1880 .] 
91 
[Wadsworth. 
distinct periods of art and also distinct methods of manifest- 
ation. 
Prof. E. S. Morse read a native translation of a sketch of the 
Ainos by a Japanese physician, containing many interesting obser- 
vations on their physique, habits, and arts. 
General Meeting. November IT, 1880. 
Vice-President, Mr. F. W. Putnam, in the chair. Forty-eight 
persons present. 
The following paper was read : 
ON THE FILLING OF AMYGDALOIDAL CAVITIES AND 
VEINS IN THE KEWEENAW POINT DISTRICT OF LAKE 
SUPERIOR. A REPLY TO PROF. JAMES D. DANA. 
BY M. E. WADSWORTH, PH.D. 
Since Professor Dana hi a recent notice (Am. Journ. Sci., 1880, 
(3), XX, 330-332) of a paper of mine (Notes on the Geology of 
the Iron and Copper Districts of Lake Superior, Bull. Hus. Comp. 
Zoology, 1880, VII, [Geol. Series I] 1-157) has presented his 
views regarding the disposition of mineral matter in amygdules 
and veins in the copper district mentioned above, it seems fitting 
that some of the reasons why his hypothesis can not be adopted 
by me should be given here. Especially is this the case since the 
subject was only briefly touched upon in my paper, and also 
because the great weight of his authority leads, in many cases, to 
the adoption of his views without examination. It is further to 
be understood that the writer has a personal knowledge of the 
facts which he cites concerning the region under discussion, while 
Professor Dana’s statements have to derive their foundations 
from the observations of others, as he was never in the district in 
question, so far as the writer can learn. 
In a discussion of this kind one rarely convinces one’s oppo- 
nent, yet such discussion conduces to the advancement of the 
science, by calling the attention of others to the subject, thus 
leading to further observations and investigations. 
