1864.] GRANT ON THE GEOLOGY OF THE OTTAWA. 423 



interstratified here and there with a few beds of dark lime- 

 stone. It is found in considerable quantity near this city, and is 

 seen cropping out directly across the Eideau Bridge, near the 

 General Protestant Hospital. In the Townships of Collingwood 

 and ^Yhitby this shale is sufficiently bituminous to produce 

 mineral oil in considerable quantity. 



The Drift or Boulder Formation, of which we have ample 

 evidence in this locality, comes under the Post-pliocene or Post- 

 tertiary period. The clay, sand, and gravel of the valleys of the 

 Ottawa and St. Lawrence, containing sea-shells or the skeletons 

 of marine fish, are also referred to it. Owing to the manner in 

 which drift is supposed to have been formed (that is, transported 

 by ancient glaciers), it is termed Glacial Drift. " The greatest 

 development and extension of these glaciers is said to have been 

 during the interval between the close of the Cainozoic period and 

 the commencement of the existing epoe-h, properly so called." Ifc 

 forms the surface of country over a great part of the triangular- 

 area included by the St. Lawrence and Ottawa rivers. Stratified- 

 clays and sand fill up depressions of great extent over this surface? 

 and erratic boulders of great size are to be observed, in localities 

 the most unexpected. A granitic boulder of considerable magni- 

 tude is to be seen just above, and to the right of the Suspension 

 Bridge, on the table of rock lying below ; and one on the island im- 

 mediately above the Chaudiere Falls, of much greater size. Dana 

 states that notliing but moving ice could have transported the 

 drift, with its immense boulders. In the glacial regions of the 

 Alps, ice is performing this work at present. In that locality 

 there are evidences of stones of great size, which have, in former 

 times, been borne, by a slow moving glacier from the vicinity of 

 Mont Blanc across the low lands of Switzerland to the slopes of 

 the Jura Mountains, and left there, a height of 2,203 feet above 

 the present level of Lake Geneva. The channel of the Ottawa 

 Paver is contracted at various parts by ridges of glacial drift, of 

 boulders running north and south. The nearest of these is to be 

 seen above the mouth of Green's Creek, between seven and eisht 

 miles below this city. In this locality a well-marked line of boul- 

 ders runs quite across the river, and forms a considerable obstruc- 

 tion to navigation during low water, such as we have had this 

 season particularly. Professor Dawson divides the eastern post- 

 glacial beds into two series, the lower a deep-sea deposit, named the 

 Leda Clay, from one of its characteristic shells ] and the upper, 



