Geology and Natural History. 501 



philite (cf. this Journal, xxxiii, 423) by Mierisch, which is from 

 the same locality and is doubtless the same mineral. 



Paposite. — A hydrous iron sulphate from the Union mine near 

 Paposa, Atacama. It occurs in dark red crystalline masses hav- 

 ing a fibrous radiated structure. Its composition is expressed by 

 the formula 2Fe 2 3 . 3S0 3 . 10H 2 O. Darapsky, Jahrb. Min., i, 23 

 ref., 1889. 



7. Mazapilite. — Dr. Koenig has continued his investigation 

 of this species from Mazapil, Mexico (see vol. xxxvi, p. 391). It 

 proves to be orthorhombic with a prismatic angle of 119° 50'. 

 An analysis gave : 



As 2 5 Sb 2 5 P 2 5 Fe 2 3 CaO H 2 



43-60 0-25 0-14 30-53 14*82 9'83 = 99-17. 



It thus approaches very close to arseniosiderite, and may be iden- 

 tical with it. — Proc. Acad. Nat. Sci. Philad., 45, 1889. 



8. Gahnite, Columbite. — Dr. Genth describes gahnite from 

 Smedley's quarry, Delaware Co., Penn., and columbite from Mineral 

 Hill. The latter mineral is especially interesting as being a nearly 

 pure niobate with Nb 2 5 76-26 p. c, Ta 2 6 0'83 p. c. ; the specific 

 gravity, 5 -2 6, is correspondingly low. — Proc. Acad. Nat. Sci., 

 Philad., 50, 1889. 



9. Stibnite from, Canada. — In the Annual Report of the Ge- 

 ology of Canada for 1887, G. Ch. Hoffmann, chemist to the Sur- 

 vey, announces the occurrence of stibnite at Foster's Bar, about 

 23 miles from Lytton, Br. Columbia. 



10. Mineralogy of Pennsylvania, Part I. Easton, Penn.— 

 Professor John Eteeman has prepared this pamphlet as a con- 

 tinuation of Dr. Genth's volume on the same subject issued in 

 1875. The finding of euxenite is announced, but from an unknown 

 locality, also of erythrite at the French Creek mines. The follow- 

 ing analysis is given of the calamine from Friedensville : SiO a 

 24-32, ZnO 65-05, H 2 7*86, Fe 2 3 2 12 = 99*35. 



11. Note on Sinter-forming Algw. — A collection of Algse from 

 the hot springs of the Yellowstone National Park, has been placed 

 in the hands of Professor W. G. Farlow, for examination. The 

 result of his study will be published on the completion of the 

 work together with such facts concerning the occurrence of the 

 plants as Professor Farlow may care to use. The specific deter- 

 mination of Calothrix, and of Leptothrix, given in the article on 

 the " Formation of Siliceous Sinter," in this volume, were not 

 made by him, and are subject to correction in his report. 



W. H. WEED. 



12. Results obtained by etching a sphere of quartz and crystals 

 of quartz with hydrofluoric acid / by Dr. Otto Meter and 

 Samuel L. Penfield. — Starting with a sphere of quartz, shown 

 by its pyro-electrical behavior to have been cut from a simple 

 right-handed crystal, the authors have studied the effects of ex- 

 posing it to the action of hydrofluoric acid for different periods 

 from four days to eight weeks. Two excellent plates reproduce 

 with wonderful fidelity the delicate etchings exhibiting the tetar- 



