206 Philip Lake — Bala Lake and River System. 



and on August 3, 1899, in a dry season, Mr. Hall and I found it to 

 be 15-3 feet below B.M. 543-7 (about a mile south-west of Llan- 

 gower), or 5284 feet above O.D. The level of the water, therefore, 

 seems to vary but little, and it may be taken as about 530 feet 

 above the sea. 



The depth of the lake is stated by Eamsay to be about 130 feet.' 

 On August 1, 1899, Mr. Hall, Mr. Scrivenor, and myself took 

 a series of soundings, and the greatest depth which we measured 

 was 126 feet. This was at a point a little distance north of the 

 Llangower peninsula. 



Our soundings were taken along the three lines shown upon 

 the map (Fig. 1). As they were made with * water-cord,' which 

 is liable to stretch, they are not exact, but (corrected by subsequent 

 experiment) they are probably not more than a few feet out in any 

 case. All the sections - (Fig. 2) showed that the sides of the lake 



Fig. 2. — Sections of Bala Lake along the lines A-B and E-F in Fig. 1. Scale 

 (horizontal and vertical), 3 inches = 1 mile. 



slope inwards at an angle, which, indeed, is not very steep ; but the 

 bottom of the slope is well defined, and the central portion of each 

 section is nearly flat. The maximum depth in the line A-B was 

 66 feet, in the line C-D 77 feet, and in the line E-F 126 feet. The 

 floor of the lake, therefore, appears to slope from north-east to 

 south-west, that is to say, in a direction opposite to the present 

 flow of the water. It would, however, require a moi'e extended 

 series of observations to prove that this slope is continuous. 



In the paper already mentioned,^ Ramsay assumes that there 

 never could have been any other outlet for the water of the lake 

 than the channel of the Dee ; and because the Dee flows over rock 

 in situ at a higher level than the bottom of the lake, he concludes 

 that the lake must lie in a rock basin. In the light of Mr. Marr's 

 recent researches on the tarns and lakes of Cumberland and 



1 Quart. Journ. Geol. Soc, vol. xxxii (1876), p. 219. 



2 Our positions were determined by compass bearings from the shore, and have no 

 pretensions to precise accuracy. The section A-B and the south-eastern half of the 

 section E-F are probably correct ; but in the north-western half of the section E-F 

 the angles of intersection were somewhat acute, and the positions of the soundings 

 are therefore not so accurately fixed. 



^ "On the Physical History of the Dee, Wales" : Quart. Journ. Geol. Soc, 

 vol. xxxii (1876), pp. 219-229. See also Mem. Geol. Surv., vol. iii (1881), 2nd ed., 

 pp. 314-323. 



