4 8 



Minnesota Academy of Science 



(5) This slide shows the ore, which is also called jaspilyte 

 when it is of low grade and distinctly banded by silica, alternating 

 with green schist, both standing vertical. 



Fig. 6.— Jaspilyte and Green Schist. Fig. 7.— Ore and Green Schist 



(6) This also shows the same structure. These were both 

 seen in the mines at Soudan, in the early stages of the mining at. 

 that place, and could have been repeated many times at all the 

 original openings. 



(7) This is another illustration of the same fact. In short, 

 in all the mines, whether at Soudan or at Ely, the grand structure 

 is the same. There are minor irregularities due to later fracturing 

 and displacement, but these can easily be seen to be local and of later 

 date than the orignal stratification. 



One singular structure was observed at the "Stone mine" at 

 Soudan which was appealed to by Dr. M. E. Wadsworth to show that 

 the jaspilyte is of igneous origin, viz., a so-called "dike" was seen 

 to diverge from the main jaspilyte mass, and to cut somewhat diag- 

 onally across the green country rock. The place where this jaspilyte 



Z>7a.ce- of the Trijvcipcd- Ore Mc&ss. 

 /"Milled* oxit'.) 



Shotting the plan and manner of divergence of the go-called 

 dike, at the Stone mine. SeujdcLn. . 



Fig. 9 — Ground Plan of the So-called Dike. 



Fig. 8 — So-Called 

 Dike of Jaspilyte 



spur, which consisted largely of good hematite ore, entered the 

 wall of the mine as it stood vertical, is shown by this slide. (Fig. 8). 



(8) Which was a drawing made on the spot. As this spur, 

 in its course, rose to the natural surface, its manner of divergence 

 was visible and the surface plan of the divergence was evident 

 and was also sketched as shown by the next slide. (Fig. 9). 



(9) In the light of what we know now it is apparent that this 

 diverging spur of jaspilyte is only the commencement of one of 

 those separate ore masses which spring up (in section) in the midst 



