The type of penannular arm ring, which is of rounded or quadrangular section, with tapering or slightly flattened ends, of which so many examples were associated with the twisted rings and bulbous brooches in the Skaill hoard, has not occurred in any other metal than silver. Like the other types associated with them, they have not been found in Scotland beyond the area of the Scandinavian colonisation. Within that area, however, they appear not unfrequently. Wallace records the discovery of a hoard of nine in one of the mounds at Stennis, in Orkney. Another hoard, of which the precise number is not given, was found in 1774 at Caldale, near Kirkwall, with a horn containing 300 silver pennies of Canute the Great. In 1830 six or seven were found at Quendale, in Shetland, with a horn full of Anglo-Saxon coins of Ethelred, Ethelstan, Edwy, and Edgar. In 1850 a hoard of at least six were found in the island of Skye, but in circumstances of which there is no record. [Illustration: Fig. 91.—Penannular Arm-ring of Silver, one of a hoard of eight, found at Burn of Rattar, Caithness (3½ inches diameter).] In 1872 a hoard of eight were found in a cist of stones in or close to an ancient burying-ground near where the burn of Rattar enters the Pentland Firth, in Caithness. One of these is shown in Fig. 91. All these are similar in form to each other, and to the rings of the same type found in Scandinavia in association with the other types of silver ornaments previously described. They are more frequently plain than ornamented, and when ornamented their decoration consists simply of a series of impressions formed by a triangular punch, with one, two, or three dots in the field. This species of ornamentation is only found on these silver ornaments in Scotland, but in Scandinavia it is common to them and to the oval bowl-shaped brooches of brass which were the characteristic personal ornaments of the closing period of the Scandinavian Paganism. It follows from this enumeration of the characteristics of form and ornament exhibited by the different varieties of these silver ornaments which have been deposited in hoards within the area of the Scandinavian colonisation of Scotland, that they possess a character which is distinctive and peculiar, being neither wholly Celtic nor wholly Scandinavian, but owing its individuality to an intermixture of characteristics derived from forms and systems of ornament which are peculiar to each of these racial areas.