114 
ARCHAEOLOGY: N. C. NELSON 
With these values of a„, jSn, t« we proceed to compute the successive converg- 
ent sets and the corresponding determinants. The following is a convenient 
arrangement of the work: 
Bn 
c„ 
1 
0 
0 
0 
rv 
U 
1 
0 
0 
u 
0 
1 
0 
o 
9n 
7« 
u 
0 
0 
1 
1 
2 
— 4 
1 
1 
2 
— 4 
0 
1 
1 
1 
2 
2 
-3 
0 
0 
1 
1 
2 
3 
-3 
0 
0 
1 
1 
2 
3 
-2 
0 
0 
0 
1 
1 
2 
-4 
0 
1 
1 
3 
5 
7 
-9 
0 
0 
4 
13 
22 
31 
-39 
0 
0 
0 
1 
2 
3 
-2 
0 
0 
0 
1 
1 
2 
-4 
2 
2 
2 
33 
55 
79 
-99 
The last determinant yields us the solution of the proposed problem. Com- 
puting the minors we easily get the following general values for the unknowns 
in the equation: 
X = - 29r - 57s + 54/ - 65u 
y = 3r-i-4s - 4:t-{-7u 
2 = 5r + ll5 - 11/+ llw 
w = — 4r — 85 + 7t— 9u 
THE ARCHAEOLOGY OF THE SOUTHWEST: A PRELIMINARY 
REPORT 
By N. C. Nelson 
American Museum of Natural History, New York 
Communicated by Henry F. Osborn, February 6, 1919 
Introductory. — Since my last communication to the Proceedings of the 
National Academy (Vol. 3, pp. 192-195) two years ago, concerning the time 
distribution of aboriginal traits in the Mammoth Cave region of Kentucky, it 
has become possible to report upon the stratigraphic conditions in two addi- 
tional North American culture centers. One of these new centers, viz., the 
Florida-Georgia characterization area, directly adjoins that in which the Mam- 
moth Cave occurs, in fact is in a large sense one with it and need not therefore 
be specifically discussed. The other center, of special concern here is sepa- 
