74 



as it is also sometime called, varies from next to nothing to twenty- 

 feet or more in thickness in different places. They are extensively 

 developed about Ashburnham Hill, Gilmour's Mills, near the Hog's 

 Back, etc., occupying their lower and regular position at the bottom of 

 the Post-Tertiary series in Upper Town, Centre Town and Stewarton, 

 cropping out in the rear of the City Hall, on the east side of the canal, 

 and ever keeping in a normal position. This " till " is thence very 

 generally distributed in beds of varying thickness, in the area included 

 in a curve drawn from the New Militia Stores on the canal, along Sussex 

 street up to St. Patrick street, then produced on to the bridges over the 

 Rideau river, pretty nearlv in a line with the curve which Sussex street 

 there describes, and across to New Edinburgh through the Rideau Hall 

 grounds, to a small extent, where these deposits thin out markedly, and 

 continuing the line through Beechwood, in Gloucester, on in a south- 

 easterly direction, we have a horse-shoe cui've, in which are included 

 vast accumulations of material left us by this Ice Period. But to come 

 back to the moraines : there are, besides these hard coherent masses 

 of " boulder clay," large aggregations of more or less uniformly sized 

 boulders held very loosely together, and form a prominent feature of 

 the county. At Gilmour's Mills there is a good example of one of 

 these whilst there has already been pointed out in the "Geology of 

 Canada," 1863 already cited that a number of zones or belts of 

 boulders cross the Ottawa at different places near the city, one of which 

 a few miles below Ottawa produces a shoal on account of which the 

 navigability of the river at this point becomes dangerous and has obliged 

 the Government to erect a lighthouse. These are what are termed 

 *' morainic belts,'' and are prominent features to consider. 



There are a number of other particulars respecting which the 

 detailed notes obtained from the excavations that have been carried on 

 in our streets, though bearing immediately on this subject, cannot be 

 included in the present exposition of the subject. 



(To be Continued. ) 



