THE DISTRIBUTION OF ANCIENT VOLCANIC ROCKS. I 5 



materials, but thus far no petrographer has attempted to study 

 systematically either the field or microscopical relations of any 

 area of these interesting rocks. A very broad and interesting 

 field is thus seen to be awaiting investigation in Newfoundland, 

 Gaspe, New Brunswick, Nova Scotia and the Eastern Town- 

 ships. 



Professor J. B. Jukes, in his "Geology of Newfoundland," 

 describes old lava flows and accompanying pyroclastic deposits 

 as very abundant, especially on the peninsula of Avalon, which 

 forms the eastern part of the island.^ His observations are con- 

 firmed by the later reports of Murray and Howley, who agree 

 that the western part of this peninsula was the scene of extraor- 

 dinary volcanic activity in very early times. ^ 



In his three reports on the eastern portion of Cape Breton, 

 Fletcher describes the Ste. Anne, Boisdale, Coxheath, East Bay 

 and Mira Hills, as composed largely of ancient (pre-Cambrian) 

 volcanic rocks, among which felsites of all colors, felsite-por- 

 phyries, felsite breccias and amygdaloids abound. 3 Similar 

 rocks appear also to extend up into, and to form an important 

 part of the Cambrian, Silurian and Devonian formations. In a 

 later report on the northern part of Cape Breton, Fletcher ■♦ finds 

 that the greater part of the northern peninsula is also composed 

 of "felsites," but the petrographical distinctions of both Fletcher 

 and Gilpin ^ are so indefinite that a variety of coarsely crystal- 

 line rocks seem to be embraced in this general designation. In 

 describing the Mira "felsites," Fletcher mentions those of Blue 

 Mountain and Gull Cape, near Louisburg, as being "globular," 

 or "concretionary," (coarsely spherulitic?) often presenting 

 "single or united spheroids, the concentric layers of which may 



' Excursions in and about Newfoundland in 1839 and 1840, 2 vols., 1843. Geol- 

 ogy, Vol. 2, pp. 245-341. 



^Reports of the Geological Survey of Newfoundland for 1868-1881. 



^Reports of the Geol. Survey of Canada, 1875-76, pp. 369-418; ib., 1876-77, 

 pp. 402-456; ib. 1877-78, pp. 1-32, F. 



■tlb., 1882-83-84, pp. 1-98 H. 



5 Quart. Jour. Geol. Soc, Vol. 42, p. 515, 1886. 



