Another form of sink-stone, weight, or plummet, was formed by boring a hole towards one end of a flattish stone. Such a one, weighing 14 1∕4 oz., was dredged from the Thames at Battersea.[890] Another, of oval form, pierced at one end, from Tyrie,[891] Aberdeenshire, is in the National Museum at Edinburgh; and a wedge-shaped perforated stone from Culter, Lanarkshire,[892] was probably intended for the same purpose. These may have been in use for stretching the warp in the loom when weaving. They are found of this form with Roman remains.[893] |238| CHAPTER X. HAMMER-STONES, ETC. Under this head I propose to treat of those implements which have apparently been used as hammers, but which, for that purpose, were probably held in the hand alone, and not provided with a shaft, as the groove or shaft-hole characteristic of the class last described, is absent. At the same time there are some hammer-stones in which there are cavities worked on either face, so deep and so identical in character with those which, in meeting each other, produce the bell-mouthed perforations commonly present in the hammers intended for hafting, that at first sight it seems difficult to say whether they are finished implements, or whether they would have become perforated hammer-heads had the process of manufacture been completed. Certainly in some cases the cavities appear to be needlessly deep and conical for the mere purpose of receiving the finger and thumb, so as to prevent the stone slipping out of the hand; and yet such apparently unfinished instruments occur in different countries, in sufficient numbers to raise a presumption that the form is intentional and complete. There are some instances where, as was thought to be the case with a quartz pebble from Firth,[894] in Orkney, the unfinished implements may have been cast aside owing to the stone having cracked, or to the holes bored on each face not being quite opposite to each other, so as to form a proper shaft-hole.