222 DALE NM OUORINALE, OF, GROLO GNA 
it is in contact. This contact is not sharp in places, as the gneisses 
usually seem to have been infiltrated by basic feldspar material from the 
anorthosite, causing a gradual passage from one to the other. At one 
place in division 11 appears.a band of highly crystalline limestone. 
At many places the Trenton limestone is found directly in contact 
with the Archean rocks. ‘The surface of the Archean rocks on which 
these newer beds were laid down had a rounded undulatory form, 
closely resembling the present exposed surface. The gneisses and the 
limestone present fresh, undecomposed surfaces. At various places 
between the Trenton limestone and the Archean is a thin layer of cal- 
careous sandrock, resting in the hollows of the Archean surface, which 
holds Trenton fossils. In one place in the limestone is found a bowlder 
of gneiss six feet long, four feet wide and four feet thick, which is 
supposed to have been dropped by floating ice. 
Mathew, W. D.’ describes the pre-Cambrian area near St. John, 
New Brunswick. The earliest series, or Laurentian, consists chiefly 
of granitic and gneissoid rocks, limestones and quartzite, the two latter 
being confined to the upper beds. ‘The strata lie steeply inclined in a 
succession of ridges and folds striking in a general northeast and 
southwest direction. Overlying this more crystalline series, generally 
at a lower dip, are fine-grained flinty rocks, interbedded with various 
schists, porphyries, ash-rocks and sandstones, and with great masses 
and dikes of trap. ‘These have been called Huronian. 
The old part of the Laurentian consists of gneisses proper, accom- 
panied by hornblende-schists and mica-schists, which in thin section 
show no trace of igneous origin, and of limestone and quartzite. 
Associated with the less crystalline limestones are beds of fine-grained 
black rock, which has generally been called argillite. Much of the 
Lower Laurentian series consists of granite, diorite and gabbro, which 
are igneous rocks. The granite intrudes both the gabbro and the 
sedimentary series as is shown by contact effects and by veins 
and pegmatite masses adjacent to the granite in the sedimentary 
series. As to the age of this intrusion, it may be as late as 
Devonian, but as the granite is cut by innumerable dikes which also 
cut the Huronian and the Paleozoic, it is very likely that the intrusion 
is pre-Huronian. The great unconformity in the district is between the 
Laurentian and Huronian, not between the Huronian and Cambrian. 
«The Intrusive Rocks near St. John, New Brunswick, by W. D. MATHEW. Trans. 
N. Y. Acad. Sci., Vol. XIII., pp. 185-203, 1894. 
