2 BULLETIN 142, U. S. DEPARTMENT OP AGRICULTURE. 



The soils of the Miami series do not occupy all the territory within 

 which they are developed. In addition to these soils, and closely 

 associated with them in the lower peninsula of Michigan and in 

 portions of central Wisconsin, are those of the Coloma series. The 

 latter are distinguished by light-brown to gray surface soils, yellow 

 or reddish subsoils, and by their derivation from noncalcareous ma- 

 terials. They are prevailingly more gravelly and sandy than the 

 soils of the Miami series. 



Throughout all of the more nearly level areas occupied by the 

 Miami soils there are large and small areas of soils which have dark- 

 gray or nearly black surface soils and gray, drab or mottled sub- 

 soils. These soils are classed in the Clyde series, and are distin- 

 guished by the large quantities of organic matter which have accu- 

 mulated in the surface soil. They occupy areas in which obstructed 

 drainage gave rise to small ponds, or to swamps. They occur in 

 the depressions and level areas lying between the low swells and 

 ridges occupied by soils of the Miami series. 



Toward the western boundary of the Miami series these soils are 

 associated with dark-brown or black soils, which are classed as the 

 Carrington series. Originally the Carrington soils were mainly 

 prairie. They are of glacial origin, and usually calcareous in the 

 subsoils, but are distinctly and uniformly much darker in color 

 than the soils of the Miami group. 



In nearly every area in which the soils of the Miami series are 

 encountered there are also found extensive areas of water-worked 

 and stratified soils of glacial origin which were deposited either as 

 terraces along streams issuing from the melting ice or in the form 

 of nearly level outwash plains of varying size. Several different 

 series of soils have thus been formed. They are all distinguishable 

 from the soils of the Miami series through the presence of stratified 

 beds of sand and gravel at or near the surface and through the pre- 

 dominance of gravelly and sandy soils. 



GEOGRAPHICAL DISTRIBUTION. 



The soils of the Miami series occur most extensively in the west- 

 ern part of Ohio, the central and northeastern part of Indiana, in 

 southern Michigan, south of a line connecting Bad Axe and Muske- 

 gon, in the Traverse Bay region of Michigan, in extreme north- 

 eastern Illinois, throughout eastern Wisconsin, and in a portion of 

 the upper peninsula of Michigan, adjoining Green Bay. The loca- 

 tion of the Miami series of soils is shown in figure 1. 



The eastern boundary of the region dominated by the soils of the 

 Miami series extends southward from the vicinity of Tiffin, Ohio, 



