FOUND IN CANADIAN ROCKS—WESTON. 9 
16. Besides the large trunk-like cylindrical concretions found 
in the Potsdam sandstones on the banks of the Rideau Canal, near 
Kingston, Ont., (Trans. Nova Scotian Inst. of Sci., Ser. 2, Vol. I), 
there are many “stone potatoes,” so-called by the quarrymen. 
These are spheroidal forms generally distorted, varying from 
the size of a rifle bullet to three inches in diameter, and com- 
posed of fine grains of translucent quartz. Many of them are 
stained with oxide of iron, while others are of a dirty white, the 
colour varying according to the tint of the rock in which they 
are enclosed. In some of these, concentric layers are faintly 
seen, but no radiating lines. 
17. Hard calcareous concretions (nodules, as they are gener- 
ally called), are among the most interesting objects of the Post- 
Tertiary (Leda Clay) deposits of Canada. The clay banks of 
Green’s Creek, and the south shore of the Ottawa River, a little 
below Ottawa city, have been known for many years, and the fossils 
contained in the concretions of these localities recorded by many 
writers ; but a few words here may not be out of place. The 
kidney form is the most common shape taken by these concre- 
tions, which generally enclose the skeleton of the well-known 
Green’s Creek fossil fish, hundreds of which may be collected in 
afew days. It isa capelin, Mallotus villosus (Cuvier), in some 
cases so well preserved that every bone can be seen. Other 
forms are spheroidal, and contain for a nucleus a fragment of 
bone, a shell or grain of sand, or an insect. A large collection 
of these fossil bearing nodules or concretions was made by Dr. 
Ells of the Canadian Geological Survey during the summer of 
1893, from Besserer’s wharf, on the Ottawa River, near the mouth 
of Green’s Creek. In one of these a fine leaf of Populus 
balsamifera was found. 
In Sir J. W. Dawson’s “ Canadian Ice Age,” a detailed account 
is given of our Post-Tertiary rocks, with illustrations of some 
of the principal fossils. Besides the common capelin before 
mentioned, we find the well-known mussel shell, Mytilus edulis, 
Linn., and two or three beetles, among which is byrrhus Otta- 
waensis, the latter collected by Dr. Ami of the Geologica] 
Survey. 
OtTTawa, March, 1894. 
