THE ACTIVE VOLCANOES OF NEW ZEALAND 



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alternating lava flows and fragmental deposits of the same material. 

 Ruapehu has not been in active eruption since early in the Recent 

 period, but Ngauruhoe and Tongariro continue to suffer regularly 

 weak outbursts. Evidence of this may be seen in Fig. 6. Accord- 

 ing to Marshall there has not been a flow of lava from a New 

 Zealand volcano in historic times, but Park and Speight believe that 

 in 1869 a lava flow escaped from the northwest side of Ngauruhoe 

 and that the fresh appearance of this lava attests its recent origin. 



Fig. 3. — Ruapehu (9,175 feet) from the Waiouru-Tokaanu road eight miles 

 distant. Looking across the Onetapu Desert covered with volcanic sand and cinders. 



Ruapehu. — This is an enormous mass of red to dark-gray lava 

 and scoriae rising from a plateau region. Its height has been 

 placed by various writers at 8,878 feet to 9,175 feet above sea-level, 

 and the latter may be considered as the more correct figure. It 

 has a large crater, approximately a mile in diameter, cut into on 

 the south-southeast side by a great ravine, so that the rim of the 

 crater consists of a series of prominent peaks. The crater is 

 occupied by a glacier which surrounds a small, hot lake said to be 

 about 600 feet in diameter. According to various reports, the 

 water sometimes boils, and apparently it is the sulphur water from 

 this lake which issues from the northeast side of the mountain. 



