230 Geological Society. 



In conclusion, the Author states his indebtedness to Prof. T. Rupert 

 Jones, F.R.S., and Prof. J. W. Judd, F.R.S. ; to Dr. W. P. Hume, 

 F.G.S., Dr. G. J. Hinde, V.P.G.S., Dr. J. W. Gregory, F.G.S., and 

 Graf Solms-Laubach ; and to George Murray, Esq., F.L.S., — for 

 valuable aid during the preparation of the present work. 



2. ' On Deposits from Snowdrifts, with Special Reference to the 

 Origin of the Loess and the Preservation of Mammoth-remains.' 

 By Charles Davison, Esq., M.A., E.G.S. 



When the temperature is several degrees below freezing-point, 

 snow recently fallen is fine and powdery, and is easily drifted by 

 the wind. If a fall of snow has been preceded by dry frosty 

 weather, the interstitial ice in the frozen ground is evaporated, and 

 the dust so formed may be drifted with the snow and deposited in 

 the same places. The snowdrifts as a rule are soon hardened by 

 the action of the sun or wind, and the dust is thus imprisoned in 

 the snow. As the snow decays, by melting and evaporation, a 

 coating of dust is extruded on the surface of the drifts, and, in- 

 creasing continually in thickness as the snow wastes away, is finally 

 left upon the ground as a layer of mud, which coalesces with that 

 of previous years. The deposit so formed is fine in texture, 

 unstratified, and, as experiments show, mica-flakes included in it are 

 inclined at all angles to the horizon. 



The Author describes several such deposits both in this country 

 and in the Arctic regions ; and suggests (1) that the loess is such a 

 deposit from snowdrifts, chiefly formed when the climate was much 

 colder, but still very slowly growing ; (2) that mammoths suffocated 

 in snowdrifts are subsequently embedded, and their remains pre- 

 served, in the deposits from them ; and (3) that the ground-ice 

 formation of Alaska, etc., is the remains of heavy snowdrifts when 

 the coating of earth attained a thickness greater than that which 

 the summer heat can effectually penetrate. 



3. ' Additions to the Fauna of the Olenellus-zone of the North- 

 west Highlands.' By B. N. Peach, Esq., E.R.S., F.G.S. (Com- 

 municated by permission of the Director-General of the Geological 

 Survey.) 



New material obtained by the Officers of the Geological Survey 

 has been placed in the Author's hands, and as a result he is enabled 

 to add information concerning the species of Olenellus previously 

 described by him (0. Lapworthi); he also describes a new variety 

 of this species, three new species of the genus, a new subgenus of 

 Olenellus, and a form provisionally referred to Bathynotus. 



He discusses certain theoretical points based upon the study of 

 the remains described in the paper, and states that these make it 

 probable that the dispersal of the Olenellids was from the Old World 

 towards the New. 



