unfolds a beautiful gradation of being, from the corals, molluscs, and simple crustacea of the grauwacke—the enamelled fishes, crinoidea, and cryptogamic plants of the lower secondary—the chambered shells, sauroid reptiles, and marsupial mammalia of the upper secondary—up to the true dicotyledonous trees, birds, and gigantic quadrupeds of the tertiary epoch. The student must not, however, suppose that the fossils of this era bring him up to the present point of organic nature, for thousands of species which then lived and flourished became in their turn extinct, and were succeeded by others long before man was placed on the earth as the head of animated existence. Of _Plants_, few marine species have been detected; but the fresh-water beds have yielded cycadeæ, coniferae, palms, willows, elms, and other species, exhibiting the true dicotyledonous structure. Nuts allied to those of the cocoa and other palms have been discovered in the London clay; and seeds of the fresh-water _characeæ_, or stoneworts, known by the name of _gyrgonites_ (Gr., _gyros_, curved, and _gonos_, seed), are common in the same deposit. Of the _Radiata_, _Articulata_, and _Mollusca_, so many belong to existing genera, that this circumstance has suggested the classification of tertiary rocks according to the number of recent species which they contain.”—_Chambers’ Outlines_, p. 147. Let us now begin _the Eocene period_. The most remarkable formations of this period are the London and Hampshire basins. Of the London basin we have already spoken in a previous chapter; a few additional remarks will be sufficient. The diagrams 4 and 5, p. 25, will explain these tertiary deposits better than any verbal explanation; and when it is remembered that this bed of clay is probably a thousand feet in thickness, we get a passing illustration of the folly of those puerile reports which a few years since were industriously circulated about a coming earthquake in London. Poor, uneducated people took up the alarm rather anxiously, never dreaming of what any tyro in science would have told them—that supposing there was a subterranean chimney on fire down below, there was a wet blanket under their feet composed of a thousand feet of sodden and solid clay, a blanket of the material they may see in the deep cuttings of the Great Northern Railway in and about London, that would most effectually have put out any fire, or checked the progress of any earthquake, just as a cannon-ball is stopped dead by a woolsack.