From:
http://www.publicatio...gmt/jd990429/alan.htm
There are certain presumptions which assist the inferences which may be drawn from the topographical features. Perhaps the best known is the one which is drawn from the existence along the boundary of a hedge and a ditch. In such a case, it is presumed that the boundary lies along the edge of the ditch on the far side from the hedge. The basis of this presumption was explained by Lawrence J. in Vowles v. Miller (1810) 3 Taunt. 137, 138:
"The rule about ditching is this: No man, making a ditch, can cut into his neighbour's soil, but usually he cuts it to the very extremity of his own land: he is of course bound to throw the soil which he digs out, upon his own land; and often, if he likes it, he plants a hedge on top of it . . . ."