SUMMARY OF CURRENT PRE-CAMBRIAN NORTH 
AMERICAN LITERATURE. 
MATTHEW* gives the following pre-Cambrian succession near St. John, 
Ne 18368 
A.—Laurentian. 
1. Portland group, including Division 2, with probably parts of Division 1 
in other localities than St. John. 
2. Intrusive granite and quartz-diorite; perhaps later than the position 
here assigned to it. 
B.—Huronian. 
3. Coldbrook group or Div. 3, of volcanic rocks. 
4. Coastal group or Div. 4, of volcanic and sedimentary rocks, in its upper 
part probably equivalent to the next group. 
5. Etcheminian or Basal Series, of sedimentary rocks, underlying the St. 
John group. 
6. Kingston group or Div. 5, of metamorphosed volcanics. Of very 
uncertian relations ; may be post-Cambrian. 
The Huronian in southern New Brunswick is in large part made up of sur- 
face volcanic rocks. The lower part or Coldbrook group is almost exclusively 
volcanic; the upper part or Etcheminian is clastic, while the intermediate 
Coastal contains both volcanic and sedimentary members. The effusive rocks 
include lavas, breccias, and tuffs, and with them may be placed a holocrystal- 
line soda-granite which is probably either an intrusion or a very thick surface 
flow. 
The Etcheminian series rests unconformably upon the Coldbrook series and 
unconformably below the St. John group, which is for this district placed at 
the base of the Cambrian. The igneous rocks comprise effusives, including 
quartz-porphyry, felsite-porphyry, diabase, and feldspar-porphyrites, and dike 
rocks, which include diorite-porphyrite, diabase, and augite porphyrite. Each 
of these is described in detail. : 
Bailey? gives a preliminary report upon southwestern Nova Scotia. The 
oldest rocks here found are those of the Cambrian system, in which there is 
the following succession from the base upward: 
t The Effusive and Duke Rocks near St. John, N. B., by W. D. MATTHEW, Trans. 
N. Y. Acad. Sci., Vol. XIV., 1895, pp. 187-217, Plates XII.-XVII., Figs. A. B. 
2 Preliminary Report on Geological Investigations in Southwestern Nova Scotia, 
362 
