SURNAME DISTRIBUTION IN FRANCE - A DISTANCE ANALYSIS BY A DISTORTED GEOGRAPHICAL MAP

The distribution of surnames in 90 distinct regions in France during t wo successive periods, 1889-1915 and 1916-1940, is analysed from the c ivil birth registers of the 36,500 administrative units in France. A n ew approach, called 'Mobile Site Method' (MSM), is developed to allow representation of a surname distance matrix by a distorted geographica l map. A surname distance matrix between the various regions in France is first calculated, then a distorted geographical map called the 'su rname similarity map' is built up from the surname distances between r egions. To interpret this map we draw (a) successive map contours obta ined during the step-by-step distortion process, revealing zones of hi gh surname dissimilarity, and (b) maps in grey levels representing the displacement magnitude, and allowing the segmentation of the geograph ical and surname maps into 'homogeneous surname zones'. By integrating geography and surname information in the same analysis, and by compar ing results obtained for the two successive periods, the MSM approach produces convenient maps showing: (a) 'regionalism' of some peripheral populations such as Pays Basque, Alsace, Corsica and Brittany; (b) th e presence of preferential axes of communications (Rhodanian corridor, Garonne valley); (c) barriers such as the Central Massif, Vosges; (d) the weak modifications of the distorted maps associated with the two periods studied suggest an extension (but limited) of the tendency of surname uniformity in France. These results are interpreted, in the ni neteenth- and twentieth century context, as the consequences of a slow process of local migrations occurring over a long period of time.