Geology and Mineralogy. 403 
=m aaa and schists, that of conformability between them is 
e most relied on b> geologists, and the most decisive. r. 
Wadsworth has sennideven it with reference to the Marquette 
iron ore, and, disagreeing with other observers, has decided the 
question adversely. But geologists who have studied, with that 
and other cen in view, the widest range of Archean iron 
Miretetee included, are conformable in bedding, and hence has 
they are metamor ‘phous seus ientary deposits. My own exami- 
nations on this point, at a in New Jersey, New York and 
Connecticut, have confirmed me in the same view; and, 
others, I believe it will be fen d that any apparent unconfor 
these oldest of maa have under ee 
4. On the Jasper and Iron One: of the Marquette Region 5 by 
M. E. Wapswortru.—In the Marquette region, the country rock 
is of a varying nature, but is mainly composed. of schists Corgely 
chloritic), argillites, and quartzite, in that part of the district 
visited by us. Associated with these rocks is the jasper, which 5 is 
The irregularity of the ore mass, its passage into the jaspery ores, 
and the uncertainty where the ail mass will be found, are 
among the chief difficulties of the miner. The Ati of the jas- 
per and ore becomes then a robles of great economic import- 
ance, as do also the relations of both to the ontey rocks. The 
permanence and extent of the formation, whether it is in the form 
w) masses, or sedi- 
mn re $ vel 
only the question whether the jasper ei its seaaeiatil ores are 
ast cp or sedimentary in origin. 
est there be some misunderstanding as to the reason for thus 
dismissing the theory of the ores here being vein deposits, we 
