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higli and abrupt towards the south, where they ascend to an altitude of aboiit 

 120 feet, rising gently on the northern side, and forming a shingle plain, with 

 a great deal of swampy ground, cut through by numerous smaller rivulets and 

 creeks. 



The whole plains are surrounded by ranges 4000 to 6000 feet high, con- 

 sisting of younger palaeozoic or older mesozoic rocks, which, in many localities, 

 are cut through by diorites, amygdaloids, and other trappean rocks. 



About three miles in a north-east direction from the beginning of the 

 Waiau-ua Gorge, and about 200 yards from the foot of the northern ranges, 

 the thermal springs are situated. They occur over an ai-ea of about 2000 

 square yards, in a perfectly dry position, at an altitude of 1162 feet above the 

 level of the sea, as calculated from a single bax'ometrical observation. They 

 are situated about five feet below the surface of the plains, and on a line 

 running north-east to the south-west. There are four principal basins, having four 

 smaller ones close to them, the outlets of which join together and form a 

 swampy creek lunning into the Percival, one of the tributaries of the Hanmer. 



We may safely assume, from the geological features of the country in which 

 these springs take their rise, that they issue from a fault or fissure in the 

 older sedimentary beds which has been formed in connection with trappean 

 rocks, making their appearance at various intervals towards the close of the 

 mesozoic period. 



I have been informed that some other springs of similar nature occur on 

 the northern side of the Percival Range, as well as on the southern banks of 

 the Hurunui, above Lake Sumner, and these probably owe their origin to the 

 same agencies. 



Whatever their oi'igin may be, these spiings are very difierent from those 

 of the lake regions in the North Island, which stand in close connection to the 

 volcanic action still going on in that part of New Zealand. 



The principal spring of the Hanmer Plains is Ksituated in the north-eastern 

 corner of the area. This basin has an average breadth of twelve yards. The 

 water which it contains is perfectly colourless at the shallow sides, whilst 

 towards the centre, which is much deeper, it has a beautiful greenish Vjlue tint. 

 It has a well-defined taste and smell of sulphuretted hydrogen. In the centre, 

 at several spots, the water rises, continually throwing up large bubbles. 

 Temperature on the sides, 97° 2' ; in the centre, amongst the bubbles, on 

 bottom, 104° 1'. Depth about eight feet. Temperatui-e of air, 70° S' ; sky 

 overcast.* 



This largest basin, No. 1, is the one which has principally been used for 



* I may here observe that I made the observations in the centre of the basins Avith a 

 good self-registering thermometer of Negretti and Yambra, which we let down (Mr. 

 Hugh M'llraith, who was my companion that day, kindly assisting me) by a flax rope 

 drawn across the basin, and to which I had tied the instrument. 



