PETROGRAPHIC GEOLOGY AND DESCRIPTIONS. 749 



Cak'ite and gray wacke. Iron ore.] 

 Greenstone. 



Mir. The calcitc here is more granular, massive, and mingled evenly with a 

 certain amount of fine debris, apparently of fclihpar and quartz. One section. 



Age. Animikie. N. H. w. 



No. 1611. CALCITE. ( Griiti/. } 



Calcareous nodule from the slates at Carlton, east of the depot, north of the railroad, ten to twenty feet 

 ;il)ovr the railroad (jradc. 



. Annual Report, xx, pagr .'*; 



Met/. Even grained, dark, apparently gritty. 



Mic. The slide shows large interlocking calcites, in which are scattered angular 

 '/i/tirtz grains and feldspar fragments. Two sections. 



Age. Animikie. 



liriiutr/c. The presence of this rock debris in these nodules rather precludes 

 the assignment of them to any organic agency. N. H. w. 



No. 1616. CALCITE AND GRAYWACKE. 



Two miles north of Thomson, near the St. Louis river. 

 Ref. Annual Report, xx, pages 29, :>-J. 



Meg. One of the calcareous, rusty- weathering nodules, from the.slate formation 

 at this place. Compare Nos. 1607, 1609 and 1611. This specimen seems to be com- 

 posed of graywacke cemented by calcite. No section. 



Age. Animikie. u. s. G. 



No. 1618. IRON ORE. (Magnetic.) 



"Ore from the narrow magnetic belt on Camp's land, S. W. % sec. 33 [T. 63-12 W.], about a mile south- 

 west of Ely." 



Ref. Annual Report, xx, page 34 ; Bulletin vi, page 202.* 



Met/. Soft, black, slaty, magnetic and graphitic iron ore with lenses of jaspilyte. 

 No section. 



Age. Archean (Keewatin). r. s. G. 



No. 1(519. IRON ORE. 



Same place as No. 1G18. 



Ref. Annual Report, xx, page 34 ; Bulletin vi, page 202. 



Meg. Rather pure, but somewhat porous, iron ore consisting largely of hematite. 

 The mass is magnetic, but when powdered only a few grains are attracted by a hand 

 magnet. No section. 



Age. Archean (Keewatin). u. s. G. 



No. 1621. GREENSTONE. 



S. W. >4 sec. 33, about a mile southwest from Ely. In the midst of an indefinite greenstone is a harder 

 and apparently a more siliceous area which still is visibly a portion of the same rock; from this harder mass 

 this sample is taki-n. 



Ref. Annual Report, xx, page 34. 



*By a typographical error this rock is referred to in Bulletin vi as No. 1613 instead of No. luls. 



