358 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
In my examination I failed to find any evidence of the northwesterly 
dip described by Wadsworth, and a subsequent examination by Mr. W. M. 
Chauvenet with Wadsworth’s description in hand was equally futile. The 
reddish bands, as stated above, showed, so far as I observed, no one direc- 
tion of inclination any more decided than the others, and even if they did, 
it would be necessary for any one trying to establish their direction as that of 
the general bedding of the rock, to prove that they should not rather be taken 
as instances of the cross-bedding so commonly affecting the similar sand- 
stone of the Mississippi Valley, while both they and the larger clay bunches 
are precisely what may be seen in the plainly horizontal sandstones of the 
Apostle Islands. It would seem that Mr. Wadsworth, having previously 
formed a theory as to the relation of the Eastern Sandstone to the Kewee- 
awan beds, has felt it necessary to explain away the plain horizontality 
of the rock in this quarry. 
A similar process has led him to the view that the feldspathic ingredient 
has been leached out of the Eastern Sandstone, in order that he may explain 
the quartzose character of this sandstone and of that of the Douglas Hough- 
ton and Hungarian rivers—a character which is in fact a common one of the 
Eastern Sandstone, wherever met with on the line between Béte Grise Bay 
and Lake Agogebic, and again along the north face of the South Range east 
of Lake Agogebic. This leaching process would have but a slender theo- 
retical basis at the best, and in the present case seems to be distinctly dis- 
proved by the appearance of the thin section, nearly the whole of which is 
formed of rounded quartz grains without any space for the feldspathic material 
to have been leached from; while the few feldspar grains present are singu- 
larly fresh for the grains of a fragmental rock. Moreover, the quartz particles 
cannot represent a secondary substitute for feldspar, such as so often occurs 
in the granitic porphyries of the Keweenaw Series. I cannot conceive of a 
leaching process which leaves neither space nor substitute for the original 
material. Possibly it is meant that the leaching has affected the rock as a 
mass, and that the remaining material has collapsed. But this could not 
happen so as to leave the rock so distinctly marked by the original bedding 
structure. The thin section shows, moreover, the quartz grains frequently 
in the often observed relation which indicates that they lie where rolled 
