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TJie Oversea Dominions of the Empire have had the exploita- 

 tion of petroliferous shales in active operation lor a number of 

 years. In New Brunswick, Canada, a considerable tonnage of 

 shale was mined and exported for distillation during the middle 

 decades of last century, before the discovery of the Pennsylvania!! 

 oils killed the industry. Here the oil shales form part of trie 

 Upper Devonian, and so nearly correspond in point of age with 

 the Scotch shales. The Kerosene oil shales of New South Wales 

 were discovered as early as 1824, and since I860 mining and dis- 

 tillation have gone on actively. These seams of Boghead mineral 

 vary in thickness between 3 and 5 feet and carry as much as 150 

 gallons of oil per ton. Their geological position is in the Permo- 

 Carboniferous strata, and their origin is referred to low organic 

 forms, chiefly algae. New Zealand also gives promise of develop- 

 ing valuable, oil shale deposits. At Orepuki, South Island, a seam 

 4 feet in thickness carries on the average 32 gallons of oil per ton 

 and gives a high yield of sulphate of ammonia. Qil shales are 

 also Worked in the Middleburg Carboniferous area in the Trans- 

 vaal, where a good payable seam 5 to 7 feet in thickness, yielding 

 per 'ton about 80 gallons of oil and 70 lbs. of sulphate of ammonia, 

 has been located. 



Physical Features and Composition of Oil Shale. 



The word " shale " is somewhat of a misnomer and a little 

 misleading. As applied to Kimmeridgean and s : milar beds it is 

 •quite correct, but when used to imply the petroliferous minerals of 

 the type of Boghead Mineral and Torbanite associated with the 

 Carboniferous system, it conveys a wrong impression so far as 

 the physical structure of the mineral is concerned. The shales 

 proper are laminated, with distinct bedding planes, and split 

 easily, whereas Torbanite is quite homogeneous and massive. 



Shales as they are mined are generally classed under one of 

 three categories: curly, plain or paper shales. " Curly" is the 

 richer and most valuable variety, generally dark brown in colour, 

 fairly homogeneous, breaking with a more decided conchoidal 

 fracture than other kinds, and resisting weathering to a marked 

 degree — practically remaining unchanged by exposure to the 

 weather for years. The " plain" shale, which forms the bulk of 

 that treated at the present time, is lower in hydro-carbons than 

 the curly variety and has more evident lamination and does not 

 weather so well. The 44 paper" variety, as the name indicates, 

 resembles very thin layers superimposed one another, united by 

 subjection to great pressure. They split quite easily and do not 

 weather well. 



The Dorset Kimmeridge coal is chiefly brown in colour and 

 plainly laminated. Some varieties, on exposure to the weather, 

 separate into curly layers, while others remain unaltered after long 

 exposures. It is light, though varying in density according to 

 the amounts of inorganic ash. When struck it emits a wooden 

 note. It feels somewhat unctuous to touch, and when rubbed its 

 scent is mixed earthy and asphaltic. 



