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Ch. XLVL] 



IN SUBAQUEOUS DEPOSITS. 



53 



O 



parts are lapidified, wliile the more durable do not waste 

 away till afterwards, when the supply has failed, and so never 

 become petrified. The converse of these circumstances gives 

 rise to exactly opposite results. 



Professor Goppert, of Breslau, has instituted a series of 

 curious experiments, in which he has succeeded in producing 

 some very remarkable imitations of fossil petrifactions. He 

 placed recent ferns between soft layers of clay, dried these in 

 the shade, and then slowly and gradually heated them, till 

 the clay was red-hot. The result was the production of so 

 perfect a counterpart of fossil plants as might have deceived 

 an experienced geologist. According to the different degrees 

 of heat applied, the plants were obtained in a brown or per- 

 fectly carbonised condition ; and sometimes, but more rarely, 

 they were in a black shining state, adhering closely to the 

 layer of clay. If the red heat was sustained until all the 

 organic matter was burnt up, only an impression of the plant 



remained. 



The same chemist steeped plants in a moderately strong 

 solution of sulphate of iron, and left them immersed in it for 

 several days, until they were thoroughly soaked in the liquid. 

 They were then dried, and kept heated until they would no 

 longer shrink in volume, and until every trace of organic 



matter 



them 



oxide formed by this process had taken the form of the plants. 

 A variety of other experiments were made by steeping animal 

 anri vpcypfahlp snbstannf^s in siliceous. calc^Creous, and metallic 



miner 



time 



than had been previously supposed."^ 



/ 



— I have observed the elytra and other 



parts of beetles in a band of fissile clay, separating two beds 

 of recent shell-marl, in the Loch of Kinnordy in Forfarshire. 

 Amongst these, Mr. Curtis recognised Elator Uneatus and 

 Atopa cervina^ species still living in Scotland. These, as well 



accomnanied them 



to terrestrial, not aquatic, species, and must have been 



^- Goppert, PoggendorfTs Aiinalen part iv., Leipsic, 1836. See also Lyell's 

 der Phjsik und Chemie, vol. xxxviii. Manual of GreoL, p. 49. 



