THE GLACIAL LAKE CHICAGO. 431 



but not infrequently a series of parallel ridges occur, separated by narrow 

 sags. 



The effect of the waves at this lake stage is discernible on the borders 

 of Blue Island till ridge, though the western border is characterized by- 

 dunes which conceal to some extent the action of the lake. 



The beach enters Indiana near Dyer and passes eastward through the 

 center of the village. It stands about 10 feet above the plain bordering it 

 on the north and is 30 to 40 rods in width. Within 2 miles east of Dyer 

 it reaches a height of 25 or 30 feet, there being wind-drifted sand along its 

 crest. Eastward from there to a point about 1 h miles east of Schererville it 

 maintains a height of 20 to 30 feet and width of 40 to 60 rods. It then 

 curves toward the northeast and dies out in less than a mile. Continua- 

 tions are, however, found in the district to the north. About a mile north 

 from its east end a small ridge sets in, which leads eastward, passing' south 

 of Griffith. A larger ridge sets in on the south side of Cady Marsh west of 

 Griffith and leads eastward through that village. It soon becomes a belt of 

 sand one-half mile or more in width, with several parallel ridges, and this 

 belt extends in a course north of east through Ross, Liverpool, and Chrisman, 

 and comes to Calumet River about 2 miles northeast of Chrisman. The 

 Second or Calumet beach is closely associated with it from the vicinity of 

 Ross to Chrisman. From Calumet River the two beaches lead northeastward 

 nearly parallel with the present shore of Lake Michigan, and distant 2 to 3 

 miles from it, to Trail Creek near Michigan City, beyond which there is 

 considerable complexity, as shown below. 



The belt of sandy ridg-es whose course has just been outlined appar- 

 ently did not form the extreme southern limits of Lake Chicago, but 

 inclosed or shut in bays of considerable size on the south border. One of 

 these bays extended south into the Deep River Basin several miles beyond 

 the sand belt, its south border being 2 or 3 miles south of Hobart. From 

 this bay there was apparently a westward connection with the lake along 

 the valley of Turkey Creek between a till ridge noted above and the north 

 border of the Valparaiso morainic system. In places a cut bank 3 to 5 feet 

 high has been formed on the slopes of these bordering moraines. 



Another bay was formed in the Salt Creek drainage basin, which 

 extended 3 or 4 miles south of the belt of sand ridges. This was separated 

 from the bay in the Deep River Basin by the till ridge which leads north- 



