NOVA SCOTIA. 377 



In commenting upon Mr. Robb's work, Mr. Selwyn remarks : — 

 " The exaniinatious recently made by Mr. Robb at Kelly Cove on the Great 

 Bras D'Or Lake show that a similar series of crystalline rocks, — magnesian 

 limesttmes, serpentine, &c., — occur there between the Carboniferous series 

 and the freat mass of syenite, which bus been supposed to be of Laurentian 

 a^e ; but which will, I think, more probably prove to be an intrasive ma^s 

 nearly corresponding in age with the gre;it central granitic axis of Nova Scotia, 

 which is undoubtedly pre-Carboniferous and post-Devonian." (/. c, p. 9.) 



This is certainly a striking change in Mr. Selwyn's opinion since 

 1871. The evidence, however, is strongly in favor of his later views. 

 Mr. Hugh Fletcher, from more extended labors in Cape Breton, ren- 

 dered it quite evident that in some localities the syenites and felsites 

 are older than some lower Silurian rocks, hence probably Azoic. He 

 relies on lamination solely to prove the sedimentary origin of the rocks 

 in question, and on almost every page shows by his work that he has 

 no knowledge of the characters of eruptive rocks, or of the methods of 

 proving in the field whether the rocks in question are or are not erup- 

 tive. His statements concerning their origin are therefore valueless. 



The St. George limestone, which he thinks may possibly be Huro- 

 niau, — although he has classed it as Laurentian, — is said to contain 

 pebbles apparently derived from the syenites and felsites. (Repoiiis of 

 Progress, 1875-76, pp. 371-388; 1876-77, pp. 405-428; 1877-78, 

 pp. 3-10, F.) 



The age of the limestone was not determined any farther than that it 

 was shown to be older than the Cai-boniferous ; it was simply assumed 

 that it was Azoic. Concerning the Hurouian in Xova Scotia, Principal 

 J. W. Dawson remarks : — 



" There is no good evidence that the Cobequid series and its equivalents in 

 Pictou and elsewhere are older than the Lower Silurian. There seems, how- 

 ever, good reason to class as Huronian, or at least as liower Cambrian, the 

 rocks of the Boisdale Hills in Cape Breton, which Mr. Fletcher finds to under- 

 lie the fossihferous Cambrian of that region, and which are more quartzose 

 and micaceous than the rocks of the Cobequid series. It is not impossible 

 that rocks of this age may also occur in the ^^cinity of the Cambrian beds 

 found at Mire. We may also conjecturally class as Huronian the chloritic 

 rocks of Yarmouth." (Supplement to Acadian Geology, 1878, p. 88.) 



In the same work Dr. Dawson also states regarding the Lauren- 

 tian : — 



" Dr. Honeyman and Prof. Hind have suggested the Laurentian age of 

 certain rocks as Arisaig, in the Cobequids, and associated with the coast Meta- 



