1895. ] NEW YORK ACADEMY OF SCIENCES. 209 
THE KINGSTON GROUP. 
This group presents a series of volcanic rocks parallel to 
those of the Coldbrook, but far more altered. The acid mem- 
bers are strongly sheared, often unrecognizable as volcanic, and 
with a great development of secondary micas, making a quartz- 
ose or feldspathic mica-schist. Some of these schists retain 
their porphyritic crystals with clear cut edges and compara- 
tively little altered, though the ground mass is all recrystallized. 
Ash rocks, now changed to flinty felsites, are sometimes still re- 
eognizable, but no doubt most of them are too much metamor- 
phosed to be determined. 
The basic rocks of the series are even more changed. Though 
mostly less cleaved, they are coarsely crystalline hornblende 
schists, with no traces of their original structure visible under 
the microscope. Kemnants of the porphyritic feldspars some- 
times still appear as white spots scattered through the dark 
schist, but their original form is lost. 
These remarks apply to the New River exposures, the only 
ones examined by the writer. A modification of them might 
be necessary on study of other areas of Kingston rocks which 
show certainly a greater variation in the amount of metamor- 
phism than is seen at New River. 
COMPARISONS. 
In their original character and degree of preservation the 
New Brunswick effusives may best be compared with those of 
South Mountain. The volcanics of the Boston Basin, as far as 
the writer has seen them, seem to be more dense and massive, 
less shattered and epidotized and more crystalline than ours. 
In field characters there is a considerable resemblance to the 
volcanic series along the Maine coast, at Eastport and Mount 
Desert; but I have seen no petrographic descriptions of these. 
The rocks of the Coldbrook group seem to be much less 
sheared than almost all of the South Mountain rocks, to which 
our Coastal volcanics show a closer resemblance in this respect. 
The Coldbrook felsites are also of finer grain, their recrystalli- 
zation not haying proceeded quite as far. The characteristic 
structures of volcanic rocks, as has already been detailed, they 
possess in great perfection, the only structure of which I have 
not seen satisfactory examples being chain spherulites. 
It is worthy of note that all these ‘ancient volcanic rocks,” 
as Dr. Williams happily termed them, lie unconformably under- 
TRANSACTIONS N. Y, ACAD. Scr., Vol. XIV., Sig. 14, June 18, 1895. 
