. S. F. C. 1897. (To face page 426.) 
Plate XVI 
k 
w 0 
^0 
1 
: 2 
A- 
s, 
6 
ijV- 
'j 
7 
8 
0 
tb 
c 
H 
It 
ti 
14 
1 5 
Group A. 
% 
3 
% | % 
lo li l2 - 
t % I 
14 IS >6 1 / 
TWISTED, ELONGATED, AND OTHERWISE IRREGULAR PEARLS. 
Those in Group B often very brilliant and highly colored ; those in Group A white or paler. In Group A, fig. 6 almost triangular, and 
somewhat so in fig 13, with a sharp ridge above. Angular forms like these would suggest pebbles as nuclei. 
