From the contents of the tumuli we are able partially to apply to them a relative system of chronology, the accuracy of which appears to be satisfactorily borne out. No archæologist has yet done for any district of Scotland what the intelligent research of Sir Richard Colt Hoare effected for Wiltshire. No other single district, indeed, offers the same tempting field for the study, and few archæologists possess his ample means for carrying out such investigations. He has adopted a subdivision, which distinguishes fourteen different kinds of barrows, classified according to their shape, and furnishes a systematic nomenclature, which is of general avail. Observations since carried out over a more extensive field enable us in some degree to modify this system, and reduce the number of true barrows, while even of these some are probably only the result of accident, or of the caprice of individual taste. The following are the best defined among the varieties noted by Sir R. C. Hoare:--1. The long barrow, resembling a gigantic grave; 2. The bowl barrow, from its similarity to an inverted bowl; 3. The bell barrow; 4. The twin barrow, consisting of two adjacent tumuli, one of them generally larger than the other, and both inclosed in one fosse or vallum; 5. The Druid barrow, generally a broad and low tumulus, surrounded by a vallum. The last name was given on insufficient evidence by Dr. Stukely, Sir R. C. Hoare's predecessor in investigating the antiquities of Wiltshire. The latter has subdivided the class into three varieties, and there seems some reason to think that such indicate the place of interment of females; but more extensive observation is required to establish so interesting an inference. The remaining distinctions appear to be either accidental, or referring to earth-works, certainly not sepulchral. Among this last are the "pond barrows," hereafter referred to as the remains of primitive dwellings, and the conical mounds or moat-hills, of which Silbury Hill is probably the largest in the world, designed as the lofty tribunal where the arch-priest or chief administered, and frequently executed, the rude common law of the northern races. The laborious excavations carried out under the direction of the Archæological Institute during the Salisbury Congress in 1849, have at least put an end to any ideas of Silbury Hill being a sepulchral mound.