570 PROCEEDINGS OF NEW YORK MEETING. 



17. 16 by 25 feet in diameter. The wall between it and no. 13 stands up 1 feel 

 above the filling, with a thickness of only '2 feet. 



18. <i by 1<> feet in diameter ; 2t5 feet southwest of and 10 feet higher than no. 5. 

 \ 19. The west wall rises 30 feet. 



20. 5 feet in diameter, and it- wall rises 3 to I 



The Twin pot-holes are situated near the edge of :i cliff of rock and about 20 to :;<> 



feet below the- summit of the mountain, and are im diatcly west of and about 60 



>ve pot-hole no. 17 in thi ;ml; list. The two holes art round and smooth 



and 6 to 7 feel each in diameter. In going down they join :it a depth of 1<» to r_! 

 feet, and within :i yard or so of the earthy bottom. About the point where the two 

 join, the one on the south side has broken an opening "_' to 3 feet by I to •"> feet in 

 diameter out into the face of the steep cliff. I descended to the bottom with a sharp- 

 ened pole and forced it down into the soft peaty bottom several feet without reaching 

 the .-olid rock. 



Pot-hole mountain is composed of a dark green hornblende rock, with a small 

 percentage of greenish white feldspar. It is hard and tough, and shows a fibrous 

 structure It form- one of c 1 i «- strata of the green Hurouian schists which occupy the 

 locality. These strata dip to the N. N. W. at a high angle. 



The surface of the surrounding country is rough and rocky by reason of the numer- 

 ous coalescing valley.-, with oblong hills often steep and bare, and rising 50 to over 

 200 feet above them. The general level of the bottoms of these valleys rises irregularly 

 ha<d< from Lak>- Superior, and gains an elevation of probably 300 feet at Pot-hole 

 lake. Pot-hole mountain is one of the highest knobs in the locality. It is surrounded 



by a deep valley near by, and in the distance by similar knobs and vallej -. es| ially 



toward- the northwestward, the direction from which the stream that produced the pot- 

 hide- seems to have flowed. When this stream was in action the valleys to the northwest- 

 ward must have been filled with rock, earth, or ice to carry the stream. Since then 

 the locality has heen eroded and a vast amount of material Bwept away. I n oik 

 horizontal glacial grooves may be -ecu on a portion of the elevated, vertical wall 

 .if the pot-hole. The action of the water is evident everywhere. 'I show 



at higher elevation- than Pot-hole mountain, in the neighborhood and along Lake 

 Superior. 



[n conclusion, J would Btate that it seems to me that the current- that produced 

 these pot-holes existed prior to the ChampTain or even the close of the Drift epoch, if 

 not pri<>r to the beginning of the latter. 



The retiring President, Professor .lame- Hall, gave a farewell addr< 

 The Society then adjourned to meet al [udianapolis on Tuesday, August 19, 

 L890, al Mi A. M. 



