ON THE GEOLOGY OF CAPE BRETOIf ISLAND. 515 



42. The Geology of Cape Breton Island, N'ota Scotia. By Edwin 

 Gilpin, Esq., Jun., A.M., F.R.S.C, Inspector H.M.'s Mines. 

 (Read June 23, 1886.) 



In the following notes the writer has tried to give a brief account 

 of the geology of this island from notes of his professional work as 

 Inspector of Mines and from other available sources. Mr. R. 

 Brown, of the Sydney mines, lived for many years on the island 

 when it was, geologically speaking, an unexplored region. The 

 Transactions of the Society contain several valuable papers of his, 

 giving many details of the Carboniferous system. Sir J. W. Dawson, 

 in his 'Acadian Geology,' indicated the outlines of the principal 

 geological divisions, and devoted much attention to the Carboni- 

 ferous flora. During the past fifteen years Mr. H. Fletcher, of the 

 Canadian Geological Survey, has explored and mapped the island, 

 and the map accompanying these notes has been reduced from the 

 large scale-plans accompanying his annual reports, from which I 

 have taken several sections. Valuable reports were made by Pro- 

 fessor Lesley, Mr. Lyman, and others on several districts considered 

 of economic importance ; but the list of writers is a scanty one. 



The geology of Cape Breton is notable on account of the develop- 

 ment of two great rock series — the Carboniferous and the Pre- 

 Cambrian. There are no measures known later than the upper 

 portion of the productive Coal-Measures, and between the basal 

 conglomerate of this period and the Pre-Cambrian there intervene 

 only a few areas referred to the Devonian and the Lower Silurian. 



The following formations have been recognized in Cape Breton by 

 the officers of the Geological Survey: — 



Pre-Cambrian (Laurentian) : 



J 1 -]. r The Felsite series, 



° \ The Crystalline Limestone series. 

 Lower Silurian. 

 Devonian. 

 Carboniferous : 



( Middle Coal-formation, 

 j Millstone Grit, 

 Including \ f Gypsif erous series, 

 I \ Limestones, &c. 

 \^ Lower Coal -formation. 



Pre-Cambeian, Felsite Series. 



The exact age of the strata included under this term has been a 

 matter of doubt, and many have called them Laurentian. Their 

 isolated position has precluded the chance of following them into 

 regions where convincing stratigraphical relations can be found. 

 The auriferous rocks of the Atlantic coast of JSTova Scotia do not 

 extend into the island, but they supply an important link in the 

 geological sequence. They are considered to be Lower Cambrian, 

 the equivalents of the Longmynd series, and appear with the 

 Acadian series of St. John, New Brunswick, to belong to the gap 



