PETROGRAPHY. 
135 
of the specimens, the amount of this varying somewhat and never being large. There 
is also a very little soda-lime feldspar, in minute, stout prismoids, generally a few 
grains of olivine, and small grains of magnetite and needles of apatite. 
Chemical composition. Two analyses were made of rocks of this type, both 
specimens coming from the Hernican District. With them are given two other 
analyses of rocks from this area, though they are not altogether worthy of confidence. 
Chemical Composition of Saccal Albanose [ Leucitite]. 
I. 
II. 
III. 
IV. 
SiO 2 
46 . 2 7 O 
77l 
47. OS O 
784 
4.7 CO 
4O 27 
ALO, . 
17. 2C 
17.08 
167 
18 02 
1 7 60 
Fe 2 O, . . 
1. O4 
O2C 
3O4 
6 87 
FeO 
321 
4 80 
068 
2 O7 
MeO . 
$ 08 
e 67 
4 2O 
CaO 
II J.O 
2OJ. 
10 63 
189 
ii 66 
12. 77 
Na 2 O 
2.67 
i 61 
026 
i 84 
2. OS 
K 2 O 
8.58 
OOI 
7 C2 
080 
10 05 
";.i8 
H 2 O+ 
O 77 
7-5-* 
O 7T / 
H 2 O 
O I 7 
o. 72 
0.80 
CO 2 
none 
none 
TiO 2 
i ii 
OIJ. 
i i? 
OI4 
ZrO 2 
o. 01 
o 02 
P 2 Or . . 
o 70 
007 
O 17 
OOI 
O. ?! 
O. TO 
SO, . . 
trace 
none 
s 
none 
none 
CuO 
none 
O . 27 
NiO 
o.o<c 
MnO 
n.d. 
n.d. 
BaO 
o. 10 
o oo 
SrO 
o 06 
ioo. 61 
99.90 
ioo . 66 
IOI.o8 
I. Saccal albanose [leucitite]. Ticchiena, near Frosinone, Hernican District. Washington, 
analyst. 
II. Saccal albanose [leucitite]. Pofi, Hernican District. Washington, analyst. 
III. "Leucitite." Pofi, Hernican District. Speciale, analyst. Cf. Viola, loc. cit., p. ioo. 
IV. " Leucite-basalt. " Morolo, Hernican District. Viola, analyst. Viola, Neu. Jahrb., 
1899, I, p. 97. 
Norm of 7. 
An 
9 . 45 
Lc 
. 70 . 68 
Ne 
. 12 50 
Di 
Ol 
3-i4 
Am 
. 7. 27 
Mt 
11 
. 2.17 
Ap 
. 0.06 
Rest 
100.04 
0.60 
29. 
7-93 
0.96 
61.63 
38.41 
Or 
Norm 
. 7 
)} n 
.89 
9 6 
83 
68 
80 
96 
4i 
13. 
34 

20.85! 
39-SrJ 
3I-76 
6-54 
0-34 
An 
Lc . . 
- . 71 
Ne 
. 7 
Di 
2? 
Ol 
Mt 
4 
11 
2 
Ap . . 
o 
Rest . 
99 
i 
oo 
09 
60.36 
38.64 
100.73 
100.09 
