206 



an large masses in the Laurentian rocks of Ontario, in the townships 

 of Elzevir, Lake and Tweed. 



It is also found in Norway and Sweden where rocks similar in age 

 and character occur. The finer varieties of amianthus and ashestus 

 occur most abundantly in the Alps of Savoy, near the boundary of 

 Switzerland and Italy, and in the island of Corsica, at which places 

 beautifully white silky fibre is found in considerable quantity along 

 with much of the coarser varieties. 



The variety known as tremolite is found in several countries, gene 

 rally in the old Laurentian rocks, in connection with limestone. It 

 consists of long prismatic crystals of white, grey and green colors, 

 but has not the fine fibrous texture of amianthus or chi*ysolite, and it 

 frequently graduates into actinolitic forms. It occurs in the Lauren- 

 tians of Canada and New York where it has been mined for some years 

 to a limited extent. Cork, leather, &c, are also found in rocks of the 

 same horizon, and beautiful specimens of the former are obtained from 

 -the township of Buckingham, in Quebec. The preceding minerals 

 belong to what is styled the group of the anhydrous silicates in which 

 water is supposed, for the most part, to be wanting. 



Of the other varieties, belonging to the talc and serpentine group 

 we find water entering into their composition to a very appi'eciable 

 extent, and they are therefore placed in the group of the hydrous 

 silicates of magnesia. These include talc, soapstone, or stearite, 

 potstone serpentine and a number of other kinds, somewhat similar but 

 not economically important. The composition of all these may be 

 generally stated to be silicn, magnesia and water, with occasionally a 

 little alumina and iron, the percentage of water, ranging from 2| to 5, 

 in talc, to 12^ and 15 in serpentine, so that the distinction between 

 the two groups, the hydrous and the anhydrous, is, in this way, 

 clearly marked. While the composition of talc, soapstone and serpen- 

 tine is to a great extent the same, or with the ingredients in slightly 

 varying proportions, the mineral which we call asbestus in Qaebec, but 

 whose true name is chrysolite, is confined almost entirely to the 

 latter. The serpentine itself is frequently of varying colors, being 

 green, grey, red, yellow and brown, having a hardness of about 3 to 3J, 

 and a specific gravitv of 2.5 to 2.7. It is generally massive, but some- 





