NEW ZEALAND— SOUTH ISLAND. 427 



by the sedimentary matter washed down with the mountain torrents. Without 

 counting numerous sparkling ponds or tarns less than a square mile in extent, 

 South Island contains about sixty basins, some of which cover an area of over 40 

 square miles and fill cavities 300 feet and upwards deep. Nearly all these great 

 reservoirs are grouped in the southern part of the island and on the east slope of 

 the mountains. Rising abruptly above the western seaboard, the New Zealand Alps 

 have too precipitous a slope on this side to allow the ruiming waters to collect in 

 large basins. But the opposite declivity and the plains stretching thence to the 

 east coast present numerous depressions where the glaciers have been replaced by 

 lakes, most of which have been formed in the intermediate zone between the 

 uplands and the plains. A straight line drawn across the chief flooded basins 

 from north-east to south-west for a distance of about 200 miles would run parallel 

 to the main Alpine chain, and would represent the direction of the axis of the 

 southern island. 



The northern group of lakes east of the highest section of the Alps appears to 

 be merely the remains of a labyrinth of inland waters, which formerly occupied 

 the vast Mackenzie Plains, and which are now disposed in countless secondary 

 cavities by moraines, heaps of erratic boulders, dams and sedimentary deposits. 

 These basins — Te Kapo, Pukaki, Ohau — were formerly much deeper, and are now 

 rapidly silting up, just as those farther north have already been filled in which 

 were at one time traversed by the river Waimakariri. The day may be predicted 

 when the glacial waters of the Waitaki, which now issue in a crystal stream from 

 the flooded depressions, will roll down in a turbid current to the plains. Although 

 its course scarcely exceeds 120 miles in length, the Waitaki is none the less a great 

 river, according to W. N. Blair five times more voluminous than the Thames, 

 although this writer gives no data in support of his statement.* 



Farther south the Clutha, which receives the overflow of the central group of 

 lakes, is a much larger watercourse, being compared by the same author with the 

 Nile. It is certainly the first river in New Zealand both for size and volume, its 

 catchment basin exceeding 8,000 square miles in extent. The Clutha has also 

 been more thoroughly explored than any other stream in South Island, thanks to 

 the rich gold-fields, which since the year 1862 have attracted thousands of miners 

 to the region about its headwaters. Wakatipu, one of the lakes belonging to this 

 system, is no less than 50 miles long, but only from 1 to 3 miles wide. It thus 

 presents the aspect of a winding river, without visible current, with a mean depth 

 of no less than 1,200 feet, and in its profoundest chasms sinking to 1,400 feet. On 

 both sides the encircling hills plunge abrupt!}^ into these abysmal waters. 



Te Anau, largest of all New Zealand lakes, lies beyond the Clutha basin at the 

 bead of the Waiau, a short stream flowing to the south coast. The lake fills a long 

 valley and several tributary branches for a space of 140 square miles, and in its 

 deepest part the sounding line has measured 940 feet. Te Anau is separated by a 

 narrow isthmus from Manapuri (Manipori), another lacustrine basin, which is also 

 said to be very deep, and which branches into numerous creeks and bays, winding 



* Scottish Geographical Magazine, November, 1887. 



