no. 8.] spencer — geological sketches. 471 



Minerals. 



A few minerals can be obtained in tlie neiohborhood of Hamil- 

 ton. They are not rare species, but still are not without interest. 

 In the thick five-foot niagnesian limestone band of the Niagara 

 formation, there are geodes lined with calcite (dog-tooth spar), 

 barite, celestite, selenite, granular gypsum and pyrite ; and often 

 the cavities are filled with highly saline waters. Besides these, 

 quartz crystals, chalcedony, galena, blende and sulphur have been 

 found. 



Near the junction of the ravines from Webster's and Spencer's 



Falls, there is a locality where an efflorescence of the following 



composition is found : 



MajJ^n(!siiim sulphate 61.450 



Calcium carbonate 19.532 



Ferrou.s carbonate 12.850 



Calcium si licate 2.741 



Silica 3.427 



100.000 



It is evidently the result of the decomposition of pyrites in 

 presence of dolomite. 



Mineral waters — both saline and sulphuretted waters — occur 

 in numerous localities. Of the latter class may be mentioned 

 several springs near the Albion Mills, five miles east of Hamilton, 

 which give off large volumes of gas. 



