conflicting Views of Lake Superior Stratigraphy. 121 



erate was deposited upon it. Fig. 2. is a section from south to 

 north, showing the relations described. The coarse conglom- 

 erate, in passing towards the north, varies into a fine con- 

 glomerate showing fragments of the same character, and this 

 into the ordinary vitreous quartzite of the region. 



Prof. "N. H. Winchell's* figure of this mine does not show that 

 he appreciated the manner in which the banded ore and 

 jasper abut against the conglomerate. Its lamination is 

 figured as regular and parallel to the foot -wall of the open pit, 

 whereas it is extremely contorted and often abuts against it, 

 while the conglomerate is represented as dipping at a fiat 

 angle away from the foot- wall, whereas the dip of the con- 

 glomerate is that of this wall. 



In the Goodrich locality this conglomerate belt has been 

 traced fully a mile east and west — that is, from the Saginaw 

 Mine, east of the Goodrich, to the Fitch Mine a considerable 

 distance west, and was noted by Brooks at the New England 

 Mine, about two miles east of the Goodrich. The conglomer- 

 ate, which is here so thick and prominent, is in most other 

 localities in the Marquette district much thinner and varies 

 quickly into the ordinary vitreous overlying quartzite, and 

 has therefore often escaped attention. Upon searching for 

 it, it has been found, however, almost everywhere in the Mar- 

 quette district, as the following list of mines will show. At 

 the Barron Mine near Humboldt, Mich., it is scarcely less con- 

 spicuous than in the Saginaw Range. It -has been observed 

 west of the Winthrop Mine ; for a distance of a mile and a 

 half or two miles along the Cascade Range, from the Cascade 

 Mine to the Wheat ; at the open pits of the Jackson Mine in 

 Negaunee; at the Lake Superior and Barnum mines of the 

 Ishpeming basin, as shown by diamond drill borings ; at the 

 Boston Mine, north of Clarksburgh, at the Spurr and Michi- 

 gamme mines, near the west . end of the Marquette Range ; at 

 the Republic Mine, the terminus of a long southern tongue of 

 the iron-bearing series ; and north of the east end of the 

 Cascade Range, about 1J or 2 miles west of Goose Lake. 



As pointed out by Professor Irving, since the fragments of 

 ore, chert and jasper are found in the conglomerate in pre- 

 cisely the condition in which they occur in the underlying for- 

 mation with their stratification lines running in every direction, 

 it is manifest that the latter had reached its present condition 

 before this overlying conglomerate was deposited. 



Whatever the origin of this ore and jasper of the Marquette 

 district is believed to be, it is evident that a time-break of 

 universal extent and of great magnitude occurs above it. 



* Geol. and Nat. Hist. Survey of Minn., 16th Annual Report, 1887, p. 46. 



