Salmon, in his _History of Hertfordshire_, imagines that the East
Saxon and Mercian kingdoms were, in the upper part of this county,
separated from each other by the Ermin-street; and in the lower part,
in the parish of Cheshunt, by a bank, which anciently reached from
Middlesex through Theobald's Park, across Goffe's Lane, to
Thunderfield Grove, over Beaumont Green, to Nineacres Wood. There is a
custom in the manor of Cheshunt, he says, "by which the elder brother
inherits above the bank, and the youngest below it, in the same
fields;--which could not have been introduced but from the different
laws of a different government."