220 UNIVERSITY OF VIRGINIA PTJBL' CATIONS 



ture of the pyrophyllite and lack of evidence indicating the original mineral 

 from which it was derived, suggest more than the usual processes of resid- 

 ual weathering to explain the formation of pyrophyllite at the Georgia 

 locality. Structure and other conditions of occurrence strongly suggest 

 formation of pyrophyllite at this locality from solution, as the final stage 

 in genesis. Likewise the relations of hematite to the associated minerals, 

 as sho^\Ti more especiallj^ in the study of thhi sections, indicate that it was 

 formed in the zone of katamorphism. On the other hand the cyanite^and 

 in large part the rutile are regarded from microscopic evidence as products 

 of dynamic regional metamorphism, formed therefore under anamorphic 

 conditions. The very narrow "quartz veins which sometimes carry rutile 

 and hematite were formed under different conditions, probably as products 

 of the deep vein zone. 



Thus far the rather rare mineral lazuhte has been noted chiefly in quartz- 

 ite of different ages in separate crystals and in pockets and veins. It has 

 been observed in narrow veins in clay slate near Werfen in Salzberg, in 

 massive veins in quartzite in the district of Keewatin, Canada, and in 

 the iron mine at Scania in Sweden. These occurrences clearly indicate 

 formation of lazulite as solution deposits under katamorphic conditions. 

 The occurrence of lazulite at Graves Mountain as observed b}' the authors 

 was not in veins but as separate and grouped crj-stals and aggregates dis- 

 tributed through the rock in intimate association with cyanite and rutile. 

 The evidence thus far obtained at the Georgia locality is regarded by the 

 authors as indicating formation of the lazulite under the probable condi- 

 tions of dynamic regional metamorphism. 



LITERATURE. 



Dana, E. S. A System of Mineralogy, 1900, 6th ed., pp. 239, 692. 



Dana, J. D. Seventh Supplement to Dana's Mineralogy. Amer. Journ. Sci.. 1S59, 



vol. 28, pp. 128-144. For lazulite. Graves Mountain, Ga., see p. 1.38; 



rutile, p. 141. 

 Genth, F. a. Contributions to Mineralogy. Amer. Journ. Sci., 1854, vol. IS, p. 410. 



Corundum, Its Alterations, and Associated Minerals. Proc. Amer. Phil. 



Soc, 1873, vol. 13, pp. 361-406. 



Contributions to Mineralogy. Proc. Amer. Phil. Soc, 1882, vol. 20, pp. 



381^04. 

 Haidinger, M. W. Die Rutilkrystalle von Graves' Mount in Georgia, U. S. N. A. 



Sitzungsberichie Ak., Wien, 1860, vol. 39, pp. .5-9, 2 figs, of rutile crystals. 

 HiNTZE, C. Handbuch der Mineralogie, pp. 161, 829, 831, 1617-1618, 1622. 

 Hunter, C. L. Notices of the Rarer Minerals and New Localities in Western North 



Carolina. Atiier. Journ. Sci., 1853, vol. 15, pp. 376-377. 



