of Thujopsis and Salisburia, now peculiar to Japan.  There are also beeches, oaks, planes, poplars, maples, walnuts, limes, and even a magnolia, two cones of which have recently been obtained, proving that this splendid evergreen not only lived but ripened its fruit within the Arctic circle.  Many of the limes, planes, and oaks were large-leaved species; and both flowers and fruits, besides immense quantities of leaves, are in many cases preserved.  Among the shrubs are many evergreens, as Andromeda, and two extinct genera, Daphnogene and M’Clintockia, with fine leathery leaves, together with hazel, blackthorn, holly, logwood, and hawthorn.  A species of Zamia (Zimites) grew in the swamps, with Potamogeton, Sparganium, and Menyanthes; while ivy and villes twined around the forest-trees, and broad-leaved ferns grew beneath their shade.  Even in Spitzbergen, as far north as lat. 78 deg. 56’, no less than ninety-five species of fossil plants have been obtained, including Taxodium of two species, hazel, poplar, alder, beech, plane-tree, and lime.  Such a vigorous growth of trees within 12 deg. of the pole, where now a dwarf willow and a few herbaceous plants form the only vegetation, and where the ground is covered with almost perpetual snow and ice, is truly remarkable.”

Taking the Miocene flora as a whole, Dr Heer concludes from his study of about 3000 plants contained in the European Miocene alone, that the Miocene plants indicate tropical or sub-tropical conditions, but that there is a striking inter-mixture of forms which are at present found in countries widely removed from one another.  It is impossible to state with certainty how many of the Miocene plants belong to existing species, but it appears that the larger number are extinct.  According to Heer, the American types of plants are most largely represented in the Miocene flora, next those of Europe and Asia, next those of Africa, and lastly those of Australia.  Upon the whole, however, the Miocene flora of Europe is mostly nearly allied to the plants which we now find inhabiting the warmer parts of the United States; and this has led to the suggestion that in Miocene times the Atlantic Ocean was dry land, and that a migration of American plants to Europe was thus permitted.  This view is borne out by the fact that the Miocene plants of Europe are most nearly allied to the living plants of the eastern or Atlantic seaboard of the United States, and also by the occurrence of a rich Miocene flora in Greenland.  As regards Greenland, Dr Heer has determined that the Miocene plants indicate a temperate climate in that country, with a mean annual temperature at least 30 deg. warmer than it is at present.

The present limit of trees is the isothermal which gives the mean temperature of 500 Fahr. in July, or about the parallel of 67 deg.  N. latitude.  In Miocene times, however, the Limes, Cypresses, and Plane-trees reach the 79th degree of latitude, and the Pines and Poplars must have ranged even further north than this.