644 THE FRESH-WATER LOCHS OF SCOTLAND 
applies. The remainder is a narrow valley, 5 k miles long, directed 
approximately north-east and south-west, called Lake Wairaumoana, 
which is connected to Lake Waikaremoana by a passage half a mile 
in width, known as the Straits of Manaia. The area of Lake 
Waikaremoana is about 15 square miles, and of Lake Wairaumoana 
about 6 square miles. The greatest depth recorded in the whole lake 
is one of 846 feet in Lake Waikaremoana, and occurs within a depres- 
sion having an area of 1*3 square miles exceeding 800 feet in depth. 
The deepest sounding taken in Lake Wairaumoana is 375 feet. The 
mean depth of Lake Waikaremoana is 397 feet, or 47 per cent, 
of the maximum depth ; the mean depth of Lake Wairaumoana is 
175 feet, or 49 per cent. Lucas considers these lakes a system of 
radiating valleys, having the deepest part at the point where all 
the valleys meet. 
Lake Wakatipu is drained by the Kawarau River, a tributary of 
the Clutha River, in South Island, and lies at a height of 1016 feet 
above sea-level, extending from lat. 44° 50' to 45° 20' S., and from 
long. 168° 20' to 168° 43' E. The two ends of the lake trend in a 
direction almost north and south, but the middle part runs nearly 
east and west. The length is 49 miles, the greatest breadth about 
3 miles, and the area exceeds 112 square miles. The maximum depth 
obtained by Lucas was 1242 feet ; the volume of water is 15 cubic 
miles, and the mean depth 707 feet. The lake appears to be a 
mountain valley filled with water. 
The Clutha River takes its rise in the two lakes Wanaka (area 
75 square miles) and Hawea (area 48 square miles), in which maxi- 
mum depths of 1085 and 1285 feet respectively have been reported. 
Lake Manapouri, 597 feet above the sea, extends from 
lat. 45° 27' to 45° 35' S., and from long. 167° 28' to 167° 40' E. It 
is very complicated in outline, and covers an area of about 56 square 
miles. The greatest depth, 1458 feet, occurred within a large depres- 
sion about 2^ square miles in area, which exceeds 1400 feet in depth, 
the mean depth being 328 feet. The surface of the water lies at 
approximately 597 feet above sea-level. The lake receives from the 
north the surplus waters of Lake Te Anau (36 miles in length and 
1 to 6 miles in breath), and drains south by the Waiau into the 
South Pacific Ocean. 
CRATER LAKES 
Crater lakes would appear to constitute a class by themselves, 
since they are not directly connected with river drainage, and are to a 
very small extent influenced by climatic oscillations. They occupv 
the hollows in the summits of the cones of dormant volcanoes, and the 
