REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1900 rill 



The expectation of finding a repetition of the 27 foot interval 

 both north and south, or of a space corresponding to it, is not 

 fully met. Northward such interval is wanting except in profile 

 25, which has two groups oi bars, the interval between the crests 

 of the two groups being 37 feet. On the south the next profiles 

 (nos. 13, 14) have a clear interval of 35 feet, which is too great;, 

 but profiles 5 to 12 do suggest a northwardly increasing interval 

 in accord with the Adams bars (nos. 15 to 17) and with no. 25. 



These figures of the third column of the table give the best 

 showing that can be found for a northward increasing interval 

 between the bars. Taking profiles 5 to 12, 16 and 25, an increase 

 of about 1 foot a mile can be figured out. But this omits from 

 consideration the profiles with a regular siuccession of bars, as 

 nos. 4^ 18, 21 and 24; also those which show no lower bars, though 

 the range is sufficient, as nos. 2, 3, 22 and 23. The negative evi- 

 dence seems quite as strong as the affirmative, specially since the 

 latter rests only on a few selected profiles. 



If there had been a spreading apart of the two upper bars 

 toward the north of 1 foot to the mile, it would seem as if the 

 spreading throughout the whole range of the bar formation should 

 certainly be evident in column 4 of the above table. The evidence 

 here is decidedly negative. The best that can be said regarding 

 the suggestion of northward differential uplift during the life of 

 Lake Iroquois is that it is not yet proven. 



Time of land warping 

 The vertical distance between the upper and the lower bars, 35 

 to 40 feet, is supposed to be more than the depth of water limit- 

 ing the formation of sandbars, this depth being taken as about 

 30 feet. The inference is that the great vertical range of the 

 bars was proiduced by subsidence of the water level. The distri- 

 bution of bars at all levels throughout the vertical range suggests 

 a slow subsidence. It seems probable that the lowering was 

 caused by the down-cutting of the outlet of the lake at Rome 

 N. Y., and not by the tilting of the basin. The warping of the 

 region has apparently occurred since the extinction of Lake Iro- 



