No other county in England is so prolific in prehistoric circles as that of Derby. Many, probably, are still undiscovered, for the writer has been able to add several to the list. Yet at least twenty can be visited with the assistance of an Ordnance map, another dozen have disappeared in modern times, but are recorded by old authorities, and, no doubt, as many more lie hidden by the heather on our little-frequented moors. All are in the north-west quarter of the county, within a space of less than twenty miles square, and at an altitude of not less than a thousand feet. Although differing much in dimensions and details, there was a common purpose, and consequently there is a uniform character in all. Commencing with the smallest, and measuring the diameters from stone to stone, we find: (1) a plain circle of standing stones, ten feet across, and with either a single stone or heap of stones at a short distance outside the circle, which, for convenience of reference, may be called the “pointer”; (2) similar, but with a diameter of twenty feet, and an encircling mound, or vallum, of earth, in the inner edge of which the stones are usually set; (3) the same, but with diameters of thirty, forty, sixty, eighty, one hundred, and one hundred and fifty feet. It is probable that, originally, all had a cromlech of some description in the centre, or, as at Ford, a small circle in the north-eastern quarter. At Park Gate this remains as a central cone of stones; at Arbor Low as three great stones, which, with the rest, have fallen; on Offerton Moor it was four stones, and at the Wet Withens a single stone. Outside the circle at Arbor Low is a raised causeway of earth extending in a curved line from the circle towards its artificial mound, Gib Hill, a thousand feet away, which once it probably joined. At Stadon a similar causeway leaves the circle, but returns to it again in the form of the lower half of a triangle, and at the Wet-Withens Mr. Trustram called attention to the remains of what was, very possibly, an avenue of stones arranged in parallel lines at equal distances towards the south-west. These alignments must be considered with reference to the avenue at Stonehenge. The circles are never present on the actual summit of a hill, but are almost invariably on the hillside near the highest point. Hence on one side they have a sharp and near horizon and on the other a distant view. All have, or presumably have had, a “pointer” outside the circle; that is, an artificial mound of earth or stones or a smaller circle to the larger examples, and a single upright stone to the smaller.