Reviezv of Recent Geological Literature. 325 
fluorine determinations have not hitherto been confirmed, are shown to 
be correct. The analyses show some 40 per cent of Cca O3 (including 
Th02), with a little less of the La group. 2. Prosopite. A beautiful 
pale green mineral from Utah, supposed by Kunz to be utahlite, proved 
on analysis to be prosopite, mixed with quartz and flourite (?), and 
colored by some copper salt. Comparison with Altenberg and Pikes 
Peak prosopites shows a close agreement except in amounts of F and 
HgO, the variation of these two aflfording further evidence as to their 
mutual replacement by one another. 3. Jefifersonite. An analysis 
of a brown mineral from Franklin Furnace, N. J., agrees closely with 
that of jefifersonite but its physical properties differ from hitherto pub- 
lished data of that mineral. The author considers the analysis chiefly 
valuable as showing a wide range of composition for the mineral. 4. 
Analyses are also given for covellite, enargite, and a blue stalactite 
from Butte, Montana, and a fibrous sulphate corresponding to the em- 
pirical formula (FeMn). (ZnMg), Al2(S04)9 65H.O from near White- 
hall, Montana. m. l. f. 
On the Chemical Composition of Tourmaline. By S. L. Penfield 
AND H. W. FoOTE. Am. J. Sci., 157, 97-125. 
This important mineralogical contribution consists essentially of an 
elaborate review and critical discussion of the investigations of Rani- 
melsberg, Riggs, Jannasch and Kalb, and others upon the constitution 
of tourmaline. Two new and carefully executed analyses are given 
which agree closely with those of previous investigators. Rammels- 
berg's conclusion that all tourmalines are derived from the acid HoSiOs 
was based on analyses which the authors have shown to be defective. 
On applying the necessary corrections, however, the general formula 
H2oB-Si40:i may be derived, which agrees with that obtained by Riggs, 
Jannasch and Kalb, and the authors. A critical examination of the 
many published analyses, taken in connection with their own analyses 
of exceptionally pure specimens, leads the authors to the conclusion 
that all varieties of tourmaline are to be considered as salts of the acid 
HaAl3(B.OH),.Si40;i, in which the complex aluminium-borosilicic acid 
radical exerts a mass effect by virtue of which the remaining hydro- 
gens may be replaced by numerous metals of essentially different char- 
acters without any pronounced efifect on crystalline form. The table of 
the ratios R': R" : R"' : H, derived from some 35 analyses, includ- 
ing practically all varieties thus far investigated, shows that although 
certain prominent types undoubtedly exist, the ratios do not approach 
closely enough to rational members to give definite formulas. 
M . L. F. 
Notes on North Carolina Mitterals. By J. H. Pratt. J. Elisha 
Mitchell Sci. Soc, 14, pt. 2, 61-83. 
The notes on four of the nine minerals considered in this article, 
wellsite, anorthite, cyanite and zircon, have been published elsewhere 
and noticed in this review. The remaining species are chabazite, an- 
thopyllite, enstatite, enstatite (bronzite), and emerald beryl. The chab- 
