140 



MINERALS AND GEOLOGY 





FIG. 83. 



Hopper-shaped" 

 cube of salt. 



imparted tints being mostly red, brownish, violet-blue, yellowish, or 

 pale-green. Streak, white. Crystallization, Regular : 

 the crystals usually cubes, often with hopper-shaped 

 depressions on each face the larger crystals being 

 composed of numerous minute cubes so arranged as to 

 produce this peculiarity. Occurs also in lamellar and 

 and granular masses. Cleavage, cubical. H = 2.0 

 2.5; sp. gr. 2.1 2.25. Taste, strongly saline. 

 BB, decrepitates strongly (unless very dry), and melts into an 

 opaque bead, which colours the outer flame intensely yellow. Nor- 

 mal composition : chlorine 60.66, sodium 39.34; but usually, small 

 portions of chlorides of magnesium and calcium, and sulphates of 

 lime, magnesia, and soda, are also present. Most samples contain 

 likewise a certain admixture of clay or other impurities. 



A deep boring on the bank of the River Maitland near the town 

 of Goderich, commenced at the close of 1865 in quest of rock oil, has 

 yielded an abundant supply of strong brine cf remarkable purity 

 thus indicating the presence of a very extensive deposit of salt below 

 this section of the country. The boring has been carried down from 

 the surface gravel and underlying Corniferous Formation into and 

 apparently through the G-ypsiferous or Onondaga strata (see Part 

 V.), the total depth from the surface being a little over one thousand 

 feet. According to Mr. Platt, who conducted the boring, salt in 

 solid layers was reached at 964 feet from the surface, and the total 

 thickness of these layers, exclusive of some thin partings of salt- 

 bearing clay, averages about thirty feet. An analysis of the brine by 

 Dr. Sterry Hunt, shews it to be a saturated solution, containing over 

 26 per cent, of saline matter : 25.90 (equal to 99.018 per cent. ) of this, 

 being pure salt or chloride of sodium. (See Geol. Reports 1868 and 

 1869, for various comparative analyses, and much valuable information 

 on the Goderich and other brines, by Dr. Sterry Hunt.) Salt has also 

 been subsequently reached by other borings at Kincardine, Clinton, 

 and Seaforth, in the same district. At Seaforth, from information 

 received from Dr. N. Coleman, a more or less solid bed was struck 

 at a depth of about 1040 feet. Chloride of sodium occurs also in 

 solution in many of our mineral springs, but only in small quantity, 

 and alwavs accompanied by much chloride of calcium or chloride of 

 magnesium, sulphate of lime, and other saline compounds, which 



