THE CLYDE SERIES OF SOILS. 13 
treme western portion of the area in Niagara County. As a result 
only small and scattered occurrences of the soils of the Clyde series 
are found. 
From the vicinity of Rochester, westward nearly to the eastern 
border of Niagara County, there are rolling plains and low rounded 
swells which show little or no evidences of having been covered for 
any length of time by- lake waters. These till areas contain no 
included deposits of soils of the Clyde series so far as the region has 
been mapped in detail. 
The country which rises southward from the 430-foot contour line, 
the approximate shore line level of the glacial Lake Iroquois, to 
altitudes of 1,000 or 1,100 feet is varied in its topography. At first 
the surface does -not materially differ from the lower plain. There 
are larger areas of the rolling swells of till, many drumlins in the 
eastern section, and a sharp break between the lower plain and the 
upper as the vicinity of Lockport, N. Y., is approached. There the 
lower plain is separated from a higher plain of very similar character 
and soil development by the first evidences of the rock-formed Ni- 
agara escarpment over which all of the waters of the Great Lakes 
pour at Niagara Falls. This escarpment first appears as a low ridge 
of limestone which becomes more elevated to the westward where it 
takes the form of cliffs or ridges. At its base lies the old shore line 
of Lake Iroquois, along its slopes and cliffs the bare rock outcrops, 
while at its summit the lake sediments again make their appearance 
and stretch for many miles to the southward, covering the greater 
part of the country west of the Genesee River and east of the Niagara 
up to an elevation of 800 feet above sea level. This higher plain is 
the area which was occupied by glacial Lake Warren and it forms 
an extension to the east of the glacial lake areas which were developed 
at about the same geological time in the Maumee Valley of Ohio and 
the Saginaw Valley of southern Michigan. 
The upper plain is much diversified in its surface slopes and drain- 
age features in western New York. The southern portion of Niagara 
County, the northern part of Erie County, and the adjacent portions 
of Orleans and Genesee Counties contain large areas of nearly level 
land with very slight depressions, which have been the location of 
former swamps, and within which considerable areas of the soils of 
the Clyde series have been accumulated. Other swampy areas have 
become the location of deposits of muck and peat. 
In the case of all of the larger areas of soils of the Clyde series 
in extreme western New York the surface is depressed below the 
general level of the surrounding soils, and the types of this series 
are poorly drained and darkened by accumulations of organic mat- 
ter only less in amount than is required to constitute muck soils. 
