Page:Geology and Mineralogy considered with reference to Natural Theology, 1837, volume 1.djvu/386

 382 found by Mr. Horner in the Brown-coal near Bonn (See Ann. Phil. Lond. Sept. 1833, V. 3, 222,) leaves closely allied to the Cinnamomum of our modern tropics, and to the Podocarpus of the southern hemisphere. At Pützberg near Bonn, six or seven beds of Brown-coal alternate with beds of sandy clay and plastic clay. The trees in the Brown coal are not all parallel to the planes of the strata, but cross one another in all directions, like the drifted trees now accumulated in the alluvial plains, and Delta of the Mississippi; (see Lyell's Geology, 3d. edit. vol. i. p. 272.) some of them are occasionally forced even into a vertical position. In one vertical tree at Pützberg, which was three yards in diameter, M. Nöggerath counted 792 concentric rings. In these rings we have a chronometer, which registers the lapse of nearly eight centuries, in that early portion of the Tertiary period which gave birth to the forests, that supplied materials for the formation of the Brown-coal.

The fact mentioned by Faujas that neither roots, branches, or leaves are found attached to the trunks of trees in the Lignite at Bruhl and Liblar near Cologne, seems to show that these trees did not grow on the spot, and that their more perishable parts have been lost during their transport from a distance.

In the Brown-coal Formation near Bonn, and also with the Surturbrand of Iceland, are found Beds that divide into Laminae as thin as paper (Papier Kohle) and are composed entirely of a congeries of many kinds of leaves. Henderson mentions the leaves of two species of Poplar, resembling the P. tremula and P. balsamifera, and a Pine, resembling the Pinus abies as occurring in the Surturbrand of Iceland.

Although we have followed Brongniart in referring the deposites here enumerated to the first, or Eocene period of the Tertiary series, it is not improbable that some of them may be the products of a latter era, in the Miocene or Pliocene periods. Future observations on the Species of their animal and vegetable remains will decide the exact place of each, in the grand Series of the Tertiary formations.

In the Molasse of Switzerland, there are many similar deposites affording sometimes Coal of considerable purity formed during the second, or Miocene period of this series, and usually containing fresh water shells. Such are the Lignites of Vernier near Geneva, of Paudex and Moudon near Lausanne, of St. Saphorin near Vevay, of Kæpfnach near Horgen on the lake of Zurich, and of Œningen near Constance.

The Brown-coal at Uiningen forms thin beds of little