134 



(Upper Cambrian) sandstone, a group of unique concre- 

 tions is to be seen. These stand in tree-like forms, in 

 vertical position, and cross the bedding of the sandstone. 

 One of these cylinders is fully 15 feet (4-5 m.) in diameter. 

 These sandstones show some interesting bleaching effects, 

 where the red iron oxides, on being leached out of the 

 sandstone, produce white bleached spots or streaks. 



Miles and 

 Kilometres. 



ANNOTATED GUIDE. 



Leaving Kingston by automobile, the road 

 leads in a north-easterly 



o m. Kingston. direction along the west 



o km. side of Rideau canal. The 



country is flat in character, as the rocks are 

 bedded limestones of Ordovician age. After 

 4! miles (7-2 km.) of such country, the road 

 descends a steep hill which forms a cliff-like 

 margin to the old channel of Rideau river, 

 which was incised along the contact of the 

 Ordovician with the Pre-Cambrian floor. A 

 half mile (-8km.) farther on is Kingston 

 Mills. 



Here the limestone is seen in the railway 

 cutting to lie unconform- 



5 m. Kingston Mills, ably on the Pre-Cambrian. 



8 km. A basal conglomerate com- 



posed of large water-worn boulders of granite 

 and gneiss cemented in a limestone mud is 

 seen. The limestone is filled with fragments 

 of the quartz of the old floor, this being 

 the one imperishable mineral it contains. 

 Within 3 feet (-9 m.) of the actual contact, 

 the limestone becomes much cleaner, and is 

 filled with fragments of Orthoceras and En- 

 doceras well preserved. 



The granite in the railway cutting shows 

 perfectly fresh exposures, and some of the 

 finest possible examples of jointing in three 

 directions are to be seen. At the east end of 

 the rock cut are the Kingston Mills locks on 

 the Rideau canal, where boats are lowered 



