Mr Green alluded to the Danish 'byes' as found, by exception, 'about Wirral in Cheshire',[160] and held that Norsemen from the Isle of Man had founded 'the little group of northern villages which we find in the Cheshire peninsula of the Wirral'.[161] I cannot find them myself. In his 'Notes on the Domesday Survey, so far as it relates to the Hundred of Wirral'[162] (1893), Mr Fergusson Irvine, in a paper which shows, though somewhat discursive, how much can only be done by intelligent local research, has collated all the Domesday entries. 'Raby' is the one place I can there find in the peninsula with the 'bye' termination; while out of fifty-one entries twenty refer to places with the English termination 'tone', and the Anglo-Saxon test-words 'ham' and 'ford' are found in four others. There were, doubtless, Norse elements in the peninsula, but they were not strong enough to change the place-names or divide the land on their own system. In the same way, Chester had its 'lawmen', though it was not one of the Five Boroughs, nor is what I have termed the Scandinavian formula applied to Cheshire in Domesday. So, too, there were lawmen at Cambridge, and their heriot included eight pounds,[163] which occur in the above formula as the twelve marcs of the Danish 'Hundred'. Yet the whole system of Cambridgeshire was non-Danish. It was only, in short, where the northern invaders had settled down as a people that they were strong enough to divide the land anew and organize the whole assessment on their own system. X. THE YORKSHIRE UNIT We have seen that the unit of assessment for the carucated districts of England was 'vi. carucatæ terræ', just as five hides was the old unit in the south. We have also seen that the former reckoning extended over those districts which the Danish immigrants had settled. There remains the question whether the Danes had merely substituted six for five in the pre-existing arrangement, or had made a wholly new one for themselves based on actual area. It is _primâ facie_ not probable that they can have adopted the latter course, for the uniformity of their assessment proves its artificial character. Yet, in his remarkable paper on 'The Ploughland and the Plough',[164] Canon Taylor has arrived at the conclusion that: The geldable carucate of Domesday does not signify what the carucate usually signifies in other early documents. The 'carucata ad geldum' is not as commonly stated by Domesday commentators, the quantity of land ploughed in each year by one plough, but it is the quantity tilled in one year _in one arable field_ by one plough.[165]