Sentence:  Within ten years <WSD>linches</WSD> were formed; rain washed down the mould, some accident arrested it at a certain line, and a terrace was the result. Certainly the tendency is for the upper part of such a field to be denuded of mould, to be worked "to the bone," i.e. to the bare chalk or stone. But the first makers of <WSD>linches</WSD> had no choice. They had to farm on slopes or not at all, ... 
Meaning of the word marked with <WSD> tags:  A ledge, a terrace; a right-angled projection; a lynchet.