decaying, and being buried, sand and chalk being deposited in layers, molten minerals thrown up by volcanoes, ice forming at a definite temperature, glaciers scoring the rocks, icebergs transporting boulders, rains and rivers slowly washing down the hills, and waves corroding the cliffs on the sea-shore. We have evidence also that life in many forms abounded. Those forms, though seldom transmitted to creatures of the present day with anything approaching an exact likeness, can yet be classified under the same general names with the most modern forms of life. Now sponges are forms of an extremely simple organization. The silicious spicules are well adapted for the wear and tear of a fossil existence. In the greensand and the chalk they are actually found in extraordinary abundance. It would be inconvenient upon any theory to have to suppose these very simple structures introduced into the world for the first time quite late in the series of living organisms, and after beings much more complicated and higher in the scale of existence, unless, indeed, we suppose that about the time of the Great Oolite the evolution of man was first thought of, and the sponge accordingly prepared for him to wash his face with. But even if the bath and the basin be admitted as the final causes of sponge-existence, the conception of it must be carried back, as we have seen, to the Silurian period; while, according to Mr. Parfitt, the immense interval of Lias and Trias, Permian, Carboniferous, and Devonian remains black and spongeless, as though it were the appropriate era of the great unwashed. But if the Darwinian theory be a true one, sponge-life having begun in the Silurian period, and being in existence now, must have been continuous through the whole interval; every single deposit in the entire series since the Silurian must have been contemporary with some of the sponges; and, as a matter of fact, Mr. Parfitt’s statement, however true of the condition of our knowledge a few years back, must now be qualified by the addition of several species spread over the interval in Britain alone, even if we exclude some indefinite structures, of which no opinion can be at present pronounced with safety. Mr. Parfitt himself, in a paper read at Honiton in 1868, remarks that ‘the Devonian formation has furnished a great number of specimens of what appear to be species of sponges.’ From Permian and Triassic beds on the continent of Europe, a very large number of forms are said to be more or less distinctly made out. Mr. Salter, in 1864, reported the discovery of Protospongia Fenestrata in the Lingula flags of St. David’s, thus carrying back this form of life beyond the Silurian to the Cambrian era. It is an interesting illustration of the great ambiguity of these ancient fossils, that two such authorities as Mr. Salter and Dr. Bowerbank differed about the Protospongia, the one supposing it to exhibit the spicules, the other the fibre of the sponge.