The Development of Vegetation in the English Lakes. 263 



screes or rough pasture, the flatter hill tops are usually moorland. Only 

 alluvia and the gentler soil-covered slopes can be cultivated, and hence the 

 above ratio, though rough, is a fairly accurate expression of the character of 

 the drainage system. From the figures given, it will be seen that the lake 

 drainage systems fall into two classes, characterised by low and high propor- 

 tions of cultivable land respectively. 



Table I. — Effects of Erosion. 





Percentage of 



Lake shore to 



Eelative 



Lake. 



drainage system 



30 feet depth. 



transparency 





cultivable. 



Per cent, rocky. 



of lake -water. 





5-2 



73 



m. 



9 





5-4 



66 



8-3 





6-0 



50 



8-0 





8-0 



47 



8 



Hawes Water 



7-7 



25 



5-8 





10-0 



33 



5-5 





29 -4 



29 



2-2 





21 -8 



27 



5-4 





29 -4 



28 



5-5 





16 -6 



28 



5-4 





45 '4 



12 



3 1 



The second column in this Table shows the approximate proportion of the 

 shore-line of each lake, which is rocky. From the soundings along the shores 

 the average depth to which stones or rock extend has been determined, the 

 deeper part of the shores being silted and soft. Taking 30 feet (9"2 m.) as 

 a maximum, the percentage of the shore-line which is rocky can thus be 

 obtained very approximately for each lake. 



As the soundings on which these are based were made chiefly in bays, the 

 figures given are possibly too small. They are, however, truly comparable. 

 AYhile the small size of Esthwaite may be the cause of the silted nature of 

 its shores, as compared with Coniston, Windermere, and Ullswater, it cannot 

 be assumed that the high degree of silting in the latter lakes is due to the 

 slight effects of wave action, for Derwentwater, both smaller and with more 

 irregular shores, has more rocky shore-lines. Similarly, Wastwater, in which 

 the degree of wave action is almost the same as in Windermere, has shores 

 which are much less silted. By comparison with the first column in the 

 Table it will be seen that the rocky lakes (Wastwater to Crummock) lie 

 among steep slopes and uncultivated land, the silted lakes (Derwentwater to 

 Esthwaite) lie among the gentler soil-covered slopes. It seems a fair assump- 

 tion, then, that the character of the shore-line, whether silted or rocky, 

 depends largely upon the character of the surrounding country ; but it should 



