LATE PLEISTOCENE OSCILLATIONS. 
7 
continuous emergence of the land took place, but probably with 
a more rapid emergence at the highest levels and a slowing down 
at the lower levels. 
The altitudes of the highest raised beaches at Rigaud and 
Kingsmere show that, in this portion of the Ottawa valley, the 
direction of maximum uplift was probably slightly west of 
north, for the Rigaud locality at which the highest beach was 
measured is about 3 miles south of the latitude of the Kingsmere 
locality and the highest beach at the latter place is 17 to 19 feet 
higher than at the former; but the information is not very 
definite because the rate of tilt is not known. 
Altitudes of Raised Beaches at Lower Levels. 
Raised beaches occur throughout the Ottawa valley at 
numerous localities and at various altitudes, but it is impossible 
in most cases to trace individual beaches for any great distance, 
so that the altitudes of the lower beaches furnish little information 
regarding the direction of maximum uplift and rate of tilt. 
One beach, however, which can be traced for a considerable 
distance, was found to occur in the valley of the Ottawa river 
above the city of Ottawa. This beach probably marks the out- 
line of a lake which was formed after the partial or complete 
withdrawal of the marine waters, for no marine fossils are known 
to occur in its deposits and in the vicinity of Ottawa strongly 
marked river terraces and river gravels occur at altitudes nearly 
corresponding to the altitudes of the beach in the upper part of 
the basin. Altitudes of this beach were determined at several 
localities as follows: 
FEET. 
Two miles southeast of Breckenridge, near the Canadian Pacific 
railway, crest of strong gravel bar 264 
Three miles northwest of Aylmer and one-quarter mile north of the 
railway, crest of gravel beach ridge. 256 
At Aylmer, 100 yards northwest of the Canadian Pacific Railway 
station, crest of strong gravel barrier beach 252 
One-half mile north of Fraser's mills, crest of sand and gravel beach. . 247 
One-half mile west of Taylor's wharf, crest of strong sand and gravel 
spit,.... 250 
One and one-half miles northwest of Dunrobin Post-Office, near the 
cross-roads, crest of strong gravel beach 260 
One-quarter mile northeast of South March Post-Office, base of 
terrace and bluff cut in marine clay 242 
