It is obvious that formal centuriation in straight lines and rectangular divisions, by the _Agrimensores_, produced something entirely different from the open field system as we have found it in England. But Siculus Flaccus records that in some cases, when vacant districts were occupied by settlers without this formal centuriation, as '_agri occupatorii_'--the settlers taking such tracts of land as they had the means or expectation of cultivating--the boundaries were irregular, and followed no rules but those of common sense and the custom of the country.[395] And he gives as an instance of such a common-sense rule the custom about '_supercilia_,' or _linches_, the sloping surface of which, where they formed boundaries between the land of two owners, should be kept the same number of feet in width, the slope always belonging to the upper owner, because otherwise it would be in the power of the lower owner, by ploughing into the slope, to jeopardise the upper owner's land.[396] This, he says, is the reason of the rule that the land of the owner of the upper terrace generally descends to the bottom of the slope.[397] «The holdings sometimes composed of scattered pieces.» Here, in this mention of _linches_ and irregular boundaries, traces seem to turn up of an open-field husbandry; and a few pages further on the same writer makes another observation which shows clearly that frequently the holding, like the yard-land, was [p278] composed of _scattered pieces_ in open fields, and that this scattered ownership, as in England, was the result of an original joint occupation, and probably of a system of co-operative ploughing. He says[398] that in many districts were to be found _possessores_ whose lands were not contiguous, but made up of little pieces scattered in different places, and intermixed with those of the others, the several owners having common rights of way over one another's land to their scattered pieces, and also to the common woods, in which the _vicini_ only have common rights of cutting timber and feeding stock. This reference to the common woods and rights of way belonging only to the 'vicini' seems to show that the scattering of the pieces in the holdings had arisen as in the later open-field system, from an original co-operation of ploughing or other cultivation. «The result of joint occupation.»