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. 



