PRESENT CHANGES IN THE EARTH. 



Fig. 43. 



bergs are sometimes very extensive. A French expe- 

 dition measured several which were a mile in breadth, 

 and one which was 13 miles long and 100 feet high. 

 Icebergs appear often in great numbers. Scoresby 

 counted 500 of them starting from the frozen regions at 

 one time for the south. Dr. Kane saw 280 in Baffin's 

 Bay at one time. Like glaciers, icebergs are more or 

 less loaded with fragments of rock, great and small, and 

 this load is dropped in the sea as the iceberg melts. It 

 is supposed that the Banks of Newfoundland were in 

 great part made by deposition from icebergs, and the 

 accumulation is constantly going on. These bergs not 

 only drop material, but they grind much of it up into 

 sand, and even mud, by dragging, as they often do, on 

 the floor of the sea. Sometimes they are stranded, and 

 then, moved by the waves, they roll back and forth, stir- 

 ring up the muddy bottom, and crushing any fragment 



