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Show 180 ISLAND LIFE. (PART J. occurs also m. Sp1. tzbergen. Th e E uropea n deposits of the s. ame l l . th these in their general character, comfers, age c ose y agree Wl • h f the vegetation while cycads and ferns formmg t e mass o ' exoO'en' s are enti·r ely absent, t h e a b ove -named , Greenland poplar bei~O' the oldest known dicotyledonous plant.I It we take these facts as really representing the flora of the period, we shall be forced to conclude that, measured by the change effected in its plants, the lapse of time between the Lower and Upper Cretaceous deposits was far greater .than ~etween the Upper Cretaceous and the Miocene-a concluswn qmte opposed to the indications afforded by the mollusca and the higher animals of the two periods. It seems pro Hable, therefore, that these Lower Cretaceous plants represent local peculiarities of veO'etation such as now · sometimes occur in tropical countries. o: sandy or coralline islands in the Malay Archipelago there will often be found a vegetation consisting almost wholly of cycads, pandani, and palms, while a few miles off, on moderately elevated land, not a single specimen of either of these families may be seen, but a dense forest of dicotyledonous trees covering the whole country. A lowland vegetation, such as that above described, might be destroyed and its remains preserved by a slight depression, allowing it to be covered up by the detritus of some adjacent river, while not only would the subsidence of high land be a less frequent occurrence, but when it did occur the steep banks would be undermined by the_ waves, and the trees falling down would be floated away, and would either be cast on some distant shore or slowly decay on the surface or in the depths of the ocean. From the remarkable series of facts now briefly summarized, we learn, that whenever plant-remains have been discovered within the Arctic regions, either in .:C~rtiary or Cretaceous deposits, they show that the climate was· one capable of supporting a rich vegetation of trees, shrubs, and herbaceous plants, similar in general character to that which prevailed in the temperate zone at the same periods, but sh~wing the influence of a less congenial climate. These deposits belong to at least four 1 The preceding account is mostly derived from Professor Heer's great work Flora Fos.silis A rctica. OHAI'. IX.] MILD ARCTIC CLIMATES. J 81 distinct geological horizons, and have been found widely scattered within the Arctic circle, yet nowhere has any proof been obtained of intercalated cold periods, such as would be indicated by the remains of a stunted vegetation, or a molluscan fauna similar to that which now prevails there. Stratigraphical Evidence of long-continr~.wd mild Arctic conditions.- Let us now turn to the stratigraphical evidence, which, as we have already shown: offers a crucial test of the occurrence or non-occurrence of glaciation during any extensive geological period ; and here we have the testimony of perhaps the greatest living authority on Arctic geology-Professor Nordenskjold. In his lecture on "The Former Climate of the Polar Regions" he says : " The character of the coasts in the Arctic regions is especially favourable to geological investigations. While the valleys are for the most part filled with ice, the sides of the mountains in summer, even in the 80th degree of latitude, and to a height of 1,000 or 1,500 feet above the level of the sea, are almost wholly free from snow. Nor are the rocks covered with any amount of vegetation worth mentioning; and, moreover, the sides of the mountains on the shore itself frequently present perpendicular sections, which everywhere expose their bare surfaces to the investigator. The knowledge of a mountain's geognostic character, at which one, in the more southerly countries, can only arrive after long and laborious researches, removal of soil and the like, is here gained almost at the first glance; and as we have never seen in Spitzbergen nor in Greenland, in these sections often many miles in length, and including one may say all formations from the Silurian to the Tertiary, any boulders even as large as a child's head, there is not the smallest probability that strata of any considerable extent, containing boulders, are to be found in the polar tracts previous to the middle of the Tertiary period. Since, then, both an ex amination of the geognostic condition, and an investigation of the fossil flora and fauna of the polar lands, show no signs of a glacial era having existed in those parts before the termination of the Miocene period, we are fully justified in rejecting, on the evidence of actual observation, the hypotheses founded on purely theoretical speculations, which assume the many times |