Vol. 62.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 



CXX1 



' hang ' are drained by streams which have nearly or quite 

 established their base-levels ; although, when these streams run at 

 the bottom of narrow gorges, the effect is one of a hanging valley. 

 Others, again, are due to glacial diversion ; but these are on a 

 . small scale. 



A point which may sometimes be important in diminishing the 

 erosive power of the stream of a hanging valley may be noticed. 

 When the grades of the tributaries are adjusted to the main stream, 

 the plane of saturation in the main stream and its tributaries may 

 coincide with the surface of the ground. When a main stream has 

 deepened its valley, causing its tributaries to hang, the plane of 

 saturation of the latter may be lowered, on account of springs 

 breaking out on the side of the main valley below the tributaries, 

 thus diminishing the volume of the latter. 



Before leaving this part of the subject I may say a few words 

 regarding the sizes of some of the principal hanging valleys of the 

 district, and the heights at which they ' mouth,' for I believe that 

 many are unaware of the importance of some of these valleys. 



Fig. 10. — The hanging valley of Bleaberry Tarn. (Seep, cxocii.) 



Watershed 2385 



Mouths 1350 Buttermei 



33* 



Sourmilk 

 Gill 



[Heights are indicated in feet.] 



[Scales, horizontal and vertical : 3 inches = 1 mile.] 



The largest is Measand Beck near Hawes water, which has a total 

 length of about 3 miles. Along a portion of this distance its valley - 

 noor is nearly flat, forming Fordingdale Bottom. Seathwaite-Tarn 

 valley above the Duddon we have already noticed, as being 2 miles 

 in length measured along a straight line. Church Beck, on the 

 other side of the Coniston Fells, has a course of nearly 2 miles 

 above the point where it mouths, and Sty-Head Beck occupies 

 1J miles from Sty-Head Pass to its ' mouth.' Several others are of 

 about this size. 



vol. lxii. i 



