296 DENUDATION OP THE LAND. Chap. VI. 



observed. In a fourth case, the mould iu a 

 furrow in the upper part of a sloping field 

 was 2^ inches, and in the lower part 4| 

 inches in thickness. 



On the Chalk Downs at about a mile dis- 

 tance from Stonehenge, my son William ex- 

 amined a grass-covered, furrowed surface, 

 sloping at from 8° to 10°, which an old shep- 

 herd said had not been ploughed within the 

 memory of man. The depth of one furrow 

 was measured at 16 points in a length of 68 

 paces, and was found to be deeper where the 

 slope was greatest and where less earth would 

 naturally tend to accumulate, and at the 

 base it almost disappeared. The thickness of 

 the mould in this furrow in the upper part 

 was 2J inches, which increased to 5 inches a 

 little above the steepest part of the slope ; and 

 at the base, in the middle of the narrow 

 valley, at a point which the furrow if con- 

 tinued would have struck, it amounted to 7 

 inches. On the opposite side of the valley, 

 there were very faint, almost obliterated, 

 traces of furrows. Another analogous but 

 not so decided a case was observed at a few 

 miles distance from Stonehenge. On the 



