156 Association of American Geologists and Naturalists. 



latitude. He remembered however, having encountered in November, 

 1825, off the entrance to the Rio de la Plata, in latitude 35° south, longi- 

 tude 49° west, or thereabouts, a number of icebergs, some of which 

 were of large magnitude ; a reference to the chart would, he observed, 

 show to what a vast distance from their birth-place these floating masses 

 had been driven by wind and current. 



In the month of August, 1827, while crossing the Grand Banks, in 

 latitude 46° 30' north, longitude 48° west, Mr. C. passed within less 

 than a mile of a large berg which was stranded in between eighty and 

 ninety fathoms water. The wind was light, but a heavy swell was 

 running from the westward, and the huge pile could be distinctly seen 

 to rock and shake violently as it ground heavily down into its bed with 

 every surge. Owing to its longest diameter facing the swell, the mass 

 had an oscillatory or serai-rotary back and forward nnotion upon its ver- 

 tical axis, according as the sea broke upon one or the other extremity, 

 which it did with so much force at times as to turn the berg apparently 

 full half round ; in this situation it would remain till another heavy 

 surge striking the opposite end would force it back and round in the 

 other direction. The vessel was sufficiently near for Mr. C. to perceive 

 distinctly, large fragments of rock and quantities of earthy matter im- 

 bedded in the sides of the iceberg, and to see from the fore yard, that 

 the water for at least a quarter of a mile round it, was full of mud, stirred 

 up from the bottom by the violent rolling and crushing of the mass. 

 This movement was accompanied by a harsh grating noise, with occa- 

 sional cracking reports, resembling those produced by blasting rocks, 

 which might have been heard ten or twelve miles. The height of this 

 berg was estimated by Mr. C, at from fifty to seventy feet, and its length 

 at four hundred yards. While examining it through the glass, it was 

 observed to incline suddenly more than usual, and in the next moment, 

 with a crash and roar that were truly fearful, and amid a whirlwind of 

 spray and foam, the whole enormous pile rolled over on its side, tearing 

 up with it, no doubt, large quantities of matter from the bottom, and 

 loading the sea with mud and sand for more than a mile in all directions 

 from its bed. On the 27th of April, 1829, Mr. C. passed, in latitude 

 36° 10' north, longitude 39° west, near the middle of the Gulf Stream, 

 which there set in an east-south-easterly direction, an iceberg estimated 

 to be a quarter of a mile long, and from eighty to one hundred feet high. 

 It was much wasted in its upper portion, which was worn and broken 

 into the most fanciful shapes, forming resemblances of minarets, spires, 

 pyramids and castellated ridges, whose character was momentarily 

 changing by reason of the berg moving backward and forward horizon- 

 tally with great quickness. A strong breeze, and numerous smaller 

 fragments of ice floating in its vicinity, prevented a very near approach, 



