IGNEOUS AND CRYSTALLINE ROCKS. 21 
99. 78 7 F 
3.220,21.5°| 2.667, 24° |........ 3.217,29° | 2.677, 22° 
100. 51 | 100. 46 99. 12 | 100. 62 
3. MISCELLANEOUS ROCKS. 
A. Keratophyre, Marblehead Neck. Liparose. Described by Sears, in Bull. Mus. 
Comp. Zool., vol. 16, No. 9, p.170. 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. P. R. C. 1491. 
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. P.R. 
C. 1637. 
D. Agirite tinguaite, Southboro. Miaskose. Analysis by H. N. Stokes, record 
No. 1653. Contains traces of chlorine and fluorine; 63.2 per cent of the rock is decom- 
posable by hydrochloric acid. P. R. C. 1639. 
Rocks C and D were collected by B. K. Emerson, but have not been fully described. 
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E. Massive, coarse, altered diabase, Leverett. Ornose. Contains saussuritic 
feldspar with black hornblende. Analysis by Eakins, record No. 1325. P. R. C. 1640. 
F. Tonalite, South Leverett. Andose. Dark green, chloritic. Contains reddish 
feldspar, dark hornblende, and a network of dark-green epidotic quartz veins. 
Analysis by Eakins, record No. 1326. P. R. C. 1641. 
15619—Bull. 419—10——3 
