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March 7, 1849. 

 The President in the Chair. 



Present, twenty-five members. 



Dr. C. T. Jackson exhibited to the Society specimens of 

 gold ore from the Virginia mines, containing the rare min- 

 eral Tellurium in the form of a Telluret of lead and gold 

 with a little silver, and a small amount of Silenium. These 

 minerals. Tellurium and Silenium have never before been 

 found in America. With some of the specimens Bismuth 

 is found, a rare combination. The form, however, in which 

 the ore is brought from the mines makes it difficult to say 

 whether it is actually combined or only mixed with it. 



Dr. Jackson presented, in the name of Elie de Beaumont, 

 a monograph, entitled " Note sur les Systemes de Montagnes 

 les plus anciens de I'Europe, par M. L. Elie de Beau- 

 mont, and gave a general account of its contents. 



Prof. Rogers said he wished to present for the considera- 

 tion of the Society some views of his own with reference 

 to a certain peculiarity in the structure of Glaciers as he 

 saw them in Switzerland, which had not been before 

 explained. 



The general structure of Glaciers, as has been pointed out by 

 Agassiz, Forbes and others, is looped ; presenting a series of 

 concentric curves bulging downwards, extending across the 

 Glacier. Agassiz has determined that the middle of the Glacier 

 moves the fastest, and has shown that these loops are caused by 

 the closing up of fissures. The ice in fact presents in a fixed 

 shape the conditions impressed on a current of water. Prof. 

 Rogers said there was another looped structure, not so readily 

 explained, which had come under his notice. About the end 

 and on the edges of the Glacier the ice is in a condition of cleav- 

 age very much like that seen in a slate quarry. This appear- 



