GEOLOGICAL AND NATURAL HISTORY SURVEY. 75 



or Other accurate data showing its former extent. The bar is pre- 

 served from the Douglas monument southward to Englewood, a 

 distance of four or five miles. This portion consists of a series of 

 overlapping ridges, of which the westernmost or earlier terminate 

 further north than their successors on the east. At the termination 

 of each of these ridges a hook turns out to the west into the bay 

 that was inclosed by the bar. An outlet seems to have been main- 

 tained toward the Des Plaines around the southern end of this 

 bar, until it reached Englewood. This may not have been closed 

 until the water level had dropped too low for a discharge to the 

 Des Plaines. 



Passing across the outlet marsh from Englewood to South 

 Lynne, a continuation of this beach is found. It leads in a course 

 east of south to South Englewood and thence more easterly across 

 the northwest corner of Calumet Township into Hyde Park, com- 

 ing to the Illinois Central Railway a short distance north of Pull- 

 man. From this point a gravelly ridge is traceable southward 

 past the north border of Lake Calumet, where it dies out in the 

 marsh. A slight beach is formed to the northeast from here on 

 Stony Island, between Lake Calumet and South Chicago. But the 

 main line of this beach is found west of Lake Calumet, running 

 north and south through the west parts of Pullman and Kensing- 

 ton, where it usually has the form of a cut terrace, with banks lo 

 to 15 feet in height, but changes to a gravelly and sandy beach at 

 the south. This beach comes to the Calumet River at Riverdale, 

 where it connects with the Sag outlet. It reappears on the south 

 side of the river at Dolton and passes thence southeastward into 

 Indiana. Its course in Lake County, Indiana, is eastward through 

 Hessville and Tolleston and Miller. In Porter County it continues 

 with a slight deflection to the north, keeping parallel to the shore 

 of Lake Michigan, and enters LaPorte County near the south edge 

 of Michigan City. A short distance northeast from Michigan City 

 it becomes merged with the dunes of the present shore, and no 

 attempt was made to separate it beyond that city. 



The Illinois portion of this beach consists mainly of fine 

 gravel, which is usually well worn, but in places has considerable 

 angular material, as if formed rapidly and subjected for but a brief 

 period to the action of the lake waves. The low district along 

 the Chicago River back of this beach has received quite generally 

 a coating of sand several feet in depth, and the marshy tracts in 

 Hyde Park and Lake Townships are also covered with sand to a 



