PEAT. 337 



under an alluvial soil. Such peat was that of the ori- 

 ginal marsh, or Jake, in such a place ; while the allu- 

 via which buried it have, in souie cases, prevented its 

 renewal, by producing a non-vegetating soil, or one 

 which has been brought into pasturage or cultivation; 

 as, in others, successive marshes and productions of 

 peat may have followed successive deposits of alluvia. 

 And if alternating beds of marl or shells indicate a 

 former lake more especially, pointing out not less its 

 antient extent, so do such beds, when of marine ori- 

 gin, prove those changes in the mutual boundary of 

 the sea and land to which I have just alluded. 



Mountain peat occurs wherever the drainage is 

 rapid and perfect, and is therefore most common in 

 mountainous countries, though not thus limited. It 

 is generally incompact, varying in thickness from a 

 few inches to a foot or two, and rarely much more. 

 In an agricultural view, it is often very important, 

 from its great extent, and the facility with which it is 

 brought into cultivation, especially when lying on dry 

 moorlands ; though it is generally a worthless fuel, 

 from its incornpactness, except under the destructive 

 practice of paring, as turf. 



The variety of extent and situation occupied by 

 Marsh peat is very great, since it constitutes large 

 plains and the smallest mountain bogs, and occurs also 

 on the margins of lakes and sestuaries ; being, in the 

 latter cases, often united to lake and to maritime peat, 

 by transition, inasmuch as the shoaling of each first 

 produces a marsh. Hence considerable variations, 

 and also much additional confusion of character, from 

 the variety of the surface at different stages of its pro- 

 gress ; whence its transitions are from the most com- 

 pact peat of lakes to the most lax of mountain decli- 

 vities, as the drainage has differed at different places 



VOL. n. z 



