NORTH SYDNEY AND SYDNEY MINES, C. B. — DeWOLFE. 295 



but very variable amounts of lime. The shale, digested in HCl. 

 leaves an insoluble residue of clay amounting to about 75^, 

 The sandstone contains from 75^ to 90^ silica. The marl leaves 

 a much smaller residue than the shale. 



Inland ohservations. — These rocks are all exposed in a 

 railway cutting immediately south of Limestone brook. They 

 lie conformably, showing good contacts between the sandstones 

 and calcareous shales, and dip 30° ]^. The sandstone here 

 breaks into large flags suitable for building purposes. Ripple 

 marks exposed on the under surface, wherever the underlying 

 shale has fallen away, show wind from the south. At another 

 horizon, a mile away, markings show an east wind. 



The direction of dip here is important, as well as the 

 amount, which is greater than in the Coal Measures to the east. 

 The strata are under the immediate influence of the granitic 

 core of the Boisdale hills to the southwest. 



From this cut doAvnward along Limestone brook, the ground 

 is low and swampy, and gives no outcrops. On Fletcher's recent 

 map ( :00) this brook is given as the boundary line between the 

 lower series and the Millstone Grit, except for about half a 

 mile where limestone is given on both sides. Finding no ex- 

 posures, I am unable to verify his conclusions. At the mouth 

 of the brook, however, the contact is at least two hundred feet 

 southwest of its stated position, for grit is exposed throughout 

 that distance. The map also indicates fossils near the bank of 

 the brook, nearly a mile from its source. I was unable to find 

 there any exposures of bedrock; but a large slab of drift sand- 

 stone contains some fossils. 



Section along shore. — For about a mile eastward from the 

 mouth of Leitch's creek, the banks are low and give no cliffs; 

 but the glacial debris is shallow, and the rock frequently out- 

 crops on the beach. These exposures show a calcareous sand- 

 stone with a laminated shaly structure, the rock crumbling 



