Those who wish to make themselves thoroughly acquainted with the different circumstances of these discoveries, and with the various forms of rough implements brought to light, will have to consult the original memoirs[1022] which have been written concerning them. Both in cists or graves, and in the remains of ancient circular habitations, have numerous hammer-stones and pestles been found, associated with various other articles manufactured from stone and bone. Some of these are extremely rude, and appear hardly deserving of the names of spear-heads, knives, chisels, battle-axes, &c., which have been bestowed upon them. There can, however, be no doubt of their being of human manufacture, whatever purpose they may have served. A few well-formed and polished stone celts were found in company with the objects of this class in the “Underground House of Skaill,” Orkney, which, however, was not, strictly speaking, subterranean. In the building, and in the midden around it, were very great numbers of oval sandstone pounding-stones and of large sandstone flakes, probably knives of a rude kind, a pebble with a groove round it like a ship’s block, and a few celts. In Shetland these rude stone implements have been found with human skeletons interred in cists, sometimes with polished weapons.[1023] A very curious implement, somewhat T-shaped, with pointed extremities, and grooves round the transverse part, was found in the broch of Quoyness,[1024] Sanday, Orkney, and has been figured. Many of the pestle-like stones are merely chipped into a somewhat cylindrical form, but others have been picked or ground all over, so as to give them a circular or oval section. The ends in many instances are more or less splintered, as if by hammering some hard substance rather than by pounding, and the exact purpose to which they were applied it is extremely difficult to divine. Four of them are shown, on a small scale, in Figs. 174 to 177. [Illustration: Fig. 174.—Shetland. 20 1∕2 in.] [Illustration: Fig. 175.—Shetland. 19 in.] [Illustration: Fig. 176.—Shetland.] [Illustration: Fig. 177.—Shetland.] [Illustration: Fig. 178.—Shetland. 21 in.]