VII] MOORLAND ASSOCIATIONS 189 



way back have their banks (see figure 29) fringed with sloping 

 banks of bare peat. In times of drought, the bed of these streams 

 contains very little water which may temporarily disappear ; but 

 after heavy rain-storms, the stream is a rapid torrent of brown, 

 peaty water. Every storm results in quantities of peat being 

 carried away, in the stream winning its way further back into the 

 peat, and in the channels becoming wider and deeper. Numerous 

 tributary streams also are formed in course of time; and 

 eventually the network of peaty channels at the head coalesces 

 with a similar system belonging to the stream which flows 

 down the opposite hill-side. The peat-moor which formerly 

 was the gathering ground of both rivers, is thus divided up 

 into detached masses of peat, locally known as " peat-hags " 

 (figure 31) ; and the final disappearance of even these is merely 

 a matter of time. 



It is obvious that this process results in a drying up of the 

 peat of the original cotton-grass moor ; and it is most interesting 

 to trace a series of degradation changes of the now decaying 

 peat moor. The first change of importance of the vegetation 

 appears to be the dying out of the more hydrophilous species, 

 such as Eriophorum vaginatum and E. angustifolium, and the 

 increase, on the summits of the peaty "islands" or "peat-hags," 

 of plants, such as Vaccinium Myrtillus and Empetrum nigrum, 

 which can tolerate the new and drier soil conditions. 



The composition of the upper layers of the peat of these 

 retrogressive moors has, during the course of the present in- 

 vestigation, been carefully examined; and it has been found 

 that the peat consists in its upper layers almost wholly of the 

 remains of Eriophorum. The succession therefore of cotton- 

 grass moor to the series of retrogressive moors here being 

 described, is established beyond doubt. 



THE PEAK OF DERBYSHIRE 



. As the Peak of Derbyshire is covered by retrogressive 

 moorland, a short description of this the most important 

 topographical feature of the district will not be out of place 

 at this juncture (cf. figure 32). 



The Peak is a plateau of Kinderscout sandstone varying in 

 height from about 1750 feet (533 m.) at its eastern extremity 



