GREGORY.] 
ANALYSES OK TKSCIIENITKS. 
183 
The structure is, in a way, theophiticof the diabases, in that the feld- 
spars have crystallized before the augites, but the arrangement is not 
one where augite grains with common orientation fill the interspace- 
between the feldspar laths, but single large augite crystals are cut 
into, two or more separate parts by rodlike feldspars which penetrate 
them at different angles, and the effect between crossed nicols is some- 
what suggestive of poikilitic structure. An average of all the coarsely 
crystalline specimens would give a structure between the granitoid 
and that of ordinary diabases. It is indeed quite probable that all of 
(the essential components were in process of formation at one time. 
Analysis. — The following analysis (I) by Dr. W. F. Hillebrand, of the 
United States Geological Survey, was made from the freshest speci- 
men of the coarse crystalline variety from the dike cut through by the 
wagon road: 
Analyses of teschenites and related rocks. 
Constituent. 
I. 
II. 
III. 
IV. 
V. 
VI. 
VII. 
VIII. 
Si0 2 
AIA 
Fe 2 3 
FeO 
MgO 
1 CaO 
Na^O 
K 2 
H 2 0— 105° 
H 2 O+105° 
TiO, 
ZrO, 
•CrA 
VA 
NiO 
Mn<> 
BaO 
SrO 
Li 2 
PA 
CO, 
CI 
Fl 
FeS 2 
Total . 
Per cent. 
46.77 
14.91 
7.80 
4.90 
2.94 
6.30 
4.97 
2.37 
.92 
4.28 
2.31 
None. 
None. 
.02 
Trace. 
Per cent. 
44. 65 
13.87 
6.06 
2.94 
5.15 
9.57 
5.67 
4.49 
.96 
2.10 
.95 
Per cent. 
44.31 
17.20 
4.64 
3.73 
6.57 
10.40 
4.45 
3.64 
. 77 
3.30 
Undet. 
Per cent. 
47.67 
18.22 
3. 65 
3.85 
6. 35 
8. 03 
4. 93 
3.82 
.38 
2.97 
Undet. 
I'i ;' ci nl. 
48.18 
11.80 
9. 7!) 
5.90 
6.05 
7.50 
3. 46 
1.57 
| 3.20 
I'i r a ui. 
49.61 
19. 18 
2.12 
5.01 
4. 94 
10.05 
5.62 
1.01 
3.55 
Percent. 
46.48 
16. 16 
(i. 17 
6.09 
4.02 
7. 35 
5.85 
3.08 
4.27 
.99 
Per cent. 
46. «)«> 
17.94 
2.56 
7.56 
3.22 
7.85 
6.35 
2.62 
.05 
2. 92 
.29 
.04 
.03 
Trace. 
.98 
Trace? 
Trace. 
({. 036 S) 
I .07 
.17 
.76 
.37 
Trace. 
1.50 
.11 
Trace. 
.10 
.28 
Trace. 
None. 


.49 
.71 
Trace. 
.27 
. IT. 
.01 
(S0 3 .61) 
99.90 
99.92 
99.11 
100. 15 
98.65 
L01.39 
100. 91 
99.60 
