Yol. 50.] ME. CHAS. DAVISON ON SNOWDRIFT DEPOSITS. 479 



they cut away earth and sand in minute particles from the wind- 

 ward side of any hill or rising ground in their course. 1 



Transported of the Dust. — In whichever way the dust is derived, 

 it will be driven with or after the snow and deposited in the same 

 places, either mixed with or covering the drifts. That it should 

 ever be noticed in the act of drifting with the snow is improbable, 

 considering its extreme fineness. Nares records, however, " a 

 blinding snowdrift mixed with sand and small pebbles which were 

 carried by the fury of the storm." Snow and sand are sometimes 

 driven in the faces of travellers as they walk, so that they can 

 scarcely keep their eyes open. During his journey along the Lower 

 Aniuj River, in North Siberia, von Matuischkin made a similar 

 observation. "The death-like stillness which prevailed," he says, 

 was " suddenly broken by violent gusts of wind, howling and 

 sweeping through the ravines, and whirling up high columns of 

 snow and sand." 2 



Long after all the snow has been blown away from exposed places 

 dust may continue to be conveyed by the wind to the surface of 

 snowdrifts. " In consequence of the bareness of the land from 

 snow," Nares remarks on Sept. 19th, 1875, " the dust has been carried 

 off by the wind, and has discoloured all the floebergs. This evidently 

 accounts for the dust sediment left at the bottom of the water pools 

 on the surface of the floes, and for that frozen deeply into the ice " 

 (vol. i. p. 149). Nor are dust-storms unknown in Arctic regions, one 

 that occurred on July 9th, 18S2, 3 being recorded by Greely. It is 

 evident that some of the dust transported in this way may 

 ultimately form a part of deposits from snowdrift. 



3. Hardening of Snowdrifts. 



So long as the snow remains loose and powdery on the surface, 

 snow-banks accumulated on open ground are continually shifting 

 like sand-dunes, and drifts in many places are liable to removal 

 with a change of wind. 4 Under these conditions, deposits from 

 snowdrift would not have a much greater prospect of preservation 

 than any ordinary, unprotected, seolian formation, unless they occur 

 in very sheltered valleys and ravines. Generally, however, the 

 snow, by superficial melting and re-freezing, is soon encrusted with 

 a layer of ice, or it is closely packed by the action of the wind. The 

 dust is thus imprisoned in the hardened snow, and the deposit from it 

 tends to become a permanent addition to the products of former 

 years. 



Snow hardened by the Action of the Sun. — Long before the tempe- 

 rature of the air reaches the freezing-point, the sun has sufficient 



1 De Long, vol. i. pp. 299-367, vol. ii. p. 517 ; Greely, vol. i. pp. 211, 224 ; 

 Have?, p. 285; M'Clintock, pp. 210-11 ; ' Nature,' vol. xxxiii. (Jan. 14th, 1886) 

 pp. 244-45; Nordenskiold, vol. ii. p. 103; Payer, vol. i. p. 254, vol. ii. pp. 11, 

 52-53, 114 ; Wrangell, pp. 102-3, 104. 



2 Koldewey, p. 422 ; Markhain, p. 154 ; Nares, vol. i. p. 142 ; Wrangell, 

 p. 194. 



3 Greely, vol. i. p. 410. 4 Nares, vol. i. pp. 273-74. 



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