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CHAPTER lY. 



THE PRESERVATION OF PLANTS AS FOSSILS. 



" The things, we know, are neither rich nor rare, 

 But wonder how the devil they got there." 



Pope, Prologue to the Satires. 



The discovery of a fossil, whether as an impression on the 

 surface of a slab of rock or as a piece of petrified wood, 

 naturally leads us back to the living plant, and invites specu- 

 lation as to the circumstances which led to the preservation 

 of the plant fragment. There is a certain fascination in 

 endeavouring, with more or less success, to picture the exact 

 conditions which obtained when the leaf or stem was carried 

 along by running water and finally sealed up in a sedimentary 

 matrix. Attempts to answer the question — How came the 

 plant remains to be preserved as fossils ? — are not merely of 

 abstract interest appealing to the imagination, but are of 

 considerable importance in the correct interpretation of the 

 facts which are to be gleaned from the records of plant-bearing 

 strata. 



Before describing any specific examples of the commoner 

 methods of fossilisation ; we shall do well to briefly consider 

 how plants are now supplying material for the fossils of a 

 future age. In the great majority of cases, an appreciation 

 of the conditions of sedimentation, and of the varied circum- 

 stances attending the transport and accumulation of vegetable 

 debris, supplies the solution of a problem akin to that of the 

 fly in amber and the manner in which it came there. 



