496 



[Ch. XLIV. 



animal 



ENCLOSING 01' FOSSILS IN PEAT, 



* 



Growth of peaty and preservation of vegetable ar, 

 remains therein. — The generation of peat, when 

 pletely under water, is confined to moist situations, where 

 the temperature is low. It may consist of any of the nu- 

 merous plants which are capable of growing in such stations ; 



com 



moss 



marshes 



this plant having the property of throwing up new shoots in 

 its upper part, while its lower extremities are decaying,^ 



may 



in peat ; and their organisation is often so entire that there 



discriminatin 



Analysis of 



— In general, says Sir H. Davy, one 



from 



esiduum consi 

 e substratum 



of earths usually of the same kind as the 

 clay, marl, gravel, or rock, on which they are found, together 

 with oxide of iron. ^ The peat of the chalk counties of 

 England,' observes the same writer, ^ contains much gypsum: 

 but I have found very little in any specimens from Ireland 

 or Scotland, and in general these peats contain very little 

 saline matter.' f From the researches of Dr. MacCuUoch, it 

 appears that peat is intermediate between simple vegetable 



matter and lignite. J 



Peat ahundant in cold and humid climates. — Peat is some- 

 times formed on a declivity in mountainous regions, where 

 there is much moisture ; but in such situations it rarely, if 

 ever, exceeds four feet in thickness. In bogs, and in low 

 grou.nds into which alluvial peat is drifted, it is found forty 

 feet thick, and upwards ; but in such cases it generally owes 

 one half of its volume to the water which it contains. It 

 has seldom, if ever, been discovered within the tropics ; and 

 it rarely occurs in the valleys, even in the south of Prance 

 and Spain. It abounds more and more, in proportion as we 

 advance farther from the equator, and becomes not only 

 more frequent but more inflammable in northern latitudes. § 



* For a catalogue of plants which 

 form peat, see Kev. Dr. Hennie's Essays 

 on Peat, p. 171; and Dr. MacCuUoch's 

 Western Isles, vol. i. p. 129. 



t Irish Bog Eeports, p. 209. 



+ 



+ 



System of Geology, vol. ii. p. 353 

 Eev. Dr. Kennie on Peat, p. 260. 



■■■ t 



4 



• I 



1. 



^ 



