Great Lakes, and their Deformation. 207 



or Forest Beach, is identical with that numbered four of the 

 Ohio Survey, at the head of Lake Erie. Spits and spurs are 

 frequently given off from these beaches, and add some difficulty 

 to the surveying, especially in Ohio. 



The Ridge way Beach, or next highest shore-line, is the 

 most important of the whole series, as it has been explored for 

 the greatest distance, and is perhaps the easiest of identifica- 

 tion. On it, many long stretches of dry roads, bounded by 

 muddy plains, have been used from the first settlement of the 

 country. The other ridges have also in places been used for 

 roads, but to a less extent. 



Elevations on the Llidgeway Beach determined hy Leveling. 



Feet above the Sea. 



Lake Michigan and Lake Huron 582 



Lake Erie 573 



Beach near Chicago (calculated) 526-542 



Near Columbia, Mich 618 (bar.) 



Allegan (terrace) in valley 643 



Grands Rapids . _ _ _ 670 



Pewamo 724 



Chapin 760 (bar.) 



East of Emmett 770 



Near Berville 753 



East of Ypsilanti - _ . 734 



West of Lenawee Junction 735 



Defiance, Ohio 738 (Gilbert.) 



Cleveland 743 (Geol. Ohio.) 



Madison 740 (bar.) 



Sheridan Centre, K Y _ 834 (Gilbert.) 



Hamburg, N. Y 870(+ or —20) 



(Gilbert.) 



Throughout the windings, this coast line has been explored 

 for eight or nine hundred miles. The highest beach south of 

 Chicago is only 42 feet above the lake, and this probably belongs 

 to a series to be noted hereafter, and from it the position of the 

 llidgeway Beach is calculated. The country southeast of Lake 

 Michigan is very sandy and duny, and thus it is more difficult 

 to recognize the exact water-margins than farther east where 

 the beaches are narrow ridges between clay plains. From 

 Grand Rapids to Pewamo the beach passes through a strait 

 between high lands on both sides. This depression is now 

 occupied by the Grand River, between the head waters of 

 which, and those draining into Saginaw Bay, the divide does 

 not exceed a height of one hundred feet above the lakes, 

 although the land rises many hundred feet on both sides, 

 Indeed, from even west of Pewamo the low embayment widens 



