in the brick-earths are of extinct species--there are no species included in this latter category of precisely similar kinds to animals now living, Thus the elephant was different to modern elephants; we know, from remains found elsewhere, that it was clothed with wool. The same also with the rhinoceros. The reindeer no longer lives in this country, being confined to northerly latitudes; whilst the musk sheep is a denizen of the Arctic regions, and the hippopotamus is restricted to the tropical or sub-tropical climes. But we might continue for a long time expatiating on the character of the very numerous mammalian remains found in our common brick-earths. What a curious assemblage of animals! It is wonderful to contemplate the time when the reindeer and musk sheep lived side by side with the elephant and rhinoceros on the site whereon London now stands. That is not all, however. In the same brick-earths and gravels, tools (flint implements), fashioned by the hands of man, are also frequently discovered, and in one place at Crayford, the spot whereon flint implements were manufactured has been ’lighted upon. Each flake chipped off has been collected and pieced together, and the shape of the original flint has thus been determined. Clearly, from this evidence, the earth from which millions of bricks have been made has formed since primæval man (and with him the animals alluded to) inhabited the valleys of the Thames and its tributaries. It is interesting, too, to reflect on the circumstance that the materials upon which many of these facts of great philosophical significance are based, have been collected through the instrumentality of the workmen. Palæontologists are proud to acknowledge that; their debt of gratitude to the intelligent and persevering men can never be fully repaid. Pursuing the matter still further, we discover a quantity of shells, blanched and very frail--they seem to be deprived of much of their original substance, so to speak; their entombment in the brick-earth has taken all the natural colour out of them. Studying these, we soon ascertain that they belong to land snails and mollusca which inhabit fresh water. Living representatives of the same species are, with few exceptions, found in Kent and Essex.