129 
during the time of maximum marine submergence this 
point was submerged to a depth of over 200 feet (60-9 m.). 
Some of the highest localities at which marine organ- 
isms have been found in the sands and clays of the Ottawa 
district may be briefly stated. In a cutting a short dis- 
tance north of Chelsea station on the Gatineau Valley 
railway, about nine miles (14-5 km.) north of Ottawa, 
stratified sand, interbedded with clay, contains an abun- 
dance of marine shells, the commonest of which are Sax1- 
cava rugosa and Macoma fragilis. These deposits have 
an altitude of about 425 feet (125-9 m.) above sea level. 
About six miles (9.7 km.) south of Ottawa along the Rideau 
river a section is exposed showing 70 feet (21-3 m.) of 
siratified clay followed by 40 feet (12-2 m.) of stratified 
sand rich in similar marine fossils, the whole reaching 
a height of 350 feet (106-6 m.) above sea level. Near 
Smith Falls, about 45 miles (72-4 km.) southwest of Ottawa, 
the bones of a whale have been found in a sand and gravel 
deposit at a height of 440 feet (134-1 m.) above sea level. 
Marine fossils are also recorded near the village of Galetta, 
about 30 miles (48-3 m.) west of Ottawa, at an altitude of 
475 feet (144-7 m.), which is so far as known the highest 
point at which marine fossils have been found in the 
district. 
Above the highest point at which marine fossils are 
found in the vicinity of Ottawa the slopes and character 
of the surface are unfavourable for the record of wave 
built features. Below this altitude, however, well defined, 
though not strongly built beach ridges and terraces, 
marking short pauses in the emergence of the land from the 
Pleistocene sea, frequently occur. Several of the terraces 
are well seen seen along Gatineau river a short distance 
north of Hull, across the river from Ottawa. 
The marine sands and clays are widespread in the 
Ottawa district and at some points are known to attain a 
maximum thickness of nearly 200 feet (60-9 m.). 
The clays are found either unconformably overlying 
the boulder clay or resting on bed rock. Occasionally 
layers of gravel or sand are interposed between the boulder 
clay and the overlying clay. 
The clays are bluish grey toward the bottom of the 
deposit, changing toward the top to rusty grey or brown, 
owing to oxidation of their iron content. Stratification 
is a pronounced feature of a portion of the clays, but 
32224—9 
