74 COLORADO FEEBEEITE AND THE WOLFRAMITE SERIES. 



The following combinations were observed by the writer on the 

 ferberite from Colorado described in this report: 



cbamlf cbamlf r a>eo cbamlf 



cbamlf cbamlfo cbaml 



cbamlfa, cbamldjf truo cbamlf 



cbamlp cbamlMnfutHBujA cbamlRQnft 



cbamlp cbamlGMNLntHAso cbatllE 



cbamlRCHta cbamlftHuJA cbatH 



cbamlfu cbamltHuJ cbatd 



cbamlfcupo cbamlNnftjo cbat 



cbamlf Hwo cbamlR CQtA cbaltd 



cbamlfruo cbamlft HE EvJpD baltH 



cbamlrCFMf cbamlftHa>AA baltH 



cbamlf cbamlftEAA cbatH 



cbamlLnf cbamlFftwd 



By calculating the percentage occurrence for the 77 combinations 

 listed (the 39 given in the table and the 38 observed by the writer), 

 the forms of the wolframite group fall into three classes, as follows : 



(1) Prominent forms: 



Letter a 6 m c I f t 



Symbol (100) (010) (110) (001) (210) (Oil) (102) 



Per cent of occurrence 97 84 75 67 67 57 51 



(2) Less prominent forms: 



Letter a> o d y H s o 



Symbol (Ill) (111) (112) (102) (904) (121) (121) 



Per cent of occurrence 35 24 21 21 17 12 11 



(3) Rare forms: All the remaining forms, 35 in number. 



BIBLIOGRAPHY. 



1. Descloizeaux, A., Memoire sur les formes cristallines du wolfram: Annales chim. 



et phys., 3d ser., vol. 28, p. 163, 1850. 



2. Descloizeaux, A., Nouvelles recherches cristallographiques et optiques sur la 



forme clinorhombique du wolfram: Annales chim. et phys., 4th ser., vol. 19, 

 p. 168, 1870. 



3. Jeremejew, P., Wolfram- Krystalle im Vergleich zu den Krystallen des Columbite: 



Russ.-k. mineral. Gesell. St. Petersburg Verh., 2d ser., vol. 7, p. 301, 1872. 



4. Groth, P., and Arzruni, A., Ueber die Krystallform und die optische Eigenschaften 



des Wolframs und dessen Beziehungen zum Columbit: Poggendorff's Annalen, 

 5th ser., vol. 29, p. 235, 1873. 



5. Krenner, J. A., Wolframit aus dem Trachyte von Felso-Banya: Min. pet. Mitt., 



vol. 5, p. 9, 1875. 



6. Groth, P., Die Mineraliensammlung der Kaiser- Wilhelms-Universitat, Strassburg, 



p. 161, 1878. 



7. Bertrand, E., Sur la hubne*rite des Pyre'ne'es: Soc. min. de France Bull. 5, p. 90, 



1882. 



8. Seligmann, G.,Mineralogische Notizen, III; 12, Wolframit: Zeitschr. Kryst.Min., 



vol. 11, p. 347, 1886. 



9. Sandberger, F., Ueber Lithionitgranite mit besonderer Riicksicht auf jene des 



Fichtelgebirges, Erzgebirges und des nordlichen Bohmens: K. bayer. Acad. 

 Munchen, Math. -phys. Classe, Sitzungsber., 1888, p. 423. 



10. Penfield, S. L. (with Genth, F. A.), Mineral notea, No. 52: Am. Jour. Sci., 3d 

 ser., vol. 43, p. 184, 1892. 



