182 Wisconsin Academy of Sciences^ Arts and Letters. 



an indication that the waters flowed west past the north end of Bhie island, 

 ,at the time when the bar was formed. 



The upper beach in Indiana presents a very different aspect except at the 

 immediate border of the two states from what it has in lUinois, for it is 

 composed mainly of sand, and the sand has drifted into prominent dunes 

 and ridges which have frequently an elevation of 25 feet or more above the 

 plains which lie south of them, and still higher above those on their north 

 face. The elevation of the plains which lie immediately south of the sand 

 xidges seldom exceeds 60 feet above Lake Michigan. It is evident, there- 

 fore, that the level of the lake was not more than 60 feet at the time of the 

 formation of this beach, though its dunes have sometimes an elevation of 

 80 feet above Lake Michigan. 



From Dyer, a sea cliff flanked by beach gravels passes nearly due east, 

 changing within two miles to a ridge of dunes. This ridge of dunes passes 

 through Schereville and extends east of this village about two iTiiles when 

 it quite suddenly terminates on a till plain in the east part of Sec. 13, Tp. 35 

 north, range IX, west. Tlie sand here apparently has drifted in a continuous 

 ridge a mile or more beyond the old lake border, for passing northwest to 

 the vicinity of Griffith, a distance of a mile or more, we find the lake 

 border marked by another line of dunes or rather a belt comjirising several 

 more or less continuous lines of dunes trending W. S. W., E. N. E. in the 

 same direction as the course of the Joliet division of the Michigan Central 

 railroad from Griffith to Lake — and thence along the main line of the 

 Michigan Central railroad for about five miles farther east. The belt is 1 

 and lA miles in width and lies almost entirely on the south side of these 

 railroad fines. Near Liverpool this belt is joined by the line of dunes which 

 represents the middle raised beach, and from this village eastward the two 

 branches are closely associated. Near the crossing of the Baltimore and 

 Ohio and Michigan Central railroads, a sudden deflection in the direction of 

 the dune ridges occurs. The whole belt comprising here four main ridges 

 and several smaller ones suddenly swerves from an E. N. E. to a nearly due 

 north course — and passes north to the Calumet marsh, at the border of 

 Avhich all the ridges suddenly terminate. North of this marsh the lower 

 beach ridges, or at least ridges which are quite continuous with those far- 

 ther w^est that are evidently later than the upper and middle beaches, oc- 

 cupy the interval between the present beach of the lake and the till tracts 

 which fie south of the system of raised beaches. We consequently find no 

 indications on the north side of Cahimet river, nor indeed in the portion of 

 Indiana east from there that these beaches remain, for the sands of the 

 lower beach conceal everything. In Michigan, however, we find traces of 

 the earlier beaches, some of which have been mentioned in the preceding- 

 chapter. The till ridge which lies east of New Buffalo, has gravel in indis- 

 tinct ridges at intervals on its western slope — the highest observed deposits 

 being about 60 feet above Lake Michigan. 



North of Galvin river in Sees. 36 and 25, Tp. 7 S. R. XXI W., is a beach 



