Mineralogy and Geology. 123 
5. Addition to Prof. Shepard’s Notes on the minerals of the Emery 
mine at Chester, Mass., (see p. 112); by the Author.—I have just found 
the diaspore at Chester, in broad, nearly transparent white lamine, with 
a structure like that of kyanite, also of a most delicate violet color, deeper 
than that of Chemnitz. : : 
White massive corundum, in veins half an inch thick, occurs travers- 
ing the massive emery. The latter mineral at Chester is exceedingly 
uniform in composition, and may be regarded as an aluminate of protoxyd 
of iron, Fe Al. : 
A vein of Indianite, many inches thick, is found near the tunnel . 
South mountain, running for many rods through the chloritie beep the 
east side of the emery-vein (exterior to its gneissoid wall). This chloritic 
seam is called by the workmen “the fringe-rock.” — Small particles of 
erystalline corundum are diffused through the Indianite. 
Masonite (the variety near to ottrelite) is also abundant at many p — 
in the emery-vein on the North mountain. Brookite rarely attends the 
diaspore and corundophilite. 
emery on its eastern side. Indeed I regard this as the parent shies - - 
emery, out of which it was deposited when the strata were horizon . ) 
just as the emery of the Grecian archipelago and Turkey was segregate 
in fine limestone. 
er Ce i ‘ 
¢, Eocene; d, Cretaceous; @, Jarauat and Triassic ; 4; ee — 
stone and Devonian; g, Metamorphic schists ; h, Granite 9 ans ogi ; 
t, Eruptive rocks, not volcanic; &, Volcanic rocks ; N, naphtha a A e 
solfataras, mud volcanoes. The map is accompanied by a pamphiet de- 
7. On the Changes rendered necessary in the Geological Map of South 
Africa, by recent Di. erie Fossi , . aie 
Geol. Soc.}—_Dr. Rubidge first called attention to a former paper, in which 
he pointed out the occurrence of horizontal beds of sandstone resting 7 hike 
upturn ges of gneiss, and continuous with inclined sandstone 0! 
