1 882.] Mineralogy. 6c g 



On the Stalactites of Luray cave.— A. E. Foote describes the 

 cave near Luray, Va., and states that the curving and twisting of 

 the stalactites was due to the fungi which grew upon their sur- 

 face, and so caused lateral growth of carbonate of lime. 



New localities for Gypsum. — H. C. Lewis reports Easton, 

 Penna. and Richmond Coal-field, Va., as new gypsum localities. 



New locality for Sphene.— A. E. Foote describes the new local- 

 ity for sphene at Egansville, Renfrew county, Canada, where 

 crystals weighing from twenty to eighty pounds occur in a vein 

 of apatite. A crvstal of apatite weighed 500 lbs. 



A new locality for Hyalite.— H. C. Lewis describes green hyalite 

 from Germantown, Pa. 



Note on Atitunite. — H. C. Lewis gives the optical characters of 

 the Philadelphia autunite. It is orthorhombic, with an optic axial 

 divergence of 24 . 



Crystalline cavities in Agate. — Theo. D. Rand exhibits speci- 

 mens of agate containing crystalline cavities once occupied by 

 calcite crystals. The method of taking type-metal casts of these 

 cavities was explained. 



Note on Halotrichite. — H. C. Lewis states two localities for 

 halotrichite. 



On twin crystals of Zircon. — A. E. Foote records the discovery 

 of twin zircon crystals at Egansville, Canada. 



Disks of Quartz between 'lamimc of Mica.— Theo. D. Rand ex- 

 hibits circular disks of quartz, showing a rotating black cross in 

 the polarizing microscope, which occur in muscovite from Amelia 

 county, Va. 



On two new localities of Colnw.bitc.—W. Carvill Lewis records 

 the occurrence of columbite at Mineral Hill, Pa., and at Dixon's 

 Quarry, Del. The crystallographic characters of the specimens 

 were described. 



On the occurrence of Fahluuite near Philadelphia.— U. C. Lewis 

 states that he has found fahlunite at two localities in hornblendic 

 gneiss near Philadelphia. It is of a pale apple-green color, and has 

 a scaly structure and felspathic cleavage. It resembles the variety 

 known as chlorophyllite, and appears to be a product of alteration. 



On a mine; ■•//,.• from a feat bed at Serautou 



Pa.—H. C. Lewis describes the black jelly-like substance from 

 the Scranton peat bed, already noticed in the Naturalist. 



Titauifcrous Garnet.— U. A. Keller describes a black garnet 

 from Darby, Pa., whose color is due to enclosed particles of 

 men 1 loMnik- and sphene, as shown both by microscopical exam- 

 ination and by chemical analysis. 



I\vrophv!litc and Alunoeyu in coal mines.— E. S. Reinhold states 

 that the coatings of pyrophyllite from the coal slates of Mahanoy 

 J-rty, already described by Dr. Genth, have now been found in 

 } our collieries. Other coatings have proved to be alunogen, the 

 0r igin of which is discussed. 



