THE MIAMI SERIES OF SOILS. 23 



The surface configuration of the Miami fine sandy loam varies 

 widely. The type generally occupies the rolling to hilly upland 

 areas which mark the location of old glacial moraines. The topog- 

 raphy ranges from rolling to ridged, with many small intervening 

 depressions and inclosed basins between the ridges. The Miami fine 

 sandy loam is comparatively thin over the ridges, frequently becom- 

 ing thicker along the lower slopes and in the more nearly level areas. 

 It is particularly well developed in the rolling to hilly belt which 

 extends from the " thumb " of Michigan southwestward to the Ohio- 

 Indiana State line. It also covers portions of the low moraines in 

 central Michigan, from the vicinity of Lansing west and north 

 nearly to the shore of Lake Michigan. 



In south-central Wisconsin the topography of the Miami fine sandy 

 loam is generally undulating to rolling. The type occupies low 

 morainal ridges, undulating till plains, and some nearly level mar- 

 ginal areas. In extreme northern Wisconsin a large area of the 

 type found in Marinette County is nearly level to only slightly 

 undulating. 



In general, the natural drainage of the Miami fine sandy loam is 

 good. Where the depth of the surface sandy material is 2 feet or 

 more, especially if the surface slopes are at all steep, there is a tend- 

 ency toward droughty conditions. This is also true on the narrow 

 crests of morainal ridges and in other places where erosion has 

 exposed the underlying gravelly or stony material. These areas, 

 however, are of comparatively small extent and over the greater part 

 of the type the texture and depth are favorable to the absorption 

 and retention of sufficient moisture for the production of the staple 

 crops of the region. Some of the small, depressed, kettle-shaped 

 areas of the type are rather poorly drained and are subject to the 

 accumulation of drainage and seepage waters from higher areas of 

 the type. These are the only areas in which the need for artificial 

 drainage is great. 



The Miami fine sandy loam has been formed by the weathering 

 of glacial till. It is probable that the surface material has been 

 assorted and modified to some extent through the melting of glacial 

 ice, but in almost all instances the deeper subsoil consists of unmodi- 

 fied glacial till. This material has accumulated in long, irregular 

 ranges of morainal hills, in low, undulating swells, and in the form 

 of nearly level but somewhat irregular, dimpled till plains. The 

 material entering into the composition of the Miami fine sandy loam 

 consists largely of the local country rock, which in a majority of cases 

 comprises limestone, sandstone, and shale mingled with a varying 

 amount of the debris of crystalline rocks brought to the region dur- 

 mg the period of glaciation. It is a common characteristic of the 

 type that a large part of the finer gravel and even some of the coarser 



