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 quarry men. 

 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,havebeen known for many years, and thefossils 

 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 

 a few days. It is a 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 Geological 

 Survey. 

 OTTAWA, March, 1894. 



