18 



FIELD WORK. 



Selection of Fields. 



The three types mentioned above, viz.. the Carrington silt loam, 

 an upland prairie type, the Fargo silt loam, a lowland prairie type, and 

 the Carrington loam, a forest type, were selected for study on both 

 drifts. 



The fields selected to represent these types on the Kansan are 

 located in the township of Wheeling in the eastern part of the county 

 with the exception of one just over the north line of this (Fig. 3). The 

 fields of Carrington silt loam and Fargo silt loam sampled on the Late 

 Wisconsin are in the townships of Warsaw and Morristown in the 

 southwestern part of the county, while those of Carrington loam on this 

 drift were selected in the townships of Walcott and Cannon City, none 

 l)eing far distant from the city of Faribault. 



The Marshall silt loam, a type developed upon loessial material 

 derived entirely from pre- Wisconsin drifts and confined to the Kansan 

 side of the dividing line, was studied in addition to the three, just men- 

 tioned. 



In selecting the individual fields it was the aim to secure those in 

 as nearly. their virgin condition as it was possible to obtain them. This 

 is e.xtremely important since, as has recently been pointed out by Glinka 

 (16 p. 96), the formation of soil horizons which are within reach of 

 the plow is not uncommon. Not a single entire field of upland prairie 

 was found. So, in the case of the Carrington silt loam the task of 

 locating suitable tracts from which to take samples was difficult. Prac- 

 tically all the samples taken on this type were from along line fences or 

 beside roadways which it seemed certain had never been plowed. Since 

 they were so easily brought under the plow it is not surprising that 

 entire fields still in an actually virgin condition on this type are no 

 longer to be found. At the time of the field work a few of the original 

 settlers were still living and these were able to give much valuable 

 information. Each field was selected only after the oldest settlers in 

 the neighborhood had been consulted and a more or less complete his- 

 tory of the field had been obtained. Thus in the case of one field, IV, 

 on the Marshall silt loam it was found that an old settler living within 

 half a mile of it had cleared off the brush and plowed the adjacent field 

 in 1858 and had seen it every year since. 



In the case of the Fargo silt loam virgin fields were not so difficult 

 to find. On the Kansan, two rather poorly drained meadows, both of 

 which were plowed a few days after the samples were taken, formed 

 two of the fields, the grassy roadsides two others, and a line fence 

 border the fifth, while on the Late Wisconsin all were from line fence 

 borders or beside roadways. 



