300 



THE GEOLOGIST. 



average thickness of 5 feet ; but tlie most important deposit is that on the 

 great slopes of the Beaver Eiver, in Euphrasia and Artemisia, where it is 

 supposed to extend over more than a thousand acres, in the form of a strip 

 on each side of the river. Under the head of mineral paints we have iron 

 ochres of alluvial, and sulphate of barytes of Laurentian age. The 

 barytes of Burgess and Lansdowne is derived from veins intersecting the 

 Laurentian rocks. At both places the mineral, associated with calcspar, 

 constitutes the veinstone of some of the lead lodes met with there. The 

 vein yielding the Lansdowne specimen cuts Laurentian limestone. In an 

 unsuccessful attempt to mine the vein for lead, it was ascertained that 28 

 feet of the lode, with a breadth of 27 inches, consisted of highly crystalline 

 almost colourless barytes, yielding about 10 tons to the square fathom. 

 The most abundant source of barytes in Canada, so far as is known, ap- 

 pears to be the veinstones of lodes carrying copper-ore on the north side 

 of Lake Superior ; these however belong to the Quebec group. In Canada 

 this mineral is not as yet applied to any use, but in some parts of the 

 United States it is refined and ground in large quantities for use as a 

 paint. 



Amongst the minerals applicable to the fine arts, forem.ost is the litho- 

 graphic stone (Bird's-eye formation) from Marmora, where the Laurentian 

 rocks are overlaid by 20 feet of unfossiliferous compact limestone, one of 

 the beds of which is well adapted for lithography, and has been traced by 

 occasional exposures from Hungerford to Rama, a distance of more than a 

 hundred miles. Lithographic stone is also shown from the Onondaga for- 

 mation at Brant and Oxbow. 



On the minerals applicable to jewellery we shall not dwell at any 

 length. We have agates, labradorite, albite (persisterite), orthoclase (perth- 

 ite), jasper conglomerate, epidosite. 



In the miscellaneous minerals we have feldspar (from a 20 feet wide 

 Laurentian), sandstone for glass-making (Potsdam), moulding-sand (drift), 

 and peat (alluvial). The peat exhibited occurs near Chambly, on the south 

 side of the St. Lawrence, and was some years ago cut and sold as fuel, but 

 the consumption was not enough to encourage the industry. As Canada 

 is deficient in coal, when wood becomes scarce in the progress of set- 

 tlement peat will gradually assume some importance as a fuel in many 

 parts of the country. About 100 square miles of it extends along the 

 south front of the Anticosti, and successive areas are met with on the south 

 and north sides of the St. Lawrence. Large peat bogs occur between the 

 Ottawa and the St. Lawrence, and there are many to the westward. The 

 peat, which is sufficiently matted to hold together when dried, usually sup- 

 ports a growth of prairie-grass, or ericaceous plants, or of tamarac-trees. 

 Til at which occurs in cedar-swamps is deficient in the fibrous plants which 

 give cohesion, and it falls to powder when dried. 



The Survey also exhibits an admirable collection of the crystalline rocks 

 of Canada, arranged under these respective groups: — I. Laurentian. II. 

 Iluronian. III. Lower Silurian ; and TV. Eruptive ; accompanied by an 

 excellent catalogue by Mr. T. Sterry Hunt. We cannot however give a 

 special notice, however richly it deserves it, as we have already devoted a 

 very considerable space to the Canadian collection ; but the interest which 

 attaches to it as representing that country, where, more than in any other 

 part of our glol)o. the "bottom rocks" of the earth's stratified crust are 

 most grandly ox])oscd, warrants the fullest attention ; and the numerous 

 facts which are thus briefly but accurately recorded will be found here- 

 after of the highest value in considerations of the circumstances producing 

 and attending the earliest history of our lowest life-containing and our 



