Page:The Journal of geology (IA journalofgeology21894univers).pdf/34
(Laurentian); a felsite-petrosilex group (Lower Huronian or Coldbrook); and a schistose, chloritic micaceous group (Upper Huronian or Coastal).[1] The results of all their work on the rocks of southern New Brunswick is summarized by Bailey, Matthew and Ells, with a general geological map in three sheets.[2]
That portion of the Province of Quebec lying south and east of the St. Lawrence is called the Eastern Townships. We have already considered that portion of it composing the Gaspé peninsula. The portion lying west of Maine and north of New Hampshire and Vermont was supposed by Logan to be wholly occupied by rocks of the Quebec Group. In 1879, Dr. Selwyn divided the rocks of this zone into three groups, which he defined as lower Silurian; volcanic (probably lower Cambrian); and crystalline (probably Huronian). The lower of these divisions forms an anticlinal axis extending from Lake Memphremagog to L'Islet County, 150 miles. It contains a great variety of altered sedimentary beds, associated with "diorites, dolerites, serpentines, amygdaloids, and volcanic agglomerates," regarded by Hunt as altered sedimentaries. The second division, said to be intimately related to the last, is largely composed
"especially on the southeastern side of the axis, of altered volcanic products both intrusive and interstratified, the latter being clearly of contemporaneous origin with the associated sandstones and slates."
These rocks are designated as
"dioritic, epidotic, and serpentinous breccias and agglomerates; diorites, dolerites and amygdaloids holding copper ore; serpentines, felsites and some fine grained granitic and gneissic rocks."
They are especially developed along the contact of the last-mentioned group, of which they "may be merely the upward extension."[3] In a later paper on the Quebec Group, Dr. Selwyn considers these volcanic rocks thoroughly from the English point of view. He says: