SOIL SURVEY OF PORTER COUNTY, INDIANA. 17 



and marshy, undeveloped land is valued at less than S50 an acre, but 

 the majority of the farmers value their land, with improvements, at 

 $100 to $150 an acre, and some farm land is held for more than $200 

 an acre. 



SOILS. 



The soil materials of the Porter County, Ind., area were accumu- 

 lated by various glacial processes. As shown in the opening chapter, 

 the northwestern part of the county is underlain by materials ac- 

 cumulated by deposition in lakes, the southeastern part by deposi- 

 tion from rmming water and mcidental standing water and the 

 central part by deposition from glacial ice. In the northwestern 

 and southeastern parts, therefore, the material consists usually of 

 sandy clays, silts, clays and sands, while across the central part of 

 the comity it consists predominantly of bowlder clays. The bed- 

 rock consists of limestone, but it is so deeply buried by the various 

 deposits just mentioned that it is not a factor in the determination 

 of the character of the soils of the county. The material from which 

 they are derived consists of a mixture of clay, silt, and sand presum- 

 ably derived from the same or similar sources as the gravel and bowl- 

 ders occurring with them, which consist of granite and other crystal- 

 line rock fragments, shale, sandstone, and Umestone. It is therefore 

 heterogeneous in its mineralogical composition as well as in its 

 physical constitution. It is from tliis material that the soils of the 

 county have been developed by weathering and by local redeposition. 



The soils have developed m a humid region where in part of the 

 area the natural surface drainage is good and in part it is deficient, the 

 former condition being characteristic of a large part of the central 

 belt of ice-laid material, the latter of a considerable part of the smooth 

 areas in the northwestern and southeastern parts of the county. The 

 soils of the whole county, therefore, because of the humid conditions 

 mider which they have developed, are leached of their readily soluble 

 salts, and the carbonates, consistmg of the limestone fragments in the 

 parent material, have been ehminated to a depth of several feet; only 

 in a few cases is any left within the 3-foot profile to which examination 

 is extended. The soils on the rolling lands have been oxidized and 

 aerated to a depth of several feet as a rule. Those with light texture 

 or underlain at relatively shallow depths by gravel or sand, occurring 

 within the area of flat or very smooth topography, have in most cases 

 reached the same stage in their development. 



The rest of the soils on the flat land areas have developed under 

 conditions of excessive moisture. They are, as a rule, somewhat less 

 thoroughly leached of their lime carbonates and are imperfectly 

 oxidized and aerated in their subsoils, the extent of these changes 

 varying in the various types. 

 34658°— 18 3 



