188 On the Origin of the Terraces, Ballcs, or Lynchets 



a slight trench, sufficient however to stop the silt washed down 

 from above, which consequently would accumulate there in a bed 

 perhaps only an inch or two in depth. But in the next year or 

 next ploughing, the process is repeated ; the cultivator again 

 checks the descent of silt by a double boundary furrow, or the 

 same effect is produced by the slight edging of earth or grass which 

 forms the lower limit to the action of the plough. And thus by 

 degrees a slight bank of earth is formed which in the progress of 

 years increases into a " lynchet " or " balk," i.e. a steep grass- 

 grown bank, several feet in height, with a somewhat flattened 

 terrace above — separating the parallel strips on a hill-side in the 

 hands of distinct cultivators. Or, indeed, the same result may be 

 purposely produced by the same cultivator, occupying the whole 

 slope, and desirous of stopping the wash of soil down to the bottom 

 of the valley by forming some artificial checks of this kind to it, 

 in the manner of the terraces so laboriously formed by the vine- 

 cultivators of southern Europe. 



This is not mere theory. I have often watched the growth of 

 such banks, and even witnessed their formation from the beginning. 

 It is noticeable indeed with what rapidity they are produced and 

 increased year by year. For example I have seen one from two to 

 three feet high formed in the course of ten years at the foot of a 

 steep slope first broken up from old pasture at that distance of 

 time. A foot-path runs by the side and below it, but there is no 

 hedge or other material limit to check the wash of the soil down- 

 wards, other than the slight ridge of grass that grows on the out- 

 ward edge of the lowest furrow by the side of the path, which 

 latter remains uncovered and undisturbed. It is evident that 

 the slightest impediment would suffice to check the descent of the 

 silt into the path and cause it to settle above. 



This I have no hesitation in asserting to be the simple explana- 

 tion of the origin of those "thousands of raised sea-beaches from a 

 few inches to several feet in height which may be found in Wilt- 

 shire, Dorset, and other counties," according to Mr. D. Mackintosh. 



Were they ever sea or indeed river-beaches, they would be found 

 composed of shingle or rolled pebbles. If sea or river- worn cliffs. 



1 



