GEOLOGICAL OBSERVATIONS 



A description of the craters of Erebus has already- 

 been given in the narrative of this work, and the fact is 

 emphasized that the interior of the old crater is largely 

 filled with layers of large felspar crystals and pumice, 

 alternating with beds of snow. Five of these felspar 

 crystals are figured on the accompanying plate. 



ADDITIONAL NOTES ON ERUPTIONS 



By JAMES MURRAY 



We were not so fortunate as to witness an eruption 

 of any great moment. The activity of Mount Erebus 

 showed in the form of increased volume of the steam- 

 cloud or " smoke-cloud " ejected from the crater, and in 

 a red glow or flare at the crater, often visible at night. 

 There were also steam eruptions from fumaroles more or 

 less distant, sometimes many miles distant from the active 

 crater. 



The Smoke- Cloud. — We referred to the cloud of 

 steam which issued from the crater as the " smoke-cloud," 

 to leave no chance of confounding it with the great 

 laminated cloud which commonlj^ hung over the mountain. 

 The variations in the volume of the smoke-cloud were 

 associated with high and low barometer. Occasionally, 

 for a few days, no smoke was visible, and this was 

 usually at times of high pressure. Even then we could 

 not be sure that there was no smoke issuing, as there is a 

 gap in the crater not visible from our camp. Great 

 activity in the ejection of steam occurred with the glass 

 as high as 29.5 (very high for this region) , and as low as 

 28.3 (pretty nearly our minimum). 



A large volume of cloud was often thrown up with 

 great force, to a height of several thousand feet, some- 

 times as much as 5000 or 6000 ft., where it spread out 



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