8 
PACIFIC SCIENCE, Vol. XIX, January 196-5 
cone is relatively coarse. It is composed of rather 
large masses of spatter as well as angular blocks 
which are probably parts of the shattered solid 
top of the feeding aa flows. Many of these 
masses of spatter are 5-6 inches in diameter 
and 2 inches thick and are crudely disk-shaped. 
They occur in a matrix of finer cinders and glass 
sand. Higher in the cone the material is con- 
siderably finer grained and is composed pre- 
dominantly of glass sand averaging less than a 
few millimeters in size. 
The glass sand or ash from all three of the 
historic littoral cones appears very similar under 
the microscope. It is composed principally of 
angular fragments of fresh, light brown, trans- 
parent glass containing abundant crystallites. In 
addition, 10 to 20 percent of the ash is composed 
of fragments, of basalt and black, opaque glass. 
Small vesicles are common in both the trans- 
parent and opaque glass. They occupy 15 to 20 
volume percent of the fragments and are gen- 
erally 0.2 to 0.3 mm in diameter. 
CHEMISTRY 
Chemical analyses have been made of the 
glassy ash of each of the three historic littoral 
cones as well as of the lava flows which fed the 
cones ( Table 1 ) . Ash samples were collected 2 
ft below the surface on the upper slopes of the 
littoral cones. Lava samples were collected from 
TABLE 1 
Chemical Analyses of Historic Littoral Cone Ash and Associated Lava Flows, Hawaii 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
sio 2 
48.86 
48.43 
— .43 
51.03 
50.58 
— .45 
51.89 
51.83 
— .06 
— .31 
Ahos 
11.46 
10.70 
— .76 
13.20 
12.63 
— .57 
13.90 
13.95 
+ -05 
— .43 
Fe 2 Os 
2.13 
1.15 
— .98 
3.26 
1.65 
— 1.61 
3.24 
1.75 
— 1.49 
— 1.36 
FeO 
9.09 
10.08 . 
+ .99 
8.04 
9.35 
+ 1.31 
7.88 
9.17 
+ 1.29 
+ 1.20 
MgO 
14.13 
16.29 
+ 2.16 
9.40 
11.08 
+ 1.68 
7.21 
7.05 
— .16 
+ 1.23 
CaO 
9.27 
8.67 
— .60 
10.02 
9.44 
— .58 
10.61 
10.58 
— .03 
— .40 
NasO 
1.84 
1.71 
— .13 
2.22 
2.01 
— .21 
2.25 
2.31 
+ .06 
— .09 
KoO 
.36 
.35 
— .01 
.42 
.38 
— .04 
.36 
.35 
— .01 
— .02 
h 2 o+ 
.23 
.22 
— .01 
.11 
.33 
+ .22 
.06 
.14 
+ .08 
+ .10 
h 2 o— 
.01 
.00 
— .01 
.01 
.13 
+ .12 
.01 
.01 
.00 
+ .04 
TiCC 
2.14 
2.00 
— .14 
2.13 
1.94 
— .19 
2.10 
2.11 
+ .01 
— .11 
p 2 o 5 
.19 
.18 
— .01 
.24 
.21 
— .03 
.22 
.22 
.00 
— .01 
MnO 
.17 
.17 
.00 
.17 
.17 
.00 
.18 
.17 
— .01 
.00 
co 2 
.01 
.00 
— .01 
.01 
.01 
.00 
— .01 
Cl 
.04 
.02 
— .02 
.02 
.01 
.02 
+ .01 
F 
.03 
.02 
— .01 
.03 
.03 
.02 
— .01 
Total 
99.96 
99.99 
+ .03 
100.25 
99.96 
— .35 
99.96 
99.68 
— .28 
— .16 
1. Olivine basalt from 1840 flow between 1840 littoral cone remnants at Sand Hill, Puna, Hawaii. D. F. 
Powers, U.S. Geological Survey, analyst. 
2. Glassy basaltic sand 80 ft below summitt of southern 1840 littoral cone remnant, Puna, Hawaii. D. F. 
Powers, U.S. Geological Survey, analyst. 
3. Difference between 1 and 2. 
4. Hypersthene basalt, lava of 1868, road near east edge of flow in Kahuku Ranch, Hawaii. J. H. Scoon, 
Univ. of Cambridge, analyst. Tilley and Scoon, 1961. 
5. Glassy basalt sand, 100 ft below summit, Puu Hou (1868) littoral cone, Kau, Hawaii. D. F. Powers, U.S. 
Geological Survey, analyst. 
6. Difference between 4 and 5. 
7. Basalt from 1919 Alika flow 50 yards east of Alika littoral cone, Kona, Hawaii. D. F. Powers, U.S. Geo- 
logical Survey, analyst. 
8. Glassy basaltic sand from Alika (1919) littoral cone, Kona, Hawaii. D. F. Powers, U.S. Geological Sur- 
vey, analyst. 
9. Difference between 7 and 8. 
10. Average of 3, 6, and 9- 
