Long pieces for sheathing and for the gunwale members were split from white cedar or black spruce. The splitting of such long pieces as these required not only proper selection of clear wood, but also careful manipulation of wood and tools in the operation. Splitting of this kind--say, for ribs in the finish cut--was usually done by first splitting out a batten large enough to form two members. To split it again, a stone knife was tapped into the end grain to start the split at the desired point, which, as has been noted, was always at the upper end of the stick, not at the root end. Once the split was opened, it was continued by use of a sharp-pointed stick and the stone knife; if the split showed a tendency to run off the grain as it opened, it could be controlled by bending the batten, or one of the halves, away from the direction the split was taking. The first rough split usually served to show the worker the splitting characteristics of a piece of wood. This method of finishing frame members in bark canoes accounts for the uneven surfaces that often mark some parts, a wavy grain producing a wave in the surface of the wood when it was finished. If it were desired to produce a partially split piece of wood, such as some tribal groups used for the stems, or in order to allow greater curvature at the ends of the gunwale, the splitting was stopped at the desired point and a tight lashing of rawhide or bark was placed there to form a stop. The tapering of frames, gunwales, and thwarts and the shaping of paddles were accomplished by splitting away surplus wood along the thin edges and by abrasion and scraping on all edges. Stone scrapers were widely employed; shell could be employed in some areas. Rubbing with an abrasive such as soft sandstone was used when the wood became thoroughly dry; hardwood could often be polished by rubbing it with a large piece of wood, or by use of fine sand held in a rawhide pad. By these means the sharp edges could be rounded off and the final shaping accomplished. Some stone knives could be used to cut wood slowly, saw fashion, and this process appears to to have been used to form the thwart ends that in many canoes were tenoned into the gunwales. A stone knife used saw fashion would also cut a bent sapling easily, though slowly. To cut and trim bark a stone knife was employed; to peel bark from a tree, a hatchet, axe, or chisel could be used. [Illustration: Figure 11 Stone scraper]