Icebergs iqjon Drift. 439 



II. As the aqueo-glacial theory of drift supposes the ice- 

 bergs of the ancient seas to have been agents of enormous 

 power, we may judge of the probability of these conjectures 

 by inquiring as to the magnitude and form of those found 

 floating in our present oceans. 



Those which come from Baffin's Bay, although often of 

 great height, appear to be of less extent than those seen south 

 of the equator. Captain Crocker, of New Bedford, measured, 

 with his sextant, one which was aground upon the Banks of 

 Newfoundland, and found it to be two hundred and forty-four 

 feet in height, and half a mile in length. Parry counted from 

 his deck, at one time, no less than one hundred and three ice- 

 bercfs, some of them from one to two hundred feet in height. 

 Captain Ross, in Baffin's Bay, saw seven hundred in sight at one 

 time, and several aground together, in 250 fathom, 1500 feet. 

 Those found in the Southern Ocean are of vast dimensions. 

 Several have spoken to me of icebergs which they judged to be 

 three or four miles long. Captain William Beck, of New 

 York State, informed me that, in 1835, in latitude 46"", he 

 saw an iceberg which must have been from five to ten miles 

 long. His own impression, and that of the master of the 

 ship, was that it was no less than ten miles in length ; when 

 they first saw it, they supposed it to be land. They were an 

 hour and forty minutes in sailing by it with a good wind. 

 Mr. Fernald and Mr. Curtis saw one near South Georgia 

 which they judged to be from ten to fifteen miles in length, 

 as they were several hours in rowing by it in a six-oared boat. 



The estimates, made without actual admeasurement, cannot 

 be much relied upon, although I am inclined to think those 

 given by my informants have been rather within, than beyond 

 the truth. It will be interesting to refer to admeasurements 

 carefully made by the officers of the French Exploring Expe- 

 dition. I found that ten icebergs, whose dimensions were 

 given in one of the charts accompanying the account of the 

 Expedition of the Astrolabe, were between 90 and 150 feet 

 in heii^ht. Four were between 180 and 225 feet in heif^ht. 

 Sixteen, which, with two exceptions, were over 100 feet 



