Common RocJcs of the British Provinces. 201 



Bird's-eye, and Black River Limestones, all included in the next band. 4th. 

 The Trenton Limestone which constitutes the surface where the boulders are 

 represented. 5Lh. The Utica Slate indicated by the black patches at figures 

 2 and 3. At the point 0, the Ottawa has worn out a deep channel down to 

 the Potsdam Sandstone. Between the cavity of the stream and the hills, 

 there is usually a bed of drifted materials, composed of sand, clay, or gravel, 

 with boulders. Similar beds are generally seen on both shores, and in fact, 

 spread over the whole country. 



At the City of Ottawa the channel of the river is wholly excavated in 

 the Trenton Limestone, which occupies both shores and constitutes the cliffe 

 and islands at the Chaudiere Falls. At the Chatts, on the other hand, the 

 Laurentine rocks cross the river from the north towards the south, and are 

 seen on both banks of the stream to a point a short distance above the mouth 

 of the Madawaska when the Trenton Limestone is again seen occupying the 

 south shore at different points for some distance above Sand Point. From 

 the Bonnechere to the upper extremity of the Calumet Island, the Laurentian. 

 rocks form the banks and obstructions of the river. 



It appears probable that the range of hills that may be seen running 

 along or near the north shores of the St. Lawrence, from its mouth to above 

 Quebec, and thence still further west along the north side of the Ottawa is 

 to be considered the shore of an ancient ocean. A person perched upon the 

 summit of one of those hills at the point 1, in the above figure for instance,, 

 and looking south towards 2 and 3, may survey a vast tract of level country 

 situated several hundred feet lower than the rocky pinnacle on which he may 

 be standing. From such a position, he would be looking over the wide flat 

 valley of an ancient ocean, whose waters long since withdrawn, have left as: 

 mementos of their former presence — the beds of Silurian rocks composed 

 principally of the remains of the myriads of creatures that once enjoyed life 

 in that sea. Were the water to be withdrawn from the Atlantic, those living 

 upon the shore might descend into the deserted cavity, people the newly 

 desiccated country, and cover it over with smiling fields and thriving towns. 

 They might dig up from the soil the remains of the various marine animals, 

 study their structure, and exhibit them in museums for the gratification of 

 the curious. The Natural History of the Atlantic could then be ascertained 

 long after the ocean, and all its tenants had ceased to exist. And, it is thus, 

 that the greater number of the inhabitants of Canada are living in the bed 

 of an ocean, of which the fossils accumulating in our museums are the organic 

 remains. 



The next figure is a section across Western Canada from the County of 



Victoria, passing westerly through the Counties of Ontario, York, Peel, 



Wellington, Waterloo, Oxford, Middlesex, Laml/f.on,. and into the State of 



Michigan. It is scarcely necessary to observ'.' that the section is only a 



rough outline exhibiting the geological structiiie of the country in a very 



general way. At the point A in the County of Victoria, are seen the 



Laurentian rocks. They constitute the bottom in the direction indicated hy 

 the letters L L L westerly. Upon them repose 1 and 2 the Lower 

 Silurian, 3 the Upper Silurian, and 4 the X)eYomem formations, whicli 



