70 THE PRESERVATION OF PLANTS AS FOSSILS. [CH. 



rock occurs near Suzanne in Southern France, and is of Eocene 

 age\ The plants were probably blown on to the freshly de- 

 posited carbonate of lime, or they may have simply fallen from 

 the tree on to the incrusting matrix ; more material was after- 

 wards deposited and the flowers were completely enclosed. 

 Eventually the plant substance decayed, and as the matrix 

 hardened moulds were left of the vegetable fragments. Wax 

 was artificially forced into these cavities and the surrounding 

 substance removed by the action of an acid, and thus perfect 

 casts were obtained of Tertiary flowers. 



Darwin has described the preservation of trees in Van 

 Diemen's land by means of calcareous substances. In speaking 

 of beds of blown sand containing branches and roots of trees 

 he says: 



"The whole became consolidated by the percolation of calcareous 

 matter ; and the cylindrical cavities left by the decaying of the wood were 

 thus also filled up with a hard pseudo-stalactitical stone. The weather is 

 now wearing away the softer parts, and in consequence the hard casts of 

 the roots and branches of the trees project above the surface, and, in a 

 singularly deceptive manner, resemble the stumps of a dead thicket 2." 



As a somewhat analogous method of preservation to that 

 in travertine, the occurrence of plants in amber should be 

 mentioned. In Eocene times there existed over a region, part 

 of which is now the North-east German coast, an extensive 

 forest of conifers and other trees. Some of the conifers were 

 rich in resinous secretions which were poured out from 

 wounded surfaces or from scars left by falling branches. As 

 these flowed as a sticky mass over the stem or collected on 

 the ground, flowers, leaves, and twigs blown by the wind or 

 falling from the trees, became embedded in the exuded resin. 

 Evaporation gradually hardened the resinous substance until 

 the plant fragments became sealed up in a mass of amber, 

 in precisely the same manner in which objects are artificially 

 preserved in Canada balsam. In many cases the amber acts as 

 a petrifying agent, and by penetrating the tissues of a piece of 

 wood it preserves the minute structural details in wonderful 



1 Saporta (68). 2 Darwin (90) p. 432. 



