50 
PACIFIC SCIENCE, Vol. XXII, January 1968 
TABLE 1 ( Continued ) 
INCIDENCE OF OCCURRENCE 1 
ROSS 
ARRIVAL 
CAPE 
ROBERT- 
SABRINA 
SPECIFIC NAME 
BARRIER 
BAY 
HALLETT 
SON BAY 
COAST 
Spongod/scus sp. 
A 
O 
O 
A 
C 
S. favus Ehrenberg 
O 
O 
O 
A 
A 
S. radiatus Haeckel 
O 
O 
O 
A 
A 
Stylotrochus craticulatus Haeckel 
C 
O 
O 
R 
0 
Stylotrochus sp. 
c 
O 
O 
R 
C 
Spongotrochus sp. 
0 
O 
O 
C 
C 
Dicolocapsa microcephala Haeckel 
0 
O 
O 
C 
C 
Tristylospyris sp. 
0 
O 
O 
R 
O 
Dictyocephalus sp. A 
0 
O 
O 
R 
O 
Dictyocephalus sp. B 
0 
O 
O 
R 
O 
1 Explanation of symbols: 
A = Abundant (more than 1 specimen per cm 2 ) 
C — Common (more than 0.1 and less than 1.0 per cm 2 ) 
R = Rare (less than 0.1 per cm 2 ) 
O = None 
Barrier, Robertson Bay, and Sabrina Coast en- 
vironments are ones of unstable sea ice condi- 
tions, it seems significant that silicaceous or 
arenaceous skeletal remains are dominant among 
organic material in the sediments. And it ap- 
pears equally significant that calcareous shells 
are dominant in the sediments of Arrival Bay 
and Cape Hallett — where the sea ice cover is 
stable and smooth. 
McKnight (1962) said, ". . . the calcareous 
benthonic populations (of foraminifera) are 
believed to be in areas of little or no bottom 
current, and the arenaceous populations to be 
in areas of either greater depths or bottom 
currents.” McKnight attributed the high per- 
centage of calcareous benthonic foraminifera to 
a lack of deposition of ice-rafted elastics, giving 
an apparent increase in production. 
The evidence seems to support McKnight’ s 
postulation of ice-rafting, since feldspar domi- 
nates the sediments where sea ice is unstable. 
Tressler (1957) measured the thickness of un- 
stable hummocky pack ice in the western Ross 
Sea in late October. He found that most of 
the ice scarcely exceeded 3-4 ft in thickness. 
It is indeed possible for an iceberg to plow 
through this kind of ice and to enter embay- 
ments such as Robertson Bay. But an iceberg 
cannot penetrate stable bay ice that is thick, to 
encroach upon an embayment. 
In concurrence with McKnight’s belief 
(1962) the evidence shows that calcareous 
shells are dominant in embayments where the 
ice-cover is stable and bottom currents are 
weak. This might well result in an "isolated” 
benthonic environment where the amount of 
bound carbonate enhances the production of 
calcareous shells. Since radiolaria are plank- 
tonic, it is unlikely that their skeletal remains 
will be found in embayments which are isolated 
from the body of the current. 
CONCLUSION 
From the foregoing it appears that knowl- 
edge of the amount of calcareous remains in 
the sediments of an unobserved Antarctic loca- 
tion would be of value in determining the suit- 
ability of the ice-cover for aircraft and staging 
operations. Moreover, such information is likely 
to be of even greater value to submarine stratig- 
raphy and its application to paleo-oceanography. 
REFERENCES 
Hollin, J. T., and R. L. Cameron. 1961. 
igy glaciological work at Wilkes Station, 
Antarctica. J. Glaciol. 3:833-842. 
McKnight, W. M., Jr. 1962. The Distribu- 
tion of Foraminifera off Parts of the Ant- 
arctic Coast. Unpublished thesis (degree not 
stated), Florida State Univ. vii — |— 118 pp. 
Priestley, R. E. 1923. Physiography, Robert- 
son Bay and Terra Nova Bay. British (Terra 
Nova) Expedition. Harrison & Sons, Ltd., 
London. Pp. 1-84. 
