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 River, 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.j 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. 
