5o Editorial CoTwrnent. 
which may or may not be the deposition jDlanes, so far as we 
were able to determine — correspond in the main to the oblique 
contact face." Away from this immediate face, however, they 
found the same rock dipping northeast, and also lying horizontal. 
In the general section which is given to illustrate the situation 
on this stream the sandstones are represented as having an ini- 
dulating nearly horizontal position, and near the contact as being 
suddenly bent downward toward the northwest and so passing 
under the trap beds, which are shown to dip toward the north- 
west at an angle of about 35 '-' . 
Mr. Wadsworth has again visited this place and made further 
examination, the result of which he has given in Science for 
Sept. 30, 1887. He says "we were able to trace continuously 
the unchanged eastern sandstone into the sandstone which has 
been baked and indurated by the old lava-flow, and this baked 
sandstone into the lava-flow or melaphyr itself, all forming a 
continuous exjDOsed surface. There is no fault, or plane of sep- 
aration between the sandstone and the trap, but the two are 
welded together into one mass. * * * * The contact is 
that made by a lava-flow with an underlying sandstone, and is 
the same as the contacts so often seen within the copper-bearing 
series, while the sandstone is observed in situ to pass underneath 
the melaphyr." 
The authors review all previous opinions, and give their ob- 
jections to them. 
The yackso7z view^ so named from C. T.Jackson its author, 
is stated in four propositions. ( i). The eastern sandstones and 
the conglomerates and sandstones of the copper-bearing series 
are one and the same formation, and were once spread out con- 
tinuously in a horizontal position. (2). The traps of the cop- 
per-bearing series are all of them intrusive, having invaded the 
supposed sandstone formation in part as irregular intersecting 
masses, and in part in the shape of sheets which forced their way 
between the sandstone layers. (3). The conglomerates of the 
copper-bearing series derived their material by the ordinary 
aqueous agencies from some subjacent formation, which possibly 
ma}' have formed an old shore line in the immediate vicinity of 
Keweenaw point. More probably, however, the pebbles of the 
conglomerate have been sorted out, as it were, from the pre- 
