228 Proceedings 



to 200 individuals, was apparently above ground on the open space. 

 The ants showed great excitement and were running about in all di- 

 rections. Their actions appeared at first to be aimless, due to fear, 

 danger or some other cause that had thrown the whole colony in 

 commotion. But on closer observation it was seen that when two of 

 them met they would clasp antennae and forelegs and rise up on the 

 hind legs, would swing around two or three times, on which they would 

 separate, each one going in search for a new partner to repeat the 

 same action. 



The interpretation given to this unusual procedure was that the 

 ants were at play, or, to express it as man w^ould, they had a dance. 



248th Meeting, October 2, 1900. 



Ten persons present. 



Vice President Oestliincl presided. 



Program : 



The Geology of the Pembina Monntains, by C. P. Berkey, 



with specimens of brick made from their sand 



Glacial Plowing in the Vicinity of Minneapolis, by F. W. 



Sardeson. 



[abstract.] 



Th'is paper is based on a series of observations made during 

 excavation of Glacial drift. The results to date were shown by aid 

 of photographs. This paper with drawings instead of reproduced pho- 

 tographic illustrations has been published elsewhere. ("A Particular 

 Case of Glacial Erosion," The Journal of Geology, Vol. xiii, No. 4, p. 

 351-357, May-June, 1905.) 



249th Meeting, November 13, 1900. 



Thirteen present. 



Vice President Oestlund presiding. 



Program : Surface Features of Minnesota, by C. W. Hall. 



'fe.^ 



250th Meeting, December 4, 1900. 



About fifteen present. 



Vice President Oestlund presiding. 



Program^ : 



A demonstration of original micro-photographs as lantern 

 slides, showing the late progress in finer anatomy and in the 

 -physiology of the brain, by Harlow Gale. 



