I'HVSICAL AND CLIMATAL CONDITIONS. 101 



question l»y asL'ertiiiiiiii<,' tlio deiiositioii of iiiiuinu lioiilder- 

 C'lav, or at- leiisl of a (It'j)osiL <»t' sund and clav, with 

 fnitfnicnls of various rocks over areas i)erliaps as <freat as 

 those HOW covered with similar (U'posits in tlie northern 

 lieniisjihere. It is most instructive to find that a bed of 

 this stony mud is in ])rocess of deposition from ihjatiiiij 

 ice in Jie soutiiern ocean, and tiiis with such rapidity, 

 that tlie foraniinifera ami other or^'anisms elsewhere 

 forming; the dee[>-sea ooze are (juite maskeil by it, while 

 it is also ])()ssil)le that in some places all traces of these 

 may be dissolved out by carl)onic acid. It is further 

 interestiuff to find such deposition taking place so exten- 

 sively under conditi<jns proljably much less favourable 

 t^vin those which prevailed in Kurope and America 

 during the great Tleistocene subsidence. 



These facts fully confirm the conclusions stated above 

 with reference to the Itoulder-clay or till of North 

 America, and which 1 have endeavoured to establish by 

 the nature of the deposits now forming in the areas of 

 ice-drift of the American coast, by the distribution and 

 chemical contlition of the boulder-clay itself, and by the 

 occurrence of marine organisms in it. It is to l)e hoped 

 that in future we shall not have so confident assertion 

 that these remarkable clays are due to the direct action 

 of land ice on the surface of our continents. 



If the bottom of the South Pacific and Antarctic 

 oceans could be elevated into land, we should see the 

 evidence of glacier action on the hills representing the 

 islands now out of water and extending from these a vast 

 area of boulder-clay reaching as far north as our similar 

 records of the Pleistocene submergence spread to the 

 south, and probably holding in many places marine 

 organic remains, though there might be expected to be 



