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Art. XLVr. — On the Occurrence of Native Mercury near Pakaraka, Bay of 

 Islands. By Captain F. W. Hutton, F.G.S. 



(With Illustration.) 

 {Read before the Auchlancl Institute, October 10, 1870.] 

 A FEW miles south-east of the Omapere Lake, near the Bay of Islands, lies a 

 group of hot and cold springs, of great interest on account both of the peculiar 

 mineral character exhibited by them, and the deposits of mercury and cinnabar 

 that some of them form. 



As long ago as 1866, it was known that mercury had been found at these 

 springs, but, as only very small quantities had been obtained from one spot 

 alone, it was the general opinion that some person had broken a thermometer 

 when taking the temperature of the water. Having, however, been informed 

 that small grains of cinnabar had also been found in the sand, I was induced, 

 in June, 1869, to make a visit to the place. This visit, owing to circum- 

 stances over which I had no control, was unfortunately a very hurried one, 

 and limited to a few hours only, but, thanks to the guidance of my friend, 

 Mr. Henry Ireland, of Waimate, it was very successful, for not only did we 

 find mercury in the sand in the place already alluded to, but also in two other 

 localities, in veins in the rock, accompanied by cinnabar and sulphur. 



The series of springs which I have to describe are, I believe, the most 

 important in the district, although many others exist. They commence with 

 a group of large cold springs (a), situated in a crateriform hollow in low 

 undulating fern-covered hills composed of brown, soft, ai-gillaceous, thin-bedd.d 

 sandstone, with occasional beds of lignite. These rocks are probably not of an 

 older date than Upper Miocene, and may be even of Pliocene age. After 

 leaving this hollow the stream flows through a narrow gorge, about a quarter 

 of a mile in length, which opens out into another small hollow, in which, 

 among others, some warm springs are found (b and c), containing mercury 

 and sulphur. 



The stream then flows through another gorge, and again emerges into a 

 level irregularly-shaped hollow, of much larger dimensions than either of the 

 others, in which numerous springs, both hot and cold, are situated. On leaving 

 this hollow the stream flows through a narrow passage, and empties itself into 

 a small lake. 



The water of this stream both smells and tastes strongly of sulphuretted 

 hydrogen, and is decidedly acid. Most of the springs are cold, some are tepid, 

 and a few, situated in the centre of the last and largest hollow (e and f), are 

 hot, but the temperature of the hottest of them is probably not much more 

 than 120°F. In one of these hot springs (e), deposits of alum and sulphur are 

 found • many of them show traces of sulphur, and almost all have deposited 

 silica, although not in large quantities. 



