216 R&. W. ELLS—SANDS AND CLAYS OF THE OTTAWA BASIN. 
river, though in the clays of the river expansion, known as lake Cou- 
longe, some 20 miles west of this place, at a still higher level, or about 
370 feet above the sea, fish-bearing nodules are obtained similar to those 
so abundant in the vicinity of Greens creek a short distance below Ot- 
tawa city. Along the line of the Gatineau Valley railway also this bar- 
ren aspect of the marine clays is a marked feature. In none of the cut- 
tings along this section, although they are numerous for many miles, 
were fossils found, except at the summit of a sand and gravel excava- 
tion near the village of Chelsea, at an elevation of about 450 feet. A 
few miles east of this place, near Cantley, the clays contain a few shells 
at about the same height, while at the outlet of McGregor’s lake not far 
distant a great quantity of shells were observed, apparently from the 
sands of this area and at the same elevation. There is no break appar- 
ent in the deposition of these beds, from the nodule-bearing clays near 
Ottawa to the most northerly outcrops on the Gatineau and the Lievre 
where the clays are, in so far as yet known, all barren. 
The origin of these apparently barren sands and clays over such wide 
areas has been a subject of discussion for some years and has given rise 
to considerable diversity of opinion. Their extension northward beyond 
the height-of-land towards James bay, where they are apparently similar 
in character to those along the Ottawa, and their presence over so large 
an area to the south of that river give these deposits a breadth of some 
hundreds of miles from north to south, with a corresponding extent from 
east to west. 
The denudation must therefore have been enormous over a very large 
area, and in support of this view it may be mentioned that outliers of 
the Black River limestone are found at many points from the lower part 
of the Ottawa to lake Nipissing, sometimes in areas of considerable ex- 
tent, while in other places the exposures are limited to only a few hun- 
dred square yards. The inference therefore is that this formation, as 
well as several of those which overlay this to the upper Silurian, once 
extended over a large portion of the Ottawa basin, and these have in 
great part been removed, so that only comparatively small portions of 
these sedimentary formations now remain. 
EVIDENCE AS TO THE ORIGIN OF THE UNDERLYING CLAYS 
The underlying clays at the higher levels up to nearly one thousand 
feet, and in places toa height considerably more than this, are apparently 
continuous with those of undoubted marine origin to the north and east, 
and the inference naturally follows that all these deposits were laid down 
by the same agencies. The absence of marine organisms over a large 
