618 MR. E. GILPIT^ ON THE &EOLOGY OF 



whence it stretches in a broad band for several miles, and its former 

 further extent is marked by isolated patches as far as Cape Porcupine, 

 on the Nova Scotian side of the Strait of Canso. The Malagawatch 

 hills are flanked by a narrovr fringe of the same series, known as 

 the Marble Mountain. It is most typically developed on the Bois- 

 dale and Coxheath hills, where it extends, in a narrow and inter- 

 rupted band, from Escasonie, on East Bay, to St. Andrew's Channel. 

 The following section from the last-named district will serve as^ 

 an index to its general character in the localities alluded to : — 



ft. 



Compact granitoid felsite of many colours 74 



Grrey and greenish friable gneiss 23 



Black and amber-coloured vitreous quartzite 115 



White and grey syenite 140 



Massive white vitreous quartzite 400 



Bluish granitoid rock 3 



Colourless laminated quartzite and red syenite 68 



Greenish finely crystalline hornblende rock 141 



Red syenite 8 



White and bluish crystalline limestone 13 



Eed syenite 8 



Greenish-grey granitoid felsite 29' 



White and bluish limestone and dolomite 8 



Eed syenite, felsite, and porphyry 7 



Limestone, bluish and saccharoidal 16 



Eed syenite 2 



White limestone and dolomite , 378 



Greenish fine-grained felsite , 37 



Greenish pyritous granite and felsite 112 



Granitoid rock 18 



Eed syenite 37 



Granire, quartzite, and bluish felsite 473 



White, bluish, and grey quartz, bluish granite, and red syenite . 3794 



The above, with some concealed intervals, make up a thickness 

 of 6602 feet. 



These strata resemble in many points the Limestone series over- 

 lying the syenitic and felsitic group of JSTewfoundland and New 

 Brunswick, and form the principal argument in favour of referring 

 both series to the Laurentian. Mineralogically there is also a 

 resemblance, for in Cape Breton, asbestos, mica, plumbago, and 

 bedded iron-ores are frequently met among the limestone series, and 

 the discovery of apatite would render the comparison with the 

 Quebec Laurentian limestone complete. 



Lower Silurian. 



The area of this formation is limited. Its principal exposure ex- 

 tends along the southern side of the Mira Eiver for about 30 miles,, 

 and has an average width of about 7 miles. A narrow, irregular 

 band stretches from Escasonie, on East Bay, nearly to the mouth of 

 the St. George's River, its width, however, never exceeds one mile. 

 A small patch is also exposed at Shenacadie, on the Little Bras 

 d'Or Lake. 



The thickness of these measures has not been determined, as they 



