( 549 ) 
1 
II 
HI 
IV 
V 1 VI 
Si0 2 
TiO, 
Al s Oj 
FeA 
FeO 
MnO 
CaO 
MgO 
Na,0 
KaO 
PA 
h 9 o 
7 
9 
7 
3 
20 | 
13 1 
23 
73 
55 
35 
20 
20 
49.70 
1.33 
18.45 
3.39 
4.32 
7.91 
2.32 
5.33 
0.40 
1 34 
51.10 
1.38 
21.10 
0 90 
5.58 
5.35 
1 2.81 
6.35 
4.21 
0.87 
47.67 
18.22 
3.65 
| 3.85 
0.28 
8.03 
6.35 
4.93 
3.82 
2.97 
44.65 
0.95 
13.87 
6.06 
2.94 
0.17 
9.57 
5.67 
4.49 
2.10 
1.50 
47.85 
13.24 
2.74 
2.65 
14.36 
5.68 
3.72 
5.25 
2.74 
2.42 
99 
85 
99.44 
99.65 
100.15 
99.93 
100.65 
I. Pienaarite. Leeuwfontein (320) Pretoria. Transvaal. 
II. Covite. Magnet Cove. Arkansas cf. H. S. Washington. Joum. 
of Geol. IX. 614. 1901. 
III. Covite. Nosy Komba. cf. A. Lacroix Mat. Mineral. Madagascar 
Extr. Nouv. Arch, du Museum 4e Ser. I. 32. 
IV. Teralite. Crazy Mountains Bull. U. S. Geol. Surv. no. 150. 
V. Teralite. „ „ „ » » » ” ” ” 
VI. Teralite. (nepheline pyroxene malignite) cf. A. C. Lawson Bull. 
Dep. of Geol. Univ. of California I. 337. 1896. 
We see how the rock, here described, differs in mineralogical and 
chemical composition from the melanocratic nepheline syenites, which 
are hitherto known, its characteristic features are the large amount 
of FeA, TiO„ and CaO (abundance of aegirine, aegirine-augite 
and titanite) and its low content of lime (diminuation of the felspars 
and felspatoids). Prof. Molengraaff proposed to me the name Pienaarite, 
after the Pienaarsriver because the locality, where he collected this 
rock, is situated in a region between a tributary of the Pienaarsriver 
called Mundtspruit, and the above river itself. 
37 * 
