472 PETROLOGICAL ABSTRACTS AND REVIEWS 
WASHINGTON, HENRY S. “Contributions to Sardinian Petrog- 
raphy. I. The Rocks of Monte Ferru,” Amer. Jour. Sci., 
XXXIX (1915), 513-20, figs. 2, analyses. 
In this paper are described trachyte, trachytic phonolite, basalt, 
and analcite-basalt from Monte Ferru, Sardinia. 
WASHINGTON, HENRY S. ‘The Calculation of Calcium Orthosili- 
cate in the Norm of Igneous Rocks,” Jour. Wash. Acad. Sci., 
V (1915), 345-50. 
Calcium silicate, which was originally calculated in the C.I.P.W. 
system as 4CaO.3Si02, was later (1912) revised as 3CaO.2Si02. This 
is again revised and now the orthosilicate 2CaO.. SiO; is used in calculating 
the norm. A table is given which may be cut out and pasted over the 
akermanite table given in the C.I.P.W. book. 
WASHINGTON, HENRY S. ‘The Correlation of Potassium and 
Magnesium, Sodium and Iron in Igneous Rocks,” Proc. Nat. 
Acad. Sci., I (1915), 574-78. 
The writer shows that in igneous magmas potassium and magnesium 
on the one hand and sodium and iron on the other probably vary 
together. 
WASHINGTON, H. S., and Day, ARTHUR L. ‘Present Condition 
of the Volcanoes of Southern Italy,” Bull. Geol. Soc. Amer., 
XXVI (1015), 375-88, pls. 9. 
A record of the state of activity and other conditions at Vesuvius, 
AXtna, and the Aolian Islands during the summer of 1914. The general 
results of the observations and studies of gases, salts, and rocks collected 
will be given in a subsequent paper. 
Watson, THomMAS L., and TABER, STEPHEN. ‘‘Magmatic Names 
Proposed in the Quantitative System of Classification for Some 
New Rock Types in Virginia,” Bull. Phil. Soc. Univ. of Virginia 
Scientif. Ser., I (1913), 331-33- 
Proposes four new names in the C.I.P.W. system, for rocks found in 
Virginia. 
