MINERJLLOGY. 237 



calcifce, incrusting flint implements and Roman bricks in connexion 

 with the conduits of the thermal springs of Bourbonne-les-Bains, like- 

 wise in the pisolitic limestone deposited by the hot springs of Hammam- 

 Meskontine, in the Province of Constantino, Algeria. The last 

 instance of recently formed iron-pyrites is due to the action of fresh 

 and salt water mixed, the mineral having been detected by Mr. Weston 

 in a fissure in a piece of wood forming part of H.M. Yacht ' Osborne.' 



a. A. L. 



Davidson, J. Analysis of Titaniferous Iron Sand from North 

 Berwick. Proc. R. Soc. Edinh. viii. pp. 523-525. 



A layer of the sand was found lying along the shore, derived from 

 trap tuffs traversed by dykes and veins of Basalt. The sand was highly 

 magnetic. Sp. gr. 4-6. II. E., Jun. 



Deane, Rev. Dr. G. The Minerals of the Bible. In Cassell's Bible 

 Educator. 4to. 



Delesse, Prof. A. Analyse d'un travail de M. J. D. Dana sur le 

 Pseudomorphisme en Serpentine. [Summary of Mr. J. D. Dana's 

 work on Pseudomorphism in Serpentine.] Bull. Soc. Geol. France.^ 

 3 ser. t. iii. pp. 179-181. 



Prof. Dana's paper is noticed in the Geological Record for 1874, 

 p. 228. 



Des Cloiseaux, M. Note sur la Forme cristalline et sur les Proprietes 

 optiques de la Durangite. [Crystalline Form and Optical Pro- 

 perties of Durangite.] Ann. Ghim. Pliys. ser. 5, t. iv. pp. 401- 

 406 ; 3 figs. 

 Examination of Mexican crj^stals of Durangite. The dominant form 

 is that of an oblique octahedron with rhombic base. The plane of the 

 optic axis is perpendicular to the plane of symmetry ; the acute 

 bisectrix is negative ; dispersion is feeble, with p>v. F. W. R. 



. Memoire sur les proprietes optiques birefringentcs caracteris- 



tiques des quatre principaux feldspaths tricliniques, et sur uu 

 precede pour les distinguer immediatement les uns des autres. 

 [The characteristic birefracting optical properties of the four 

 principal triclinic Felspars, and on a means of distinguishing them 

 immediately from one another.] Ann. Chim. Fhys. ser. 5, t. iv. 

 pp. 429-444, 7 figs. ; and Compt. Rend. t. Ixxx. pp. 364-371, 3 

 figs. ; N. Jahrh. Heft iii. pp. 279-284, 3 figs. ; Abstract, with table 

 by E. S. Dl ana], in Amer. Jom-n. ser. 3, vol. ix. p. 322. 

 An examination of the 4 triclinic felspars (albite, oligoclase, labrado- 

 rite, and aiiorthite) has led the author to suggest means for their dis- 

 crimination founded on the phenomena of double refraction. Details 

 are given and illustrated by figures. His conclusions oppose Tscher- 

 mak's views on the constitution of felspars. The employment of optical 

 means has corrected several determinations of felspar by other minera- 

 logists. The Moonstone of Mineral Hill, Pennsylvania, and the lamellar 



