336 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 21, 



the Cove, are thick beds of grey conglomerate, in a vertical position. 

 These beds form the base of the carboniferous system in this district ; 

 and, at a short distance inland, they have been invaded by trap and 

 other igneous rocks, belonging to a great line of igneous disturbance 

 extending to the north-eastward. The conglomerates near M'^Millan's 

 Point have been thrown up along an anticlinal line connecting the 

 igneous range last mentioned with that of Cape Porcupine, on whose 

 flanks the same conglomerates appear. The valley now occupied by 

 the Strait is in great part due to the want of continuity of the igneous 

 masses at this point ; though the distribution of the surface detritus 

 shows that it has been subsequently deepened by dilu"\ial waves or 

 currents from the northward. 



(2.) Between INFMillan's Point and Plaister Cove, the shore is 

 occupied by black and grey shales and very hard sandstones, in fre- 

 quent alternations. The sandstones have been much altered by heat, 

 and are traversed by veins of white carbonate of lime, sometimes mixed 

 with sulphate of barytes. At the point immediately north of Plaister 

 Cove, these beds dip at a high angle to the south-eastward. 



(3.) Overlying these beds is a bed of limestone about 30 feet in 

 thickness ; it is of a dark colour, laminated and subcrystalline ; 

 its laminae are in some parts corrugated and slightly attached to each 

 other, and in other places flat and firmly coherent ; it is traversed 

 by numerous strings of white calcareous spar, containing a httle car- 

 bonate of iron and small crystals o^ blue fluor spar, a mineral rare in 

 Nova Scotia, and which I have found only in the lower carboniferous 

 limestones. The limestone supports a few layers of greenish marl 

 and gypsum, which appear in a small depression on the north side of 

 the Cove ; but beyond this depression the limestone reappears with 

 a northerly dip. It is then bent into several small folds, and ulti- 

 mately resumes its high dip to the south-east. I found no fossils in 

 this limestone, except at its junction with the overlying marl, where 

 there is a thin bed of black compact limestone containing a few in- 

 distinct specimens of a small species of Terebratula. In appearance 

 and structure this limestone is very similar to the laminated limestones 

 which underlie the gypsiferous deposits of Antigonish and the Shu- 

 benacadie. 



(4.) This bed is succeeded by greenish marl, traversed by veins ot 

 red foliated and white fibrous gypsum, and containing a few layers of 

 the same mineral in a granular form ; it also contains a few veins of 

 cry'stalline carbonate of hme. In its lower part it has a brecciated 

 structure, as if the layers had been partially consolidated and then 

 broken up. Near its junction with the limestone it contains romided 

 masses of a peculiar cellular limestone, coloured black by coaly matter ; 

 and higher in the bed there are nodules of yellow ferruginous lime- 

 stone with a few fragments of shells. The greenish colour of the 

 marl seems to be caused by the presence of a minute quantity of sul- 

 phuret of iron. When a portion of the marl is heated, the sulphiu'et 

 is decomposed and the colour is changed to light red. 



(5.) On this marl rests a great bed of gypsum, whose thickness I 

 estimated at 50 yards. Where the marl succeeds to the limestone, the 



