844 THE GEOLOGY OF MINNESOTA. 



[Grit. Iron ore. Taconyte. 



Remark. These greenish seams are apparently of the nature of a clasolyte, /. e., 

 clastic material which has entered fissures from above.* N. H. w. 



No. 2134. GRIT. (Breccia, volcanic.) 



Taylor's Falls, one block west of the public school building, about 175 feet above the river. 

 Ref. Annual Report, xxiv, page 45. 



Meg. Breccia of rock similar to No. 2129. 



Mic. Besides the quartz and epidote this slide contains what appears to have 

 been a fragment of lava, now nearly opaque with magnetite, in which are small 

 quartzes and epidote crystals (pseudomorphs after feldspar), with a background of 

 quartz(?) embracing the whole poikilitically. This epidote has not so much a clastic 

 aspect as that in No. 2129. One section. 



Age. Keweeuawan. N. H. w. 



No. 2135. IRON ORE. (Pisolitic.) 



Republic mine, sec. 4, T. 58-18, Mesabi Iron range. 

 Ref. Annual Report, xxiv, page 47. 



Meg. The ore is massive, siliceous, but shows in part a pisolitic structure. 

 Mic. Under the microscope the taconitic structure is quite apparent, some of 

 the round grains consisting wholly of microgranulitic quartz. One section. 



Age. Animikie (iron-bearing member). Compare Nos. 1294 and 1530. N. H. w. 



No. 2136. IRON ORE. (Pisolitic.) 



Mountain Iron mine, Mesabi Iron range. 

 Ref. Annual Report, xxiv, page 47. 



Meg. Not siliceous. Compare No. 1294. 



Mic. The ore grains are frequently hollow, or are formed by two shells of ore 

 which are connected in some places, with a vacant space, or two spaces at the 

 centre. The general shape of the ore grains is that of the taconitic greensand. 

 The ore is loose and soft, and crumbles readily into a finer powder or dust. The 

 centres of the grains sometimes contain quartz. Three sections. 



Age. Animikie (iron-bearing member). N. H. w. 



No. 2138. TACONYTE. ( Siliceous. ) 



Mountain Iron mine, Mesabi Iron range. 



Ref. Annual Report, xxi, page 160, rock b ; Annual Report, xxiv, page 47. Compare No. 1295. 



Meg. The quartzyte shows inclusions of darker ingredients. 



Mic. The groundwork is exceedingly fine and apparently consists, as usual, of 

 interlocking quartz. In the groundmass are the outlines of the usual taconitic 

 granules which are frequently stained with a little iron as well as by actinolite( ?), 

 more or less dimmed by alteration. There are irregular areas, and particularly the 



*M. E. WADSWORTH. Report of the State Board of Geological Survey (Michigan), for the years 1891 and 1892 [1893], p. 130. 



