inferences legitimately deducible from it. [Illustration: Fig. 5. OLDHAMIA ANTIQUA;--the oldest known Zoophyte. Wrae Head, Ireland.] [Illustration: Fig. 6. PALÆOCHORDA MINOR. (One half nat. size.)] Beginning with the plants, let us, however, remark, that they do not precede in the order of their appearance the humbler animals. No more ancient organism than the _Oldhamia_ of the Lowest Irish Silurians, a plant-like zoophyte somewhat resembling our modern sertularia, has yet been detected by the geologist; though only a few months ago the researches of Mr. Salter in the ancient rocks of the Longmynd, Shropshire, previously deemed unfossiliferous, have given, to it what seem to be contemporary vegetable organisms, in a few ill-preserved fucoids. So far as is yet known, plants and animals appear together. The long upward march of the animal kingdom takes its departure at its starting point from a thick forest of algæ. In Bohemia, in Norway, in Sweden, in the British Islands, in North America, wherever, in fine, what appears to be the lowest, or at least one of the lowest, zones of life has yet been detected, the rocks are found to be darkened by the remains of algæ, so abundantly developed in some cases, that they compose, as in the ancient Lower Silurians of Dumfriesshire, impure beds of anthracite several feet in thickness. Apparently, from the original looseness of their texture, the individual plants are but indifferently preserved; nor can we expect that organisms so ancient should exhibit any _very_ close resemblance to the plants which darken the half-tide rocks and skerries of our coasts at the present time. We do detect, however, in some of these primordial fossils, at least a noticeable likeness to families familiar to the modern algæologist. The cord-like plant, _Chorda filum_, known to our children as "dead men's ropes," from its proving fatal at times to the too adventurous swimmer who gets entangled in its thick wreaths, had a Lower Silurian representative, known to the Palæontologist as the _Palæochorda_, or ancient chorda, which existed apparently in two species,--a larger and smaller. The still better known _Chondrus crispus_, the Irish moss or carrageen of our cookery-books, has likewise its apparent though more distant representative in _Chondritis_, a Lower Silurian algæ, of which there seems to exist at least three species. The fucoids, or kelp weeds, appear to have had also their representatives in such plants as _Fucoides gracilis_ of the Lower Silurians of the Malverns; in short, the Thallogens of the first ages of vegetable life seem to have resembled, in the group, and in at least their more prominent features, the algæ of the existing time. And with the first indications of land we pass direct from the Thallogens to the Acrogens,--from the sea weeds to the fern allies. The Lycopodiaceæ;, or club mosses, bear in the axils of their leaves minute circular cases, which form the receptacles of their spore-like seeds.