The most remarkable instance which can be quoted about these crosses, and at the same time the easiest to notice, is that presented by England, where two races live side by side, mixed together, without one having absorbed the other since the time of Strabo, Tacitus, and Julius Cæsar. England, isolated from Europe, ought necessarily to be a fertile field for the anthropologist, and it will be there where the history of historic and pre-historic races will soonest be made. Eminent men work at it with ardour; and the certainty of remounting, through archæology and palæontology, to the first races which invaded England, at a time when the use of metals was unknown in the west, makes this study one of the most interesting of the present day. Two distinct races divide Great Britain, or, at least, representatives of two races are found there; and in the midst of an immense number of intermediate individualities, the least accustomed eye will not fail to distinguish these two fundamental types, as different as two men with white skins can be. One of these races is composed of tall, strong, powerful men, with transparent skin, and blue eyes;[265] the other, with a more tawny complexion, has black, curling hair.[266] The first were formerly called Caledonians, the second Silurians, very like the Iberians of the Spanish peninsula: the first, of Germanic, or northern origin; the second, of Celtic, or southern origin. Nobody denies, at the present day, that these two races are well characterised, and every day one can meet perfect specimens of them in England. We may quote certain districts where the Silurian, Iberian, or Celtic race, as tradition wills it, are dominant;[267] for example, in the north-west of Glamorganshire, in the outskirts of Merthyr, and in the Vale of Neath.[268] Mr. John Philips finds them equally abundant in the Danelag[269] district, between Leicester, Nottingham, and Derby, with the same characteristics, “black eyes and hair, uniform, or rather, dark complexion.”[270] Among these two races there are of necessity a considerable number of cross-breeds who, allying themselves among one another, or to the pure types, produce varied results, and in this manner unite the two groups by a multitude of inappreciable shades of difference.