712 HENRY S. WASHINGTON 
the flows A and B the molecular amount of FeO is about four 
times that of Fe,O;, but in the dike C it is seventeen. In this 
respect the dike basalt resembles the basalts of the two submarine 
eruptions D and E, the former close to the harbor of Pantelleria 
and the latter about 33 miles to the northeast. It will be seen 
that C and D are almost duplicates, while E differs considerably 
in the silica and other respects. These relations of the iron oxides 
give rise to the idea that the ferrous oxide has been prevented 
from oxidation in the dike and the submarine eruptions—a point 
which has been discussed in a previous paper. 
Norms.—The norms of the Pantelleria basalts are as follows, 
those of the submarine ones having been given in the paper cited: 
A B Cc 
CDV aAR MMU Re sleaiat (nei ol RTS at aC ates, O22 6.67 Osu2 
AN SUT Nese eds cok ose eye iodine retica 28.30 28.82 28.82 
Pe awa MH Ea Ststericees hare Mee eli eye eur ce 20.02 14.73 1 87 
IN @ Cia eee acai) cs Ser eM re ayaa PAR Melhor nem atone re, Ma ett i ease ea 
DURA Na a A Saal cape mh) oe ei 18.81 19.54 18.77 
He Bea NN Daas orn alin Gai een ie Plc beacon ai ia ek an anata 8 8.06 5-74 
OUR H onan aed celina tata tee aNy aus Q.32 0.28 6.29 
INV Ate SUS Nees tape c onary ab aapee pe ne STE 6.03 TO DBD 
RSS aaa eee acs terror es ae nba ects 8.66 10.79 12.16 
GATTO UR RM eds canteens aN NET MES 2.02 3.36 3.36 
TRIES tis ee Re Alte geek a Nita aoe °.46 0.22 0.69 
100.88 99.66 99.80 
These norms place all three Pantellerian basalts in camptonose, 
III. 5.3.4, a subrang in which many basalts and gabbros fall. 
It will be noted that, in spite of the low silica, nephelite is not 
present in the norm, except to a slight extent in the Ferle rock, 
and it can hardly be said that these basalts have the trachy- 
doleritic character assigned them by Rosenbusch (p. 1357). It will 
also be observed that these norms correspond with the microscopic 
characters, the Ferle rock carrying considerable olivine, which 
is wholly absent from the Sant’ Elmo basalt. 
Mode.—It is impracticable to estimate the mode by Rosiwal’s 
method because of the fineness of the grain. Apart, however, 
from the small amount of alumina (to be taken from normative 
anorthite) which enters the augite the mode is essentially norma- 
