134 
_ filled valley of the predecessor of the Ottawa and enters 
the Ottawa near the eastern end of the city with a fall 
over the rock escarpment of about 50 feet (15-2 m.). 
Gatineau river, coming from the north and entering 
the Ottawa nearly opposite the mouth of the Rideau, 
~ appears to follow its pre-glacial course, an ancient valley 
carved in the resistant rocks of the Pre-Cambrian upland. 
Like all the rivers flowing from the upland into valleys 
floored with Paleozoic rocks it has its steepest grade 
near the contact of the Pre-Cambrian with the softer 
rocks. 
ITINERARY “OF EXCURSION: 
Leaving Dufferin bridge on a C.P.R. local trolley 
car and crossing the Interprovincial bridge to Hull, sec- 
tions in a boulder ridge and a quarry in Trenton limestone 
are first examined. Southeastward about a quarter of 
a mile from this point several sections of boulder 1idges 
may be seen. Proceeding by trolley car to the sulphite 
plant of the Eddy paper works, a section showing cross- 
bedded sands and gravels filling erosion channels in marine 
clays may be examined next. 
Returning by street car to Ottawa over the Chaudiére 
Falls bridge and proceeding from the end of the Bank 
street line southward to a sand pit near Rideau river, 
a section of till overlying stratified sand and gravel may 
be examined. 
ALTERNATIVE EXCURSION. 
By taking the boat from Queen’s wharf down Ottawa 
river to Besseier’s wharf, the marine clay at the latter 
point may be examined and concretionary nodules con- 
taining marine fossils collected. 
BIBLIOGRAPHY. 
1. Logan, Sir Wm. E..Geology of Canada: Geological 
Survey of Canada, 1863. 
2. De Geer, Baron Gerard.—On Pleistocene changes of 
level in Eastern North Amezcica: 
Proceedings of the Society of 
Natural History, Boston, Vol. 
XXV, 1892, pp. 454-477. 
