50 The American Geologist. July, i897 
to transport even ten feet, the remaining nine-tenths. Fur- 
ther, we found that this conglomerate graduates into a quart- 
zyte, and into a graywacke and that tlie gray waelce graduates 
into argillaceous slate, these latter constituting, with the con- 
glomerate, an upper formation nonconformable on the iron- 
bearing formation. 
This discovery not only corrects Messrs. Smyth and Finlay, 
but corrects also the Minnesota survey, for the Minnesota sur- 
vey had not before recognized this plane of non-conformity, 
although it had been claimed to exist in that region b}' Prof. 
C. R. Van Hise of the United States Geological Survey. 
The importance of this discovery is so great that it is not 
possible to discuss its effects on the structural geological 
scheme of the state at this time. Whether this break in the 
stratification be a northern representation of that which ex- 
ists at the base of the Taconie, or an older one which thus 
would really make an important new formation in the Arch- 
ean, is not yet ascertained. 
3. There remains now the third point which I will allude 
to but briefly, viz : the nature (incl position of the conglomerate 
in the Pvckwunge valley. 
North from Grand Portage village is a stream entering the 
Pigeon river from the west which the Indians call Puckwun- 
ge. Along the side of this valley is a conglomerate and 
quartzyte, in the northern slopes of the hills which form the 
southern barrier of the valley. This conglomerate, which has 
been twice examined, remained until the recent visit, some- 
what of a puzzle. It is not where a conglomerate has been 
expected. It undoubtedly forms the base of a formation, 
either of the Animikie or of the Keweenawan. It is overlain 
by igneous rocks resembling the traps of the Keweenawan. 
What it exactly lies upon we could not find out, but in a low- 
er level in the same hills is a singular-looking and somewhat 
slaty rock which we named the Puckwunge slate. This slate 
is an important formation. It extends far northward, at least 
across the Puckwunge valley, and eastward. It forms the 
outcropping rock seen at several places on the Grand Port- 
age trail, except near Grand Portage village where the usual 
features of the slaty Animikie are seen. The drift is rather 
heavy in the region, and it was only by general taxonomic 
