W. M. Fontaine—Mesozoie Strata of Virginia. 229 
Triphylite. Lithiophilite. 
: (4.) Branchville (5.) Branchville 
(1.) Bodenmais. (2.) Norwich. (8.) Grafton. (Penfield), (Wells). 
P0; 43°18 44°76 44°03 45°22 44°67 
FeO 36°21 26°40 26°23 13°01 
MnO 8°96 17°84 18°21 32-02 40°86 
CaO 10 24 9 Sie we 
MgO 83 47 5 mae J 
Li,O 8°15 9°36 8-79 9°26 8°63 
Eo iat S 3 ects 32 i Soke 
Na,O 6 "35 29 14 
H,0O 87 “42 1°47 17 82 
Gangue “83 fs ig a siti 29 64 
99°39 99°84 100°70 100°20 99°78 
This series of analyses shows in a very striking way the trans- 
itions from triphylite, the phosphate of tron and lithium, to lithi- 
ophilite, the phosphate of manganese and lithium; to the first 
belongs the formula LiFePO, and to the second LiMnPO,. 
| In closing this paper I wish to acknowledge my indebtedness 
__ to Professor George J. Brush, who has most liberally furnished 
me with the material needed for my examination. 
Sheffield Laboratory, Dec. 16, 1878. 
Art. XXVIII.—Notes on the Mesozoic Strata of Virginia; by 
Ws. M. FontaIne. 
[Concluded from page 157.] 
5 
o not however phair more than one series. 
The strata are well exposed at Richmond in the lowest points 
reached by the erosion of the streams. They occur here with 
