Geology and Mineralogy. 405 
cent to it will be found all that is left of the ore formation. This, 
wever, is not what Mr. Brooks intended in his statement, as 
these detrital rocks apparently form but a small portion of ‘his 
_uartzites. 0 sensi of course mark old beaches water-worn afte 
he jasper and ore were in situ, in nearly their present condition 
and, if the logic of the geologists of the Michigan and Wisconsin 
surv eys were carried out, these miiastath iets, sip ital formations 
would mark a new geologi cal 
At the upper portion of aie Jackson mine, Riise. i jas- 
r and hematite were seen to cut across and obliquely up 
through the schists. The jasper also curves in a similar manner 
at right angles to this nearly east and west section. While this 
could be explained easily by sedimentation, it is fatal to the view 
of conformable deposition. In pit No. 3 of this mine (Jackson) 
the ore breaks par Frees through the schist, forming a breccia- 
ted-looking mass, while in other cases it ater ah into the schist 
ending in irregular sobs 
In pit No. ta i e of ore fe jasper was seen satay be- 
tween and across the aes of the schist. In the “north 
pit” the oraplre character of the ore is van shown. Overlying 
the ore at a low angle isa iqiiateath containing jasper and ore. 
derived from its underlying ore. At the Home mine in the Cas- 
cade range the ore was largely a sandstone impregnated with 
hematite, strike N. 70° W. with a northerly dip, which varies 
owing to the contortion of the strata from 30° to 70° eral 
ere is no mistaking the intrusive character of the jasper and its 
interlaminated ore here. It is of course almost unnecessary to. 
state = this mine, having as its chief ore a ferruginous sand- 
ane, as sBirse since abandoned. The eneres* si porches 
kes cand little ctringoré of n nearly, pure hematite which, ‘in its 
of henge a 18 distinctly intrusive. While in general these 
Tei is advocated by Messrs. Credner and Brooks that all the iron 
drs originally in the state of magnetic oxide, this view being sus- 
ih by the crystals of martite found in various parts of the dis- 
it t would seem that a microscopic examination of the “see ts 
peng and ore should give us some facts bearing upon the ques- 
tion. A section was made of a finely-banded jasper on near 
