1 6 THE JOURNAL OF GEOLOGY. 



be removed like the coats of an onion." He also speaks of 

 them as "coarsely brecciated" and "vesicular." A point of 

 some interest is Fletcher's conclusion that "both felsite and 

 syenitic strata are intimately associated as part of the same 

 group of crystalline rocks, differing, not so much in composi- 

 tion as in the degree of crystallization they have been subjected 

 to" [sic)} In greatly eroded regions we should expect to find 

 surface volcanic rocks associated with their coarser abyssal 

 ec[uivalents. 



In Nova Scotia proper the best known area of ancient vol- 

 canic rocks is in the northeastern corner of the province, near 

 Arisaig, in Antigonish county. These were considered by Sir 

 William Dawson in 1850 as "metamorphic."^ In 1864, Dr. 

 Honeyman described them as vesicular traps, amygdaloids and 

 porphyries, associated with tufa and tufaceous conglomerate. 3 

 In his first report on eastern Nova Scotia, Fletcher describes 

 variegated, vesicular and amygdaloidal "felsites" and "frag- 

 mentary felsites," like those of Coxheath and Louisburg, asso- 

 ciated with "syenite" (hornblende granite) and diorite.-* These 

 rocks are regarded as pre-Cambrian, and are particularly devel- 

 oped at Arichat, Cape Porcupine on the Straits of Canso, and in 

 the Sporting, North and Craignish mountains. In the North 

 Mountains the felsites are said to pass gradually into syenite 

 (1. c. p. 14). The gradual blending of the felsite and overlying 

 George River limestone is attributed to "common metamorph- 

 ism," rather than "to contemporaneous volcanic origin or sub- 

 sequent intrusion" (1. c. p. 17). Nevertheless, at Cape Porcu- 

 pine the felsite is regarded as possibly an igneous rock, since 

 "the apparent lines of bedding are like those of a furnace slag" 

 (1. c. p. 25). In the subsequent report of the extension of his 

 explorations southward and westward in Nova Scotia, Fletcher 

 admits the volcanic origin of the felsitic rocks of Arisaig, Doc- 



' Quoted by Gilpin: Quart. Jour. Geol. See, Vol. 42, p. 516. 



-Quart. Jour. Geol. Soc, Vol. 6, p. 347, 1850. 



3 lb., Vol. 20, p. 333, 1864. 



"* Report of the Geol. Survej' of Canada, 1879-80, F. 



