20 



EXPERIMENTAL. 



A. Relative Fineness of Texture. 



When taking samples the fragments larger than 2mni. in diameter 

 that were hrought up by the auger were included in the sample. In 

 cases where a pebble an inch in diameter or larger obstructed the way a 

 new boring was made. No attempt was made to ascertain the amount 

 of coarse gravel or of rock fragments of still larger size. On glaciated 

 areas such as these this would vary considerably from place to place 

 and its determination would involve the handling of large amounts of 

 soil and subrjil in the field. 



1. Proportion of Coarser Fragments. 



The J percentage of the coarser material, as above defined, and the 

 average \/eight of the fragments (Tables 5 to 12) were determined in 

 all the field samples. These data also serve as a rough index of the 

 varying amounts of coarse gravel and boulders present in the different 

 sections and on the two drifts. 



Carrington Silt Loam. On the Kansan (Table 5) the average per- 

 centages found for the three foot section in the different fields are very 

 similar, while the differences between the amounts found in the corre- 

 sponding sections are small, the maximum being found, as would be 

 expected, in the third foot-section. The average for all sections of the 

 5 fields is o.51 per cent. 



Table 5. — Coarse grat'el in the different sections from the five fields on Car- 

 rington silt loam. 



Depth 

 Inches 



1— 6 



7—12 

 13—24 

 25-36 

 Average 



1—36* 



1— 6 



7—12 



13—24 



25—36 



Average 



1—36 



Field 



I 



per cent 



0.06 

 0.04 

 0.13 

 1.08 



0.42 



0.17 

 0.51 

 1.32 

 1.94 



1.20 



Field 



II 



per cent 



0.52 

 0.68 

 0.37 

 0.77 



0.58 



Field 



III 



per cent 



1. Kansan. 



0.23 

 0.33 

 0.31 

 1.15 



0.55 



Field 



IV 



per cent 



0.15 

 0.21 

 0.13 

 1.06 



0.46 



2. Late Wisconsin. 



1.18 

 1.08 

 0.91 

 2.85 



1.63 



1.00 

 1.25 

 2.83 

 3.44 



2.46 



1.03 

 1.38 

 1.91 



2.59 



1.90 



Field 



V 



j>er cent 



0.12 



0.50 

 0.14 

 1.15 



0.53 



0.99 

 0.98 

 2.38 

 4.32 



2.56 



Average for 



5 fields 



per cent 



0.22 

 0.35 

 0.22 

 1.04 



0.51 



0.88 

 1.04 

 1.87 

 3.03 



1.95 



*To secure the averages for the 3 foot-sections the percentages from the two 6-inch 

 sections were averaged and this result, in turn averaged with the percentages for the two 

 lower sections. This procedure was followed for all tables reported hereafter. 



