Raised Beaches of Lake Mich i<jrni. 191 



interval between this beach and the lake is much uarrcSwer than in Lake 

 county. These minor beach lines are but a few feet .in height, and 6— 10 

 rods in width. At their western ends they are lost in the sandy plain 

 which borders Wolf Lake, Lake Calumet and other small lakes near th& 

 state line or the borders of Lake Michigan. It is probable that these beach 

 lines have each in turn shut off portions of the lake lagoons, and thus 

 made encroachments upon it. They were probably built up as bars, work- 

 ing their way westward along the coast, for the shore currents at the 

 present day are carrying sand across the south end of the lake in a west- 

 erly course, and building up broad branches at the head of the lake. 



By reference to the Illinois beach lines it will be seen that from Chicago 

 south, the beach which formerly bore west of south to Englewood, has by 

 gradual accretions along its eastern border, been built out several miles to 

 the eastward. The shore currents on the west side of the lake are south- 

 ward, and consecjuently they unite with the westerly currents on the soutii 

 shore to build u^:) a broad beach at the head of the lake; near the state Une 

 between Illinois and Indiana. Between the western ends of the low 

 beaches in Lake county, Indiana, and the southern ends of the beach lines 

 near Englewood, in Illinois, is a low sand- covered tract occupied by sev- 

 eral small lakes, and nowhere rising to the height of the beach lines, much 

 of it being scarcely five feet above the level of Lake Michigan, This was 

 apparently an open bay at the time these bar-like beaches were forming, 

 but has now become filled Avith sand, leaving Lake Calumet and other 

 lakelets and ponds as remnants of its waters. 



The shores of the lake at the iDresent day are not stationary. In one 

 place encroachments are made upon the bordering shores while in adjacent 

 portions of the shore accretions and accumulation is going on. Thus from 

 Waukegan to Evanstou, Illmois, the bluffs are undermined and removed 

 at a rapid rate, but from Evanston, south to the head of the lake, the ac- 

 cumvilation along the beach is greater than the removal. On the opposite 

 side of the lake from Langatuck, Michigan, to a point on the shore some 

 ten miles southwest from Micliigan City, Indiana, the I'emoval is greater 

 than the accumulation, but as is shown above, the accumulation exceeds 

 tlie removal along the remainder of the south shore. The projecting points 

 along the lake are undermined more rapidly than the heights, so that the 

 lake tends toward a more regular outline by its erosive power, and as we 

 have seen above the bay-like elongation at the head of the lake has been 

 greatly reduced smce the epoch of the main lower beach, so that the lake 

 is also tending toward a smoother outline by its depositing power. 



The lower beach in Indiana is composed mainly of sand — gravel being 

 found only in its deeper portions. The sand has drifted into dunes through- 

 out the entire length of the beach lines in this state — so that elevations 

 taken along the crest of the main ridge do not show the height at which 

 the lake stood during its formation. B\' aneroid determinations there is a 

 range of more than 50 feet in the elevation of this crest, some portions be- 



