PETROGRAPHY. 
Chemical Composition of Bagnoreal Vicose [Leucite-tephrite]. 
97 
I. 
II. 
III. 
SiO, 
50.68 0.845 
so. 36 o 
830 
4Q. 73 
AL.O,. 
19.46 . 191 
17.62 
173 
Fe 2 O 3 
3.06 . 02? 
4.80 
O3O 
c . CQ 
FeO 
2 S3 
O3S 
MgO ., 
2 24 .056 
3 27 
082 
CaO 
6. 78 . 121 
7 6l 
136 
7 nfi 
Na 2 O 
2.61 .042 
I .00 
O32 
K 2 O 
9. 38 . ioo 
0. 30 
IOO 
93O 
H 2 O+ 
0.46 
I . IQ ) 
H 2 O- 
o. 16 
.. 
I.I9 
CO 2 
none 
none 
n d 
TiO 2 
0.89 .on 
i .09 
OI4. 
n d 
ZrO 2 
trace 
n.d. 
P 2 O C .. 
O. 33 . OO2 
o 40 
OO3 
n d 
SO 3 
none 
s 
none 
MnO 
n.d. 
n.d. 
n d 
CuO 
none 
n.d. 
BaO 
o. it; 
n.d. 
99.61 
100.25 
100.00 
SD BT . 
6e.e, 
* MgO by difference. 
I. Bagnoreal vicose [leucite-tephrite]. Poggio Cotognola, near Bracciano, Sabatinian Dis- 
trict. Washington, analyst. 
II. Bagnoreal vicose [leucite-tephrite]. Madonna del Riposo, below Bracciano, Sabatinian 
District. Washington, analyst. 
III. Bagnoreal vicose [leucite-tephrite]. Madonna del Riposo, below Bracciano, Sabatinian 
District. Washington, analyst. Jour. Geol., V, 1897, p. 49. 
Norm of I. Norm of II. 
Or 
. . 30 . 48 ) > 
1 35-3J 
77.65 ^'4 
9.09 \ 
o-35 ) 
21-19 l.ill 
1.44; 
0.96 
46.43 
25.22 
18.06 
8.44 
0.96 
7. 
-3.66 
| 71-65 
27.46 
II. 
2.61 
1.84 
3.22 
3-13 
An 
..13.62 S 53 
Lc 
. .12.62 ) 
Ne 
-.11.93 24 ' 55 
Di 
. .12.10 ) 
Wo 
Mt 
. S.8o ") 
11 
. I . S2 r 7. 32 
Hm 
. . O . OO ) 
Ap... 
. O 73 O. 73 
Rest .... 
98.84 
. O 77 
99.11 
1.19 
Class. . 
99.6l 100.30 
Ratios. 
Sal 
Order. . . . 
Fern 
F 
= 2.16 
= 2.90 
= 2.38 
"L 
K 2 O'+Na 2 O' 
CaO' 
K 2 O' 
' ' ' Na 2 O' 
