THE CLYDE SERIES OF SOILS. 15 



have been traced accurately through northern Ohio, northeastern 

 Indiana, and southeastern Michigan. 1 



The lower limit of the glacial lake sediments which were formed 

 in this basin is at present marked by the shores of Lake Erie and 

 of the St. Clair Kiver, Lake St. Clair, and the Detroit River. This 

 lies at an altitude of about 575 feet above sea level. The highest 

 limits of occupation by the glacial Lake Maumee are found to be 

 approximately 775 feet above tide in the vicinity of Fort Wayne, 

 Ind., about 800 feet in the southeastern counties of Michigan, and 

 ranging from 750 to 800 feet above sea level in north-central Ohio. 

 There is thus a total difference of present elevation of the surface 

 of these glacial lake deposits not exceeding 225 feet. The Maumee 

 Basin thus presents a very gently sloping surface which is inclined 

 from the level of the shore lines toward a central axis extending 

 from Fort Wayne, Ind., to Toledo, Ohio, with a gentle slope to- 

 ward Lake Erie along the line of this axis. The slopes are so 

 slight over any limited area that it is difficult to determine their 

 direction except by the aid of leveling instruments. The stream- 

 drainage ways are deeply cut along the major streams but follow 

 mere shallow trenches so far as the majority of tributaries are con- 

 cerned. The Maumee River has cut its channel to a depth of 15 to 

 60 feet, frequently encountering bedrock. The smaller streams have 

 cut their courses from 10 to 40 feet below the level of the plain. 



The general surface of the lake plain in the Maumee Basin is 

 but slightly undulating over the upland between the drainage ways. 

 Low swells and ridges rise to altitudes of 5 to 20 feet above the 

 lowest points in any given locality. There are also low moraine 

 ridges of somewhat greater elevation which probably rose above the 

 level of the ponded lake waters. The Defiance moraine in the ex- 

 treme northwestern counties of Ohio thus separates all of the basin 

 lying in Allen County, Ind., and a large part of the lake sediments 

 found in Defiance, Paulding, and Van Wert Counties, Ohio, from 

 the remaining area of the Maumee Basin. 



Below the highest shore line of the glacial lake waters there are 

 usually two or more other shore lines existing as concentric ridges of 

 gravelly and sandy material frequently separated from each other 

 by sandy loam or loam deposits. Elsewhere through the Maumee 

 Basin the greater part of the surface consists at present of the dark- 

 brown or black clay loam or clay soils of the Clyde series. 



The chief exception to this rule is found along the immediate banks 

 of the Maumee River and its principal tributaries where erosion has 

 removed the shallow lake deposits, exposing the underlying till in 

 the form of yellow or brown clay loam soil, classed with the Miami 



1 Glacial Formations and Drainage Features of the Erie and Ohio Basins, U. S. Geol. 

 Surv. Monograph No. XLI. By Frank Leverett. 



