•It. 
i. 
II. 
II. 

A] .< » 
42.25 
16. 37 
" _ 
J9.72 
6.91 
3. 33 
3. 96 
77 
.43 
" ■- 
None. 
.03 
12.7 
.07 
.01 
.40 
NiO 
MnO 
1 . 30 

] • < 1 
11.40 
■ 
13.10 
\ 5. 08 
| 6. 50 
BaO Trace 
M-< - 

LLO 
None. 
Trace. 
.34 
None. 
•> 
(Traa - 
Trace. 

\"a 
P,O s . . 
1.30 
K « » 
B 0-105° 
BjO 


CI 
Fl 

Total 


99.84 
100.68 

Hill, Maine. Analysis by Dr. W. 6. Hiilebrand, United Slates Geo 
Sur. 
iburgite (magma basalt), Hone von Skalka, Bohemia. Analysis by Borieky,Math.-nar n 
Pmg, Jan. 12. 1872: eit. Jahrb. Min. 1872, p. 959. 
Discussion - '. — The above analysis ind ( basaltic 
magma between the gabbro and the peridotite groups. In the ab-> 
of crystallized minerals only theoretical compositions can be calcu- 
lated, but it is very probable that a magma so rich in n . and 
ferrous iron would form, on crystallization, much olivine, and. wit:, 
abundant alumina, augite also. These minerals would require all ( 
lime present, and hence feldspars containing the anorthite molecule 
could not b<- formed, but rather nepheline. or. if wa T 
analcite. In such a case the basic lamprophyric dike would be clag 
pheline-basalt or analcite-basalt. 
TESCHENITES. 
FIELD AFPE 
The field appearance of this rock i- cba tic, and a person with 
but -light acquaintance with igneous rock- would not confuse it with 
the other dike- or with the lava- of this region. But ii 
general characteristic appearance, it- variation within certain Limit 
remarkable, as h noticed in rock- of ti I rom other locali- 
ties So great - illation that at first sight the impi- 
conveyed that there are here a number of dik hat dim 
composition and structure which have inl I one anotb 
come up u- parallel intrusions. They are all par* 
