Wadsworth.] 
276 
[October 19, 
same induration of the argillite, the same modification of the 
granite, and the same welding of the two rocks, together with the 
same irregular line of junction, was observed as before (Nos. 1340- 
1345). We thus find that on the eastern and western sides of 
the argillite, the relations to it of the granite are identical. 
Professor Niles andMr. Crosby (Contributions, pp. 37, 38) have 
observed the contact of the Quincy granite with argillite and 
other rocks elsewhere, as has the present writer, but in these cases 
the age of the argillite and other rocks, while supposed to be 
Primordial, were not known to be so. This then gives us the 
first definite information, of which I am aware, of the age of 
the Quincy granite and its relations to the Paradoxides slate. 
Taking then the generally recognized canon of geological law, 
the Quincy granite is an eruptive rock of late Primordial or more 
recent age. I state the above thus plainly, since in recent 
years different views have been advocated in the publications of 
this Society. 
It may be interesting to note in passing, that the Quincy granite 
in the vicinity of the Paradoxides quarry was taken for a sand- 
stone or quartzite by Prof. N. S. Shaler, who thought that the 
commonly quarried Quincy granite was a metamorphosed sedi- 
mentary rock, passing in its extension into these supposed quartz- 
ites, upon which the Braintree argillite lay, according to him, 
conformably. The granite east of the argillite was thought by him 
to be the same quartzite, as the quartzite (granite) on the western 
side of the argillite, but brought up by a fault. It is to be noticed 
that no fault line was found by me on either side, but that single 
pieces were obtained showing the complete welding of the granite 
to the argillite. (Proc. Bost. Soc. Nat. Hist. 1869, XIII, 172- 
178). 
The Quincy granite which Professor Shaler took to be a quart- 
zite, Dr. T. Sterry Hunt declared was a felsite identical with 
that of Lynn, Marblehead, Missouri, and elsewhere, as well as 
with that forming the conglomerate bed of the Calumet and 
Hecla mine. This rock was said by him to be distinctly stratified 
and to be of Huronian age. The Quincy and other granites, sup- 
posed by him to be of the same age and origin, seen elsewhere, 
it seems he regarded as eruptive rocks cutting the felsite. Thus 
