BRITISH MOSSES. 59 



cases a time when this process is arrested ; the artificial 

 drainage of the soil, or the physical position of the area, 

 prevents the re-formation of a morass, and the Sphagnum 

 dies away. So in many parts, if not universally, in 

 Sedgmoor, in Somerset, it is almost impossible to gather 

 a bit of Sphagnum, and the peat is well known to the turf 

 diggers not to be reproduced. Here the regulated drainage 

 of the level maintains the surface in the condition of 

 meadows or agricultural land. But in many cases, 

 especially on mountain sides or tops, when the Sphagnum 

 has died, and the peat undergone its last change into black 

 earth, a process of decay sets in under the influence of air 

 and water. The water lies in holes or " hags," or flows in 

 sluggish streams, wearing away the dead peat ; and the 

 surface of the soil is broken and uneven, small patches of 

 green surface with a rough growth of sedge or grass being 

 surrounded by wider spaces of black earth. Such is, or 

 was some years ago, the condition of the peat on the top 

 of Kinder Scout in Derbyshire ; on the parts of Dartmoor 

 around Cranmere Pool ; and such also it is described to be 

 on many of the Lowland hills of Scotland. 



Sedgmoor. In some cases the Peat Mosses have been 

 originally arms of the sea, and the peat has only grown 

 after the exclusion of the salt water. Such appears to be 

 the history of Sedgmoor, the great plain of Central Somerset. 

 Northward it is bounded by the Mendips ; eastward lies 

 Glastonbury with its Tor or hill ; westward the Bristol 

 Channel, The plain is intersected by the low line of the 

 Pouldon Hills, once a long level-backed island or pro- 

 montory in the estuary and afterwards in the morass ; and 



