FLORA OF THE TERTIARY PERIOD IN EUROPE. 757 



The Pliocene flora has 258 species, of which 226 belong to Algae, 

 Fungi, Musoi, Filices, Palmse, Ericaceae, Aquifoliaceae, Aceracese, 

 Ulmaceae, Eharanacese, Papilionaceae, Juglandacese, Salicaceae, Quer- 

 cinese, Betulaceae, Taxaceae, Cupressineae, and Abietineae. The Eocene 

 species are included in genera which iDelong at the present day to 

 inter-tropical regions, comprising in them India and the Asiatic islands 

 of Australia. Some are peculiar to the Mediterranean region. The 

 aquatic plants, which form almost one^thiid of the flora, belong to 

 genera now peculiar to the temperate regions of Europe and of North 

 America, or occurring everywhere. The Miocene species belong to 

 genera, of which several are found in India, tropical America, and the 

 other inter-tropical regions, but which for the most part inhabit the 

 sub-tropical and temperate regions, including the United States. Some 

 of the genera are peculiar to the temperate regions. The aquatic 

 genera, poor in species, occur everywhere, or else solely in the temper- 

 ate regions. The Pliocene species belong to genera which almost all 

 inhabit the temperate regions either of the old continent or of the 

 United States. A few only are of genera existing in India, Japan, 

 and the north of Africa. These various floras, which present succes- 

 sively the character of those of inter-tropical, sub-tropical, and tem- 

 perate regions, seem to indicate that central Europe has, since the 

 •commencement of the Tertiary period, been subjected, during the suc- 

 cession of time, to the influence of these three different temperatures. 

 It would appear, then, Kaulin remarks, that the climate of Europe 

 has during the Tertiary period gradually become more temperate. 

 This may proceed either from a displacement of the earth's axis, or 

 from the gradual cooling of the earth, or from a different proportion 

 of land and water. 



Brown coal occurs in the upper Tertiary beds, and in it vegetable 

 structure is easily seen under the microscope. Goeppert, on examin- 

 ing the brown coal deposits of northern Germany and the Ehine, 

 flnds that Coniferae predominate in a remarkable degree. Among 300 

 specimens of bituminous wood collected in the Silesian brown coal 

 deposits alone, only a very few other kinds of Exogenous wood occur. 

 This seems remarkable, inasmuch as in the clays of the brown coal 

 formation in many other places leaves of deciduous Dicotyledonous 

 trees have been found ; and yet the stems on which we may suppose 

 them to have grown are wanting. The leaves have been floated away 

 from the place where they grew by a current of water, which was not 

 powerful enough to transport the stems. The coniferous plants of 

 these brown coal deposits belong to Taxineae and Cupressineae chiefly. 

 Among the plants are Pinites protolarix and Taxites Ayckii. Many 

 Coniferae exhibit highly compressed very narrow annual rings, such 

 as occur in those of northern latitudes. Goeppert has described a 

 trunk, or rather the lower end of a trunk, of Pinites protolarix, dis- 



