12 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
I of the St. John Group make up a formation largely of gray 
and dark gray clay shales (the Acadian) which would have been 
deposited in shallow sheltered bays among the volcanic islands — 
active volcanoes in earlier times but now with their fires extinct. 
The opening up of marine passages to the northern seas 
allowed the ingress from that quarter of strong currents that 
spread fine sands over the submerged surface and produced the 
formation known as Division II (Johannan). The sands of this 
division may have been the worked-over sands of theMaguma series 
of the earlier Huronian time, which spread all along the south- 
eastern side of the Acadian peninsula, then probably an island. 
A further depression of the bottom would carry it beneath and 
free of the range of the strong northern currents into the deeper 
and more sluggish ocean waters, and would allow of the deposi- 
tion of the fine dark mud of Division III (Bretonian), the highest 
formation of the Cambrian terrane, which is partly Ordovician. 
This was the condition of things along the northern border 
of the Acadian (or Nova Scotian) peninsula, but in the northern 
part of New Brunswick conditions were different and the Cam- 
brian age is represented by a formation of quartzites on sandy 
deposits, capped by Lower Ordovician mud rocks that are found 
on the Beccaguimic River and extend thence northeastward 
and southwestward. 
Synopsis . — To sum up the history of this geological system, 
we find it to have been ushered in by the bursting forth of 
volcanoes over various parts of the area north and northwest 
of the district occupied by the great Huronian, or gold-bearing 
series, of Nova Scotia, and that where these volcanoes appeared 
the earth’s crust was above the sea. Next followed the sinking 
of the volcanic deposits beneath the sea, and the invasion of 
the bays thus formed by a succession of Cambrian faunas termi- 
nating in that of Paradoxides. This sea was then opened to 
the incursion of cold currents from the north and east, and the 
Syrtensian or Ocean-shoal phase was inaugurated, with its com- 
paratively barren sands. Finally the exclusion of these strong 
currents and the deepening of the sea afforded a sheltered area 
of the sea bottom where the Parabolina, Peltura, Dictyonema 
and Tetragraptus faunas in succession held sway. 
