O’Rem1ty— Anatase and Brookite in Quartzites of Shankill. 737 
that is, an anatase in which a certain amount of TiO, is replaced 
by alumina, as it is frequently by Si0,. 
Keiihawite bears to it aresemblance only in so far as it isa 
titano-silicate of CaO, Al.O;, Fe.0;, and Y.O; the density being 
3°52 to 3°77, but the crystalline form (monoclinic) and the other 
characteristics differentiate it markedly. It suggested, however, 
that the alumina might be accompanied by some of the rarer 
earths. An analysis was undertaken for the determination of the 
presence of such rare earths, but the results were negative. In the 
same edition of Dana, mention is made, on p. 716, of a mineral 
called Xanthitane, of which the following details are given by 
Eakins whose analysis thereofis also given. He considers it as an 
alteration product after Titanite. He gives the colour as light 
yellow, and says it was mixed with impurities to an undetermined 
extent. He calls it a clay containing titanium in place of 
silicon, and states that the analysis given is of a material obtained 
from Green River, Henderson Co., N. C. (U.8.A.). It isinteresting 
to place his analysis side by side with that of the Shankill anatase 
by Mr. Warren. 
Xanthitane. Shankill 
Anatase. 
Percentage. Percentage. 
S$i02., . 5 5 1-76, ; a 3°30 
Al2,03, : . . 17°59, . . . 12°86 
FeO, . : : — : ‘ a l5=20 
Fe203, . < ; 4:46, 3 4 . 1:05 
CaO : ‘ 0-90, ‘ ‘ : 2°29 
MgO, . 4 . _ traces, : é : 4°49, 
MnO la: : : —_ 9 3 . traces 
TiO 5 . 61°54, 3 3 - 60°72 
Ph20;, 4 ° = 4: We O e 3 —_— 
H20, 5 A 9°92, : ; 5 0:06 
(K20 and Na20), . = ey ; ; 0:06 
100°34 99-96 
There is an evident resemblance between these two analyses, so 
much so, that it might be presumed that the yellow earthanalysed by 
Eakins from Green River, Henderson Co., U.S., was most probably 
the product of the decomposition of an anatase mass having origi- 
nally had the same composition as that of the Shankill specimen or 
nearly so. 
Subsequently to the analysis of the crystals, Mr. Warren made 
