In the meantime, I would have the reader to fix the stone-lily in his memory as peculiarly and emphatically a marine animal, dwelling probably in the deeper and stiller recesses of the ocean, like the Pentacrinite of existing times. Let him try to remember it, not in the broken and sorely mutilated state in which we find it among the blocks of our lime-quarries, but as it must have lived at the bottom of the carboniferous seas. The oozy floor of these old waters lay thickly covered with many a graceful production of the deep, submarine gardens of "Violet, asphodel, ivy, and vine-leaves, roses and lilies, Coral and sea-fan, and tangle, the blooms and the palms of the ocean." Amid this rich assemblage of animated forms, the stone-lilies must have occupied a conspicuous place. Grouped in thick-set though diminutive forests, these little creatures raised their waving stems, and spread out their tremulous arms, like beds of tulips swaying in the evening air. Their flower like cups, so delicately fringed, must have presented a scene of ceaseless activity as they opened and closed, coiling up while the animal seized its prey, or on the approach of danger, and relaxing again when the food had been secured, or when the symptoms of a coming enemy had passed away. Only from this animated action would one have been apt to conjecture these organisms to be other than vegetable. They lived, too, not in detached patches, like the tulip-beds of the florist, but, to judge from the abundance of their remains, must have covered acre after acre, and square mile 'after square mile, with a dense growth of living, quivering flowers. As one individual died out, another took its place, the decaying steins and flowers meanwhile falling to pieces among the limy sediment that lay thickly athwart the sea-bottom, and contributing, by their decay and entombment, to build up those enormous masses of rock, known as the mountain-limestone, which stretch through Yorkshire and the central counties into Wales. In addition to the stone-lilies, the carboniferous rocks contain the remains of several other kinds of _Echinodermata_. Some of them find their nearest modern analogues among the sea-urchins so common on our shores; but I pass on to notice another very interesting class of fossils known by the name of _Crustacea_, and still abundantly represented, the crab and lobster being familiar examples.