DISTRICT OF INVERNESS AND VICTORIA. 401 



particular part of the geological series, still named in England the 

 Oolitic formation, but it has been found in rocks of very different ages. 

 Examples of it occur in the limestones of Windsor and Pictou ; but 

 this of Mabou is much more perfect. Its little rounded grains are 

 nearly quite uniform in size, smooth and black, and cemented together 

 by gray calcareous matter. 



Near the mouth of Mabou River there is an enormous bed of gypsum, 

 which was being quarried when I last visited it for the purpose of 

 making road-embankments, this rock being the only available material 

 at band. Enormous plaster-pits have been excavated in the outcrop 

 of this great gypseous mass. One of them forms a circular grassy 

 amphitheatre, capable of containing hundreds of persons, and I was 

 informed that there is a spring of water in its centre. 



Immediately to the northward of Mabou River the lower conglo- 

 merates crop out from under the limestones and gypsum, and rise on 

 the flanks of Cape Mabou, a lofty headland, the nucleus of which is 

 syenite, of greater antiquity than the Carboniferous system, and which 

 is connected with an isolated chain of igneous and metamorphic hills 

 extending for some distance to the northward. 



At Margarie, the Coal formation again appears, with its character- 

 istic fossil plants ; but it occupies only a very limited area, and the 

 whole of the remainder of this district seems to consist of beds of the 

 Lower Carboniferous series. Mr Poole, of Glace Bay, infonns me that 

 he has received from Margarie specimens of coal somewhat resembling 

 cannel, and aflfoi'ding 41*10 per cent, of volatile combustible matter; 

 but I have no information as to its quantity, or whether it was ob- 

 tained from the Coal formation or the Lower Carboniferous series. 

 The Coal formation rocks of Poi't Hood and Margarie are evidently 

 only the margin of a coal-field extending under the sea, and perhaps 

 as far as its appearance above the sea-level is concerned, in great part 

 swept away by the waves. This coast is now rapidly wasting, in con- 

 sequence of its exposure to the prevailing westerly winds blowing 

 across the whole width of the Gulf of St Lawrence ; and its rivers 

 and harbours are from this cause choked with shifting sands. Owing 

 to this waste of the coast, a sand-beach which connected Port Hood 

 Island with the mainland has been swept away, and a safe harbour 

 has thus been converted into an open roadstead, exposed to tlie nor- 

 therly winds and encumbered with shoals. This will prove a serious 

 drawback to any attempt to work the coal-beds of this locality. 



The Lower Carboniferous limestone and gypsum appear at Chcti- 

 camp, in a number of places on Margarie River, and at Ainslie Lake, 

 which is a fine sheet of water, more than ten miles in length, and the 



