Page:The Journal of geology (IA journalofgeology21894univers).pdf/32

daloids, aphanites, etc.) occur around the head of the Bay of Chaleur and Dalhousie, as well as on the upper Upsalquitch and Elm Tree rivers. Many of these rocks are pre-Cambrian, while others cut the Silurian strata.^[1] Great sheets of contemporaneous trap are also found by Ells in the Silurian, and to a very small extent in the Devonian, along the north shore of the Bay of Chaleur. Bailey explored parts of northern and western New Brunswick, especially in Carolton, York and Victoria counties, and found porphyries, felsites and amygdaloids, intrusive in the Silurian and older formations in Canterbury, Woodstock and Kent townships, near the St. Johns river.^[2] Still later Bailey and McInnes continued similar explorations, and found signs of intense volcanic action in the Niagara limestone at Pointe aux Trembles, and a great development of acid and basic surface rocks near the Aroostook river and at Presqu'ile and Haystack mountain in Maine.^[3] The same is true near Tobique lake, farther to the northeast.

As early as 1839, Gesner describes the volcanic rocks along the Bay of Fundy, in southern New Brunswick, as belonging to several distinct horizons.^[4] In 1865, Bailey, Matthew and Hartt distinguished two groups mainly of volcanic origin, to one of which, the "Coldbrook," they assigned a Huronian, and to the other, the "Bloomsbury," a Devonian age.^[5] In 1872, Bailey and Matthew, after a season's field-work with Dr. T. Sterry Hunt, united the Coldbrook and Bloomsbury groups on purely lithological grounds, and for the same reason joined with them two other volcanic series—the Coastal and Kingston groups—exposed at other localities in southern New Brunswick.^[6] The petrographical characters of these rocks were those regarded by Hunt as sufficient demonstration of Huronian age. The acceptance of this fallacious principle exercised a distinctly