158 The American Geologist. March, 20% 
the ore being scooped up by the steam shovel and dumped, 
without assortment or washing, upon the ore cars standing ad- 
jacent, and thence carried direct to the shipping point on lake 
Superior. But the mines on the Vermilion range are deep, 
underground, many-chambered excavations. The enclosing 
rock of the Vermilion range is a green-stone, usually alternat- 
ing with the iron ore sheets or strata, and varying to a strati- 
fied, water-laid rock showing plainly its oceanic origin. Al- 
ternations of strata of jasperoid silica with but little iron, with 
a green schist, or slate, are not an uncommon feature of the 
Lower Kewatin. The ore itself is a form of jaspilyte, a banded 
siliceous rock that occurs as lenses of greater or less size in the 
greenstone of the region. These bands are usually much con- 
torted, varying from pure white silica in very fine grain to 
brown, purple and black in proportion as the ores of iron share 
in their composition. Hence, they present a handsome out- 
ward aspect. Being firmer than the surrounding rock, such jas- 
pilyte lenses frequently stand isolated high above the surround- 
ing surface. These contorted lenses, which are the most valuable 
as ore bodies, seem to have the structure of rhyolitic lavas, the 
banding being due to an original fluidal structure, and it is in 
the periphery of these primary lenses that occur inter-lamina- 
tions of the fine silica with the green schists, denoting the action 
of sedimentation. Still, very large amounts of banded Jasperoid 
silica are apparently wholly of sedimentary origin, so far as the 
same is indicated by the straight banding, and by admixture 
with the green schists. On the Mesabi range the ore is in lenses 
as on the Vermilion range, but these lenses are of soft ore, and 
have a tendency to retire from observation. The lenses, more- 
over, are not composed of contorted laminations, but of 
straight or but slightly wavy strata, which can be seen to ex- 
tend from one end to the other. In these lenses the ore ceases 
to the right or left, or up or down in the stratification, by grad- 
ual change in the nature of the rock. This is not always by 
an increase in silica, which is the gangne impurity on the Ver- 
milion range, but by the encroachment of an impure ore known 
as taconyte. This taconyte is of two sorts, viz., (1) a sili- 
ceous granular rock, essentially like the ore itself but worth- 
less as ore because of the high per cent of silica, and (2) a 
gray or brownish amorphous rock which is neither ore nor 
