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 southwest ward 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 t}^pe 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- 
ing 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 
