20 The Diabask Schists— H. V. Winchell. 
still seen the well marked, coarse conglomeritic structure which 
<ian be seen in it north of Tower in the Stuntz Island con- 
glomerate, and which is seen at intervals in the line of strike 
all the way to Ely. 
The bouMer-forms in this green rock become smaller and 
smaller until they are only an inch or a fraction of an inch in 
length. The entire rock for acres around is in many places 
destitute of any covering of drift or vegetation, and is seen to 
be composed of these elongated pebbles of greenstone. In many 
places even lio'e there are traces of sedimentary action in the 
arrangement of this basic material. 
Toward the north side of this greenstone-conglomerate 
ridge, in township 63-9, the rock becomes more massive. The 
schistose and conglomeritic structures fade out, and the rock 
instead of beiug fine-grained and soft, or almost amorphous, 
becomes firm, tough and finely crystalline. The crystals grow 
larger and the rock coarser and more massive until it forms 
hills and ridges of moderately coarse diabase. 
In the midst of this massive, basic, eruptive rock are found 
the large lenticular deposits of jasper and magnetite mentioned 
above. The contact between the jaspilyte and the diabase is 
everywhere abrupt and perfectly distinct. Masses of jaspilyte 
from the size of a pea to deposits a hundred feet thick and a 
quarter of a mile long are seen at innumerable places in sec- 
tions 5, 6, 7 and 8, 63-9. Many samples from this place show 
the nature of the diabase and the manner of contact. The 
diabase is usually quite fine and slightly schistose at the im- 
mediate contact; but a few feet or even inches away it becomes 
coarse and massive. Threads of the basic rock often penetrate 
into or cross entirely the jaspilyte masses. 
The strata of jasper and magnetite are here, as elsewhere, ex- 
cessively folded and contorted, but they appear to stand as a 
rule in vertical arrangement just as the jasper and hematite 
rock does at Vermilion lake. The jasper contains a larger pro- 
portion of dark-colored bands than farther west. 
The massive form and basic nature of this green rock are not 
the only evidences of its eruptive origin. The rock on the 
north and east sides of it, (for the diabase swings around so as 
to strike north and south, east of Snowbank lake,) is, or was, 
mica schist. Where this comes into proximity with the dia- 
