382 COAL OP MIOCENE PERIOD. 



mens 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.* 



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 Kaepfnach 

 near Horgen on the lake of Zurich, and of CEningen near 

 Constance. 



The Brown-coal at CEningen forms thin beds of little 



* At Ptitzberg 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 

 Ptitzberg, which was three yards in diameter, M. Noggerath 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 forma- 

 tion 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 tlie Brown-coal Formation near Bonn, and also with the Surturbrand of 

 Iceland, are found Beds that divide into Lamince 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. 



