162 Association of American Geologists and Naturalists. 



material. It then is forced off by a strong off-shore wind, and after 

 drifting still farther north is stranded again, perhaps at a long distance 

 from its first anchorage. New overturns follow, fresh materials are 

 accumulated, but from waste, the whole mass becoming lighter, it is 

 once more floated off, and pursuing a somewhat devious course toward 

 the tropics, is gradually melted away. Could that part of the ocean's 

 bed over which such an iceberg has passed be laid bare for our inspec- 

 tion, what would be the appearances presented ? The early progress 

 of the mass would be marked by a deposition of large angular frag- 

 ments of polar rocks. Subsequent to the overturn there would be an 

 interval with few or no traces of its path, till the rocky portion of the 

 berg had resumed its original situation, when the deposition would be 

 continued, and these alternations would evidently correspond to the 

 number of overturns. The larger masses of rock would for the most 

 part be the first to drop out, and latterly the majority of matter might 

 consist of smaller and more rounded fragments, such as had been 

 worn by the grinding of the ice on the beach or bottom. Prior to the 

 last, or even the first stranding, all, or nearly all the rock and earth 

 originally contained in it might be deposited, when the latter portion of 

 its track would be marked by a comparatively scanty amount of ma- 

 terial from its more recent halting places, perhaps confusedly mixed, 

 and affording here and there some slight indications of the birth-place 

 of the berg, in the occasional presence of a fragment of the remote 

 Antarctic soil. 



Was there aught, ask^d Mr. C, in the evidences of ancient aqueo- 

 glacial action, analogous to such a mixed deposition, and irregular dis- 

 tribution of materials from widely separated localities, as would result 

 from the conjectural case here presented, or the actual one of the ice- 

 berg previously cited as fallen in with on the southern margin of the 

 Gulf Stream .? Did they explain any of the obstacles and apparent 

 anomalies presented by the aqueo-glacial theory of the drift formation ? 

 These were questions which he submitted for the decision of those 

 whose attention had been more specially directed to this subject. 



In reference to the advance and northern limits of icebergs from the 

 Antarctic in the eastern hemisphere, Mr. C. could state nothing from 

 his personal knowledge, farther than that they frequently occur at least 

 as low as the thirty-fifth parallel of latitude. During his residence in 

 New South Wales, in the summer and autumn of 1839-40, (Decem- 

 ber to March,) several ships arriving at Sydney from England, reported 

 having fallen in with large icebergs in the vicinity of the Cape of Good 

 Hope, at least 1800 miles from the nearest southern land ; along the 

 whole of which distance they possibly deposited material from their 

 polar starting point. 



