578 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



Osnabriick, Hanover, Prussia. Their immediate associate is limonite, 

 resulting from the alteration of siderite, which is regarded by Haar- 

 mann,'^ who studied the geology of the region, as a metasomatic 

 replacement of Permian limestone. 



Pseudomorphs of marcasite, after pyrrhotite, have been noted in 

 only a few instances, and chiefly at German localities that have been 

 studied in the utmost detail. From Freiberg, Saxony, such pseudo- 

 morphs have been known for a long time. In 1849 marcasite, having 

 the hexagonal prismatic form of pyrrhotite, was described by Breit- 

 haupt ^ as occurring with other sulphides in the "Neugliick," "Drei 

 Eichen," ''Alte Ehzabeth," "Segen Gottes," "Herzog August," 

 "Besheert Gliick," and other mines of this district. Breithaupt's 

 description was quoted by Blum <= in 1852; the occurrence noted by 

 Frenzel "^ in 1874; the faces stated by Groth ^ in 1878 to be (0001) and 

 (1010), with an occasional steep hexagonal pyramid; and, finally, the 

 various accounts summarized by Hintze / in 1904. At Nagyag, Sie- 

 benburgen, Prussia, according to Blum,^ marcasite has been found on 

 dolomite in hexagonal tablets, consisting of base, prism, and pyramid, 

 with the side faces horizontally striated, and coinciding in habit with 

 the pyrrhotite occurring at the same locality. 



Rumpf,^ in 1870, described pseudomorphs of marcasite after pyr- 

 rhotite from one of the iron mines at Loben, near St. Leonhard, 

 Carinthia, Austria, found, according to Weinek,* in a druse at the 

 contact between siderite and limestone. These are rosettes of thin 

 tabular crystals with smooth, regular, lusterless faces, comprising a 

 base, hexagonal prism, and occasional fairly steep pyramid, and were 

 mistaken by Reuss^' and Weinek*^' for pseudomorphs after hematite. 

 Doll,* in 1874, briefly mentioned tabular pseudomorphs occurring on 



oE. Haarmann. Die Eisenerze des Hiiggels bei Osnabriick. Zeitschr. fur prakt. 

 Geol., vol. 17, 1909, pp. 343-353. See also Stockfloth. das Eisenerzvorkommen am 

 Hiiggel bei Osnabruck., Gliickauf, 1894. 



&A. Breithaupt. Paragenesis, 1849, pp. 130, 161-164, 170, 253. 



c J. R. Blum. Pseudomorphosen des Mineralreichs, 2 Nachtrag, 1853, p. 74. 



d A. Frenzel. Mineralogisches Lexicon fiir das Konigreich Sachsen. Leipzig, 1874, 

 p. 201. 



fi P. Groth. Die Mineraliensammlung. Strassburg, 1878, p. 45. 



/C. Hintze. Handbuch der Mineralogie. Leipzig, vol. 1, 1904, p. 637. 



fifj. R. Blum. Pseudomorphosen des Mineralreichs, 3 Nachtrag, 1863, pp. 192-193. 

 This locality was noted by V. R. v. Zepharovich, Mineralogische Lexicon fiir das 

 Kaiserthum Oesterreich, Vienna, 1873, p. 202. 



'^ J. Rumpf . Ueber den Magnetkies von Loben bei St. Leonhard in Karnten. Verh. 

 k. k. geol. Reichsanst., Wien, 1870, pp. 2, 3. 



i F. Weinek. Markasit nach Eisenglanz von Loben. Verh. k. k. geol. Reichsanst., 

 Wien, 1867, p. 285. 



jA. E.Reuss. Markasit, pseudomorph nach Eisenglanz. Verh. k. k. geol. Reich- 

 sanst., Wien, 1867, pp. 218, 219. 



^ E. Doll. Neue Pseudomorphosen. Tschermak's Min. Mitth., 1874, pp. 85-88. 



