640 PEAT. 



nature of the country and the form of the ground 

 which it occupies. These deposits have often 

 the form of basin-like cavities, from circum- 

 stances that will be immediately apparent. Their 

 thickness is exceedingly variable, and has been 

 known to reach to fifty feet and upwards. 



In some instances, the formation of peat in 

 particular places has ceased ; in others, it is still 

 in progress, being maintained by the continuance 

 of those actions from which all the deposits of 

 this nature have originated. This is the suc- 

 cessive growth and decay of vegetable substances 

 of various kinds. It is not possible to enter on 

 this part of the subject here ; but it is necessary 

 to enumerate the different circumstances under 

 which this substance is formed, as it tends to 

 illustrate the different varieties which it presents. 



It is found on declivities which are easily 

 drained ; generally in very thin beds, and of a 

 loose texture, forming the mountain peat, or 

 heath soil, of agriculturists. On the margins of 

 lakes, it occurs in a solid form ; tending, by its 

 annual increase, ultimately to obliterate their 

 cavities, and thus to produce many of those ex- 



