272 [Uoc. 13, 



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

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

 a uuiubov of Coprolites ; also the Cj/prLt in groat abundance, and a 

 Jlodiola." 



'2. 0/1 the Lower Caeboniferoiis Rocks, or Gypsu^erous Form- 

 A ru>x of Nova Sco riA. By John AVilliam Dawson, Esq., of 

 rictou. Nova iSeotia.* 



TiiE 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 Avith 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 

 bituu\iu'ous coal. The upper portit>n of these productive coal 

 nunisures 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 hnvei", or gypsifci'Ous 

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

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

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

 ticularly observed, Avhich extends along the shores of the Gxdf of 

 St. Lawrence, from Tatmagouche to Antigouish Harbour. 



The coast section betAveeu these points cuts at acute angles 

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

 thence stretching to the west along the northern slun'o of the 

 Basin o'i IMines : the other beginning at Antigouish. and thence 

 extending westAvard to the Stewiacke ai\d Shubenacadie Rivers. 

 These two troughs are separated by a hilly range composed of 

 igneoxis rocks and of disturbed loAver-carbonifcrous and Silurian 

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

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

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

 rection of Tnu'o. 



The southern boundary of the Antigonisli trough is formed by 

 the region of Palax>zoic, metamorphic, and Plutonic rocks which 

 occupy the soutlun-n 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 Picton trough from a I'cgion belonging to the 

 coal strata which extends beyond Tatmagouche in a northerly di- 

 rection. 



The chain in question commences at the New Aatnau HiUs, and 

 extends westward through the Cobequid INIountains f to the Bay of 



* Soo tlie map of Nova Scotia. 



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

 ridge separating the coal-formation of the north side of the liasia of JNIines from 

 that of Cumborhvnd county. Mr. I^igan tirst noticed the existence of a trough 

 of carboniferous strata between Autisranish and Windsor. 



