1895. ] NEW YORK ACADEMY OF SCIENCES. 193 
this group; although the sections examined by the present 
writer have so far failed to show any distinctly non-voleanic 
elastics. The Coldbrook is exposed over a considerable area 
northeast and east of the city, making up the greater part of the 
pre-Cambrian hills in that direction, where its best exposures 
lie. To the west it is of less importance. 
2. Coastal (Div. 4). Overlying the Coldbrook is another 
series of rocks, more altered in its typical exposures than the 
lower group. Its lower part * is made up of volcanic rocks en- 
tirely similar to those of the Coldbrook, from which the writer 
has not been able to distinguish it. The upper part, however, is 
composed chiefly of sedimentaries, with some volcanics inter- 
bedded. The prevailing schistose structure of most of the rocks 
of this group in the area examined renders it very difficult to 
determine their nature without the aid of a thin section in each 
individual case; hence the proportion of volcanic rock is not 
very well known. It is often difficult, indeed, even with a thin 
section, to say whether a rock of this kind is altered felsite, or 
ash, or voleanic debris recomposed by water and approximating 
normal sediments. 
3. Kingston (Div. 5). This is a more altered series than either 
of the other two, and occupies a strip of land some five miles 
wide, bounded on either side by a fault line,t and not less than 
70 miles in length. Its rocks embrace recognizable surface vol- 
canics, porphyritic lavas and felsitic ash rocks, and also altered 
types, basic and acid schists, some of which were certainly of 
voleanic origin, and quite probably all. The relations of the 
Kingston to. the other pre-Cambrian rocks are very uncertain: 
Dr. Bailey Says: 
“The same uncertainty rests upon the age of the eesti 
Kingston group of southern New Brunswick, and which in its 
western extension becomes in part at least continuous with that 
to which Prof. Shaler assigns the name of ‘the Campobello 
Series.’ By that author..... they are regarded as being Lower 
Cambrian, but as beds of very similar character occur within a 
very short distance of the known Cambrian of St. John, and yet 
bear very little resemblance to it, this supposition seems un- 
tenable. As they are certainly older than the Silurian, and in 
all probability not Cambrian, they must be regarded as _ pre- 
Cambrian, the view adoptedin the Survey Reports, or as Cam- 
bro-Silurian.’’} 
* As defined by Prof. Bailey in the Report for 1877-8. 
+G. F. Matthew, Bull. Nat. Hist. Soc., N. B. XII., 46. 
t Trans. Roy. Soc. Can. 1889, Sec. 4, p. 8. 
TRANSACTIONS N. Y. ACAD. ScI., Vol. XIV., Sig. 13, May 28, 1895. 
