We may perhaps hope to find other clues to the religious ideas of the Bronze Age in megalithic monuments and in the engraved stones which have been already mentioned.[867] There are certain designs upon the latter of which the meaning is evident. The figure of an axe graven on a cist at Kilmartin in Argyllshire has many analogues on dolmens in the Morbihan and on the walls of artificial sepulchral grottoes in the department of the Marne; and, as the axe in the Mycenaean Age was a symbol of Zeus, we may suppose that such engravings represented a widespread cult of one of the most fruitful of human inventions, which originated in neolithic times, and survived in the manufacture of miniature celts to serve as pendants and, still later, in the use of stone celts as amulets.[868] The most common devices, however, are small circular depressions, called cup-markings, and concentric circles; while occasionally groups of concentric circles are united by grooves. Cup and ring markings are found on the stones of cists, on standing stones, on boulders, and on rocks in most parts of Scotland, in Carnarvonshire and Merionethshire, in Northumberland, Cumberland, Westmorland, Lancashire, Yorkshire, Man, Derbyshire, Staffordshire, Dorsetshire, and Cornwall, and likewise in Ireland, France, Germany, Switzerland, Portugal, Scandinavia, Asia, Africa, and America.[869] Natural cup-markings have been noticed on the covering-stones of certain dolmens;[870] and it may be that such stones were deemed lucky and that, when they could not be obtained, they were imitated; but of those which are artificial the significance remains unknown.[871] The rings may perhaps in some instances be symbolical of sun-worship, for on the cairn of Lough Crew in Ireland and in Scandinavia a few have rays;[872] and since we find them on the covering-stones of cists, while in Australia similar designs, drawn on rocks, are magical or sacred,[873] it would seem probable that they had some religious meaning.[874] Sun-worship undoubtedly prevailed in certain parts of the British Isles. A few years ago there was found in Zeeland a gold-plated bronze disk, engraved with concentric circles and mounted on a miniature car with the model of a horse attached, which was recognized by all archaeologists as a votive object, connected with the worship of the sun. Similar disks, two of which are ornamented with a cruciform pattern--a well-known solar symbol--have been exhumed in Ireland, and a fragment of one in a barrow near Bath.[875] Besides the spirals which have been already mentioned, the most remarkable of all the rock-carvings is a swastika on a rock near Ilkley, identical with one which has been discovered in Sweden, not far north of Gothenburg: the oldest known examples of this mystical figure come from the second city that was built upon the site of Troy.[876]