DR. W. FLiaiTT, GREENLAND METEORITES. 463 



distributed in not inconsiderable quantity on sliore-iee, as well on 

 ice thirty miles from the coast and at a height of 700 metres 

 above the sea. The dust of both localities has probably a common 

 origin. 



The cryoconite is chiefly met with in the holes of the ice, form- 

 ing a layer of grey powder at the bottom of the water filling the 

 holes. Considerable quantities of this substance are often carried 

 down by the streams which traverse the glacier in all directions. 

 The ice-hills which feed these streams lie towards the east, on a 

 slowly rising undulating plateau, on the surface of which not the 

 slightest trace of stone or larger rock -masses was observed. The 

 actual position of this material, to which Nordenskjold has given 

 the name of cryoconite ^Kpvoq ice, and Koviq dust), in open hollows 

 on the surface of the glacier, precluded the possibility of its hav- 

 ing been derived from the ground beneath. 



The grey powder contained a not inconsiderable amount of or- 

 ganic matter, which, even at the low temperature of the ice, under- 

 goes putrefactive decomposition. A quantity, amounting to from 

 two to three cubic metres, which was lying in the dried-up bed of 

 a glacier-stream, emitted a very offensive odour, bearing some 

 resemblance to that of butyric acid. 



When examined with the microscope, the chief constituent of 

 this powder appears to consist of colourless, crystalline, angular, 

 transparent grains, among which are a few yellow and less trans- 

 l^arent. Some had distict cleavage-surfaces, and were possibly a 

 felspar ; other crystal fragments, having a green colour, were 

 probably augite ; while other black, opaque particles could be re- 

 moved with a magnet. These foreign constitutents, however, 

 are present in so small a quantity that, if all the white grains con- 

 sist of one and the same mineral, it may be regarded as homo- 

 geneous. The specific gravity of this mineral is 2-63 ; the hard- 

 ness apparently inconsiderable, and the form probably monoclinic. 

 It resists the action of acids ; by long digestion with sulphuric 

 acid 7 • 73 per cent., with hydrochloric acid 16 '46 per cent, were 

 dissolved. Lime-carbonate was not present. According to 

 Lindstrom's analysis, it consists of- 



Silicic acid - 



Phosphoric acid 



Alumina 



Iron oxide - 



Iron protoxide 



Manganese protoxide 



Lime 



Magnesia 



This composition corresponds with the formula : 



2R0, SiOa + AlgOg, SSiOg + HgO. 

 The origin of this cryoconite is highly enigmatical. That it is 

 not a product of the weathering of the gneiss of the coast is shown 



* This passed off when the mineral was heated to temperatures ranging 

 from 100° to a red heat. 



62-65 



Potash 



2-02 



0-11 



Soda 



4-01 



14-93 



Chlorine 



0-06 



0-74 



Water (hygroscopic) 



0-34 



4-64 



Organic matter and 





0-07 



combined water* - 



2-86 



5-09 

 3-00 









100-12 



