26 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



above the Main Coal at Sydney, he has found the scales of dif- 

 ferent kinds of fishes, as hard and bright as enamel ; one tooth, and 

 a number of Coprolites ; also the Cypris in great abundance, and a 

 Modiola? 



2. On the Lower Carboniferous Eocks, or Gypsiferous Form- 

 ation of Nova Scotia. By John William Dawson, Esq., of 

 Pictou, Nova Scotia.* 



The coal formation of the eastern part of Nova Scotia consists of 

 a great thickness of sandstones, shales, and conglomerates, of va- 

 rious reddish and grey colours, the former being most prevalent. 

 The lower part of the series is distinguished by the presence of 

 limestones with marine shells and gypsum. Its central portion is 

 characterised by a greater prevalence of grey and dark colours, 

 and by containing an abundance of vegetable fossils and beds of 

 bituminous coal. The upper portion of these productive coal 

 measures appears to pass into a thick deposit of reddish sandstones 

 and shales, containing few fossils, either animal or vegetable. To 

 examine the structure and relations of the lower, or gypsiferous 

 part of this series, is the object of the present paper : it will, how- 

 ever, be proper in the first place to notice the general disposition 

 of the rocks of the Carboniferous system, in the region more par- 

 ticularly observed, which extends along the shores of the Gulf of 

 St. Lawrence, from Tatmagouche to Antigonish Harbour. 



The coast section between these points cuts at acute angles 

 across two great coal troughs, the one beginning at Pictou, and 

 thence stretching to the west along the northern shore of the 

 Basin of Mines ; the other beginning at Antigonish, and thence 

 extending westward to the Stewiacke and Shubenacadie Rivers. 

 These two troughs are separated by a hilly range composed of 

 igneous rocks and of disturbed lower-carboniferous and Silurian 

 strata. This range beginning at Cape St. George extends west- 

 ward to the East River of Pictou ; and beyond this it is continued 

 along the outcrops of the oldest carboniferous rocks in the di- 

 rection of Truro. 



The southern boundary of the Antigonish trough is formed by 

 the region of Palaeozoic, metamorphic, and Plutonic rocks which 

 occupy the southern side of the province. A chain of hills, similar 

 in structure to the range of Cape St. George, but of greater eleva- 

 tion, separates the Pictou trough from a region belonging to the 

 coal strata which extends beyond Tatmagouche in a northerly di- 

 rection. 



The chain in question commences at the New Annan Hills, and 

 extends westward through the Cobequid Mountains f to the Bay of 



* See the map of Nova Scotia. 

 f t Dr. Gesner, many years since, described the Cobequid chain as forming a 

 ridge separating the coal-formation of the north side of the Basin of Mines from 

 that of Cumberland county. Mr. Logan first noticed the existence of a trough 

 of carboniferous strata between Antigonish and Windsor. 



