285 



Kilometres Carbonifcrous. Above these lie limestone and 

 gypsum beds followed by a great thickness of 

 shales and reddish and grey, plant-bearing sand- 

 stones. Above these lies a thick series of black 

 shales with, in several places, coal seams. The 

 highest strata presumably belong to the Coal 

 Measures. 

 74-5 m. Point Tupper — From Point Tupper the rail- 



120 km. way trains are ferried across Canso strait to the 

 terminus of the railway on the mainland at 

 Mulgrave . The strait at this point is i ,400 yards 

 (1,280 m.) wide. 



Along the shore on the Cape Breton side of 

 the strait, the strata dip easterly at angles of 

 30° to 60°, and are well exposed over many 

 partial sections to the north and south of Point 

 Tupper. 



From the Cape Breton side of the strait, the 

 mainland is seen to rise quickly to a rolling up- 

 land. To the north however, the Pre-Cambrian 

 area of Cape Porcupine forms a detached, 

 higher mass. Nearly the whole length of the 

 mainland side of the strait is bordered by so- 

 called Devonian strata which extend from here 

 in a continuous band westward to Windsor. 

 These "Devonian" measures are of variously 

 coloured shales and sandstones with an aggregate 

 thickness of, presumably, considerably more than 

 5,000 feet (1,500 m.). The strata dip in various 

 directions at angles usually of 45° or higher; 

 they apparently are much folded. Plant- 

 bearing beds occur at various horizons and, in 

 a general way, the measures have been corre- 

 lated with the Riversdale-Union group. At 

 several places strata of the Horton series occur 

 within this area in the neighborhood of Canso 

 strait, and at several places along the shore, as 

 just south of Mulgrave, there are limited areas 

 of the Carboniferous Limestone series. 

 75-2 m. Mulgrave — After leaving Mulgrave on the 

 121-1 km. mainland side of Canso strait, the railway enters 

 the valley bounding Cape Porcupine hill on the 

 south and west. From this point may be seen 

 the rolling ridges and low rounded summits of 



