1 54 Association of Amei-ican Geologists and Naturalists. 



regard to the bowl-shaped cavities, encircled on all sides by regu- 

 lar hills, he suggested that they might have been worn by the 

 rotary motion of icebergs ; this rotary, or semi-rotary motion of 

 the icebergs, he had noticed both in those which were and were 

 not stranded. They become gradually worn away on one side 

 by the action of the water, when they turn over with a displace- 

 ment of the sea, and violent upheaving of the mud and sand, ren- 

 dering the water turbid to a great distance. 



The discussion was continued by Mr. Lyell and Mr. Coiithouy, 

 on the probable agency of icebergs in diluvial phenomena, and 

 especially in regard to the water-worn cavities or pot holes. 



Dr. C. T. Jackson described the pot holes which occur in 

 Orange, near Canaan, in the elevated land between the Connecti- 

 cut and Merrimack rivers in N. Hampshire. They are worn in a 

 hard granite-gneiss, in a line following the general N. and S. di- 

 rection of the diluvial or drift current. One which had been clear- 

 ed of the round smooth stones which formerly filled it, and which 

 is known to the inhabitants as " the well," is eleven feet deep, 

 four and a quarter feet wide at the top, and two feet at the bottom. 

 These pot holes could not be referred to the action of any exist- 

 ing current of water, as they are on the water-shed line, between 

 the two rivers, and more than one thousand feet above the sea 

 level. 



Mr. John H. Blake was requested to prepare a paper on the 

 tertiary and drift of the Andes. 



Prof. H. D. Rogers remarked in relation to stranded icebergs, 

 that coming from the north, loaded with bowlders, and stranded 

 far above the sea level, they would, while melting, produce all 

 the phenomena of the glaciers of the Alps. 



Mr. Coiithouy was requested to draw up a paper, embracing 

 the facts which he had collected in regard to icebergs, to lay be- 

 fore the Association. Mr. C. having, in accordance with this re- 

 quest, prepared the following summary of his observations and the 

 remarks he had made concerning them, at the present session, it 

 is here inserted. 



Mr. C. premised that in order to give the remarks he was about to 

 submit, their full weight, it might be proper for him to state, that he had 

 no preconceived opinion — no hypothesis of his own upon this question, 

 to sustain. His intention was simply to offer a few facts which had 

 fallen under his personal observation, with the inferences to which they 



