FOUND IN CANADIAN ROCKS WESTON. 5 



Ammonites and crustaceans occur. Among these are Ammonites 

 (Desmoceras), Sacya (Forbes), and Ammonites (Haploceras), 

 Beudanti, Brongniart. 



8. The Huronian rocks, which I have described above, Fig. 1, 

 contain many curious concretions. Some of the small islands 

 in Georgian Bay are composed of a calcareous greenstone, in 

 which an aggregate of quartz, feldspar, chlorite, epidote, etc., are 

 found. In this rock concretionary balls an inch in diameter 

 occur, microscopic sections of which show them to be composed 

 of the same material as the matrix in which they are imbedded, 

 both being highly c^stalline, and the concretions having a 

 scoriated appearance. 



9. A soft, whitish limestone from the Cambrian deposits of 

 Cow Head, Newfoundland, is composed chiefly of rounded grains 

 of irregular shape and size, many of which might readily be taken 

 for Ostracod crustaceans, or have a close resemblance to the 

 species Conodona Tateana. The microscope, however, shows 

 them to be concretious,. generally partly hollow and filled with 

 crystalline limestone. In the beds from which the specimens 

 examined came, ten species of trilobites have been found by 

 Dr. Ami of the Geological Survey of Canada. 



10. An oolitic limestone from the Cambrian rocks of the 

 Selkirks, B. C., two miles west of Donald, shows under the micro- 

 scope concentric layers, slight radiating lines and crystalline fibres 

 arranged at various angles transverse to the concentric structure. 

 Fig. 2 is from a micro-drawing of one of these forms, enlarged 

 about 20 diameters. 



FIG. 2. 



