82 The American Geologist. August, is95. 
(lig. 8) shows diabase overlying conglomerate and interstrati- 
fied sandstone. Between them is an obscure breccia. This 
conglomerate and sandstone dip 29° southwesterly toward 
a diabase clitf' about 50 feet distant which rises 40 feet. Some 
of the sandstone outcrops in the gorge are "indurated," as if 
by igneous contact. In general, however, the interpretation 
by Mr. Sweet sustains the view taken by Prof. Chamberlin. 
In the light of observations, however, some of which have 
been mentioned above, going to prove the pre-existence of 
conglomerate and sandstone, the facts that have been pub- 
lished relating to this locality will warrant the supposition 
that here we have to deal with two sandstones and two con- 
glomerates, one pre- and the other post-Keweenawan, and the 
remark of Mr. Sweet that in one of the conglomerates, i. e., the 
more friable one, some of the pebbles are themselves of a con- 
glomerate, much strengthens this hypothesis. The contrary 
dip of the conglomerates also sustains it. There can be no 
question, however, that the upper sandstone and conglomerate 
are later than the diabase at that locality. This seems to be 
proven by the existence of diabase pebbles disseminated 
through their fragmental materials as well by the difference 
of dip. How much later is not known. It may have been 
formed very soon after the intrusion and tilting of the dia- 
base. Whatever its date, the fractured and tilted condition of 
its beds, as described by Mr. Sweet, goes to demonstrate that 
the crustal movements, whether upward or downward at this 
point, had not ceased, but that on the contrary the same in- 
stability which is recorded at the St. Croix falls prevailed 
here probably at an earlier date. The pressure and crushing 
here were such as to produce a dip in the horizontal sand- 
stones of over 40°, and in other cases to obliterate their 
bedding and to cause a slaty cleavage and a micaceous grain.* 
It is very evident that a re-examination of this locality might 
throw more light on the relations existing between the traps 
and the sandstones. The lowest beds of the sandstone seem 
not to be visible. 
In reference to the southern side of Keweenaw point, to 
w^hich Chamberlin refers for further confirmatory evidence, it 
*See Irving's description of this locality, Wis. Acad. Sci., vol. ii, p. 
118, 1874. 
