292 Onsymmetric Arrow-Heads and Allied Forms. [May, 
= Page 28, he under-estimates the amount of thickness of rocks 
with which he has to deal if he employ the “ usual manner” of 
calculating it, for Rogers’ and Frazer’s sections of the New Red 
in Pennsylvania make the total thickness 51,000 feet. 
It is interesting in Note B to find Mr. Russell also testifying to 
the probable high and swampy character of the southern end of 
the Triassic estuaries, 
Taking the papers PRAE A we cannot fail to recognize that 
they form a very valuable and suggestive arsenal from which to 
draw weapons to renew the old attack on the New Red. 
:0; 
ON UNSYMMETRIC ARROW-HEADS AND. ALLIED 
MS. 
BY S. S. HALDEMAN. 
LTHOUGH most stone arrow-heads have a symmetric out- 
line, a large collection will generally present variations which 
may be due to unsuitable material, to want of skill in the work- 
man, to a love of variety, to intentional adaptation to a purpose, 
or to the consideration that a single barb might be sufficient. 
Love of ornament appears in the use of paint, and in the selec- 
tion of finely colored jasper and chalcedony for implements. 
While irregularities would interfere with the function of arrows, 
all these objects are not to be regarded as arrow-heads, some of 
the larger kinds being for spears, while others are probably 
borers (Fig. 4), scrapers (Fig. 10) and knives (Fig. 8). As in 
civilized life, the workman whose kit is limited must make one 
implement serve the purposes of several. In fact, the enterprising 
explorer, Major J. W. Powell, brought from the Rio Virgen small 
knives of what would be regarded as arrow-heads if found 
detached, but which were fastened (with the gum of Larrea mexi- 
cana) in a notch in the end of a round wooden handle (see Fig. 
I, p. 2, in Rau’s Archzol. Collections of the National Museum). 
The want of symmetry may be in the form of the body (Figs. 
I, 3, 4, 8), in the shape and inequality of the barbs (Figs. 7, 11), 
and in the slight indication, or the absence of one of the barbs 
(Figs. 2, 5, 6, 8, 9). 
A barb may be accidentally broken off during or after making, 
1 I have an arrow-head from Tennessee, one side of which is painted with a fer- ` 
ruginous mie olor. 
