152 THE CANADIAN NATURALIST. [Vol. X. 



many large cavities of several inches extent filled with foreign 

 minerals, which will be noticed further on. 



Calcium carbonate 59-7 



Magnesium carbonate 38 2 



Alumina and oxide of iron 1-5 



Silica 0-4 



99-8 



Analysis III. — The bed from which this sample was taken 

 is about five feet nbove No. 8 of section, and is one of the 

 harder and more compact layers (No. 9 of section) of that por- 

 tion of the geological horizon which I have identified as the 

 Niagara shales at the ''Jolly Cut," Hamilton. It is said to 

 produce hydraulic cement, but if so it would be of inferior 

 quality. 



Calcium carbonate 33-8 



Magnesium carbonate 25-2 



Calcium silicate 6-6 



Magnesium silicate 2-7 



Alumina 5-1 



Ferrous carbonate 1-8 



Ferric oxide 1-6 



Ferrous disulphide (Pyrites) 1-9 



Silica 20-0 



98-7 



Andlysis IV. — The sample for this analysis was obtained 

 from the ' Cheit bed " (No. 12 of sections). The portion taken 

 was free from cherty concretions, as these portions would be 

 nearly made up of pure silica. Under the microscope there 

 was only the usual crystalline structure of the dolomitic particles 

 peparated by dark earthy matter. 



Calcium carbonate 46-6 



Magnesium carbonate 38-9 



Calcium silicate 



Magnesium silicate 



Ferrous oxide 0-8 



Alumina 2-4 



Silica 93 



I 2-8 



100-8 



A large number of other specimens were examined under the 

 microscope, but they were all of essentially the same structure, 



