THE LAKES OF SNOWDONIA AND EASTERN CARNARVONSHIRE. 433 



The lake is 3530 yards long, and has a maximum breadth of 595 yards. Its waters 

 cover an area of 1,340,800 square yards. The mean breadth is 380 yards, and this is 

 11 per cent, of its length. During the survey nineteen sections were taken, the total 

 number of soundings amounting to 286. The deepest sounding obtained was 94 feet, 

 just opposite the town of Llanberis. So Padarn is nowhere as deep as Peris. The 

 mean depth is 52*4 feet, and this is 56 per cent, of the maximum depth. The total 

 bulk of water contained in the lake is approximately 632 million cubic feet. The 

 upper half of the lake is deeper than the lower half. The contour-lines for the most 

 part follow the inflexions of its coast lines, broadening out at head of the lake, and 

 narrowing where the lake narrows. The 80 feet contour-line encloses 13*5 per cent, 

 of the total superficial area, It has a remarkable form — a broad swollen head tapering 

 to a narrow channel, which runs nearly half way down the length of the lake. This 

 channel bulges out a little about its middle. Nearly 50 per cent, of the total super- 

 ficial area of the lake is enclosed within the 60 feet contour-line, and as much as 70 

 per cent, lies within the 40 feet contour-line. Only 18 per cent, corresponds to depths 

 below 20 feet. 



A longitudinal section of the lake is shown along the line A-B ; and in addition 

 three cross-sections are given — G-H near the head and across the deepest part, E-F 

 about the middle, and O-D from a point just above the upper end of the railway 

 tunnel at a point a little lower down on the opposite side (Plate VIII.). These with 

 the map (Plate IV.) show that the configuration of this lake-basin is again simple. The 

 same characteristic trough-shaped form is shown with steeply sloping sides and a more 

 or less flat bottom. As one would expect, the slope is steeper on the Dinorwic side, 

 corresponding to the steeper slope of the land on that side. The longitudinal section 

 shows the steepness of the slope at the upper end of the lake, and also proves that the 

 deep basin ends at a point opposite the lower end of the railway tunnel, beyond which 

 the lake is comparatively shallow. 



7. Llyn Gwynant. — This beautiful lake is less than a mile long, its total length 

 being 1540 yards. It has a maximum width of 515 yards. Its waters cover an area 

 of about 545,800 square yards, and from this its mean breadth has been calculated to 

 be 354 yards, which is 23 per cent, of the total length. The lake lies in the Vale of 

 Gwynant, at a distance of about three miles from the head, and its main axis follows 

 the trend of that valley, running from north-east to south-west. From its upper end 

 an alluvial flat stretches up towards the head of the valley as far as Gwastad Agnes. 

 This flat consists almost entirely of meadow-land, and along it winds the river Glaslyn, 

 which, however, keeps pretty close to the Snowdon side, and enters the lake at the 

 angle between its head and the right margin. Several other small streams join the 

 lake, the majority of which come down from the hills on the left or south-east side. 

 The right or north-west side of Gwynant is very uniform in outline, the margin of the 

 lake running in almost a straight line. The south-eastern or left side is more irregular, 

 the lake-margin sweeping round in a wide curve from the entrance of the river, so as to 



