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72 The basal margin is defined as the most proximal edge, rela- tive to the aboriginal user, that lies perpendicular to the long axis. Basal margin configurations include: flat, having no cur- vature; concave, curving inwards toward the proximal end, yet having a gradual curvature and constant radius; convex, curving away from the proximal end; and indented, having a more radical depression ap- proaching a "V" shape, rather than curving inwards. Stem is used to describe that portion of the projectile which lies below the blade, and which terminates in the basal margin. The upper terminus of the stem, where present, is at the upper margin of any lateral indentation, which also defines part of the tang at its innermost intrusion toward the long axis. The stem, then, runs from the most medial point of any notch that interrupts the blade, and ter- minates where it intersects the basal margin. Stems are either paral- lel-sided expanding, that is, widening toward the basal margin, or contracting, narrowing toward the basal margin. The tang is produced when the blade edge is indented or constric- ted, and is defined as the intersection of the blade margin and the upper margin of the indentation. The type of tang is determined by the angle of the upper margin of the indentation relative to the long ~ axis measured from the tip towards the basal margin, and by the degree of roundness or sharpness present. A lateral tang has an upper notch margin that is perpendicular to the long axis. Oblique tangs are angled toward the base, and thus subtend an angle greater than 90°. It would be possible to have an acute tang, with an angle of less than 90°, but no such projectiles were recovered. If the intersection of the ~ blade margin and upper notch margin is fairly definite, it is consider- ed to be a sharp lateral or oblique tang. If the intersection is curved, or has a discernable radius, it is considered to be a rounded tang. Blade forms of projectiles in the collection are limited to either triangular or biconvex outlines. The difference between the two forms depends upon whether or not the edge, from the tip to the tang, is straight or curves outward from the long axis. The biconvex form has an excurvate edge rather than straight. No concave blade forms, such as discussed by Irwin-Williams and Irwin (1906) were recovered. In the following classification, every attempt has been made to a- void excessive division, but the range of materials under consideration, coupled with the limited sample make it necessary at times to develop ~ classes with only a few members. Projective points: non-stermned, concave base. Fig. 7a, b. Description: Biconvex outline, basal thinning and grinding. The widest point, on the blade is in the lower third; basal concavity extends the full - width of base, and is shallow in depth. Materials: chert and quartzite. Size range: length, 39 mm., complete specimen only; width, 21 mm.; and thickness, 7 mm. - Special notes: the com~~lete quartzite specimen has bifacial basal thin- . Wing and flal.e scars oriented parallel to the long axis. Grinding is present on both edges of the blade.