CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
37 
3. MISCELLANEOUS ROCKS. 
A. Keratophyr, Marblehead Neck. Lif arose. Described by Scars, 
in Bull. Museum Compar. Zoology, vol. 16, No. 9, p. 1T(). Contains 
crystals of feldspar, with a decomposed base, irregular patches of 
quartz, some scales of biotite and grains of magnetite, and also some 
limonite and earthy matter. The feldspar is anorthoclase. 
B. Feldspar, separated from A. Analyses A and B by T. M. 
Chatard, record No. 1176. 
C. Highly metamorphosed feldspathic conglomerate, graduating 
into arkose-gneiss, electric railroad cut, Marlboro. Analysis by 
George Steiger, record No. 1536. 
D. Phonolite, Southboro. Miashose. Analysis by H. N. Stokes, 
record No. 1653. Contains traces of chlorine and fluorine; 63.2 per 
cent of the rock is decomposable by hydrochloric acid. 
Rocks C and D were collected by B. K. Emerson, but have not been 
fully described. 
Si0 2 
ALA 
FeA 
FeO 
MgO 
CaO 
Na 2 
K 2 
H 2 at 100° . . . 
H 2 above 100 c 
Ti0 2 
C0 2 
PA 
so 3 
MnO 
BaO 
70.23 
15. 00 
1. 99 
undet. 
.38 
.33 
4.98 
4.99 
.91 
1.28 
(?) .03 
.06 
24 
100. 42 
B. 
65. 66 
20. 05 
trace 
trace 
.18 
.67 
6.56 
6.98 
.04 
.37 
undet. 
undet. 
13 
100. 64 
75. 35 
13.03 
.62 
.94 
.21 
1. 33 
2.44 
5. 14 
.15 
.73 
.21 
.03 
.08 
.03 
none 
.07 
100. 36 
54. 22 
20.20 
2.35 
1.02 
.29 
.70 
9.44 
4.85 
.42 
5.57 
.38 
trace 
.11 
none 
.19 
trace 
99.74 
