[blls] geology of the oil-shales of SCOTLAND S7 



2. The Millstone-grit, consisting largely of grey sandstone, shale 

 and conglomerate, the latter often largely made up of pebbles of white 

 quartz in a rather coarse grey gritty paste, in this respect agreeing 

 closely with the lower part of this division in Canada. Beds of chocolate 

 or purple coloured sandstone and shale also occur as a part of the for- 

 mation, as well as thin beds of coal, so that the rocks of this formation 

 as developed in Scotland and eastern Canada are practically identical in 

 character. The formation passes upward conformably in both countries 

 into the productive coal measures. 



3. The Lower Carboniferous formation or marine limestone series. 

 In eastern Canada this division carries large deposits of gypsum. In 

 Scotland, however, the gypsum appears to be almost entirely absent. As 

 there developed it embraces three divisions of which the upper contains 

 several rather thin limestones with thick beds of sandstone and some 

 thin coaJs ; the middle division contains several valuable coal seams with 

 bands of ironstone; and the lowest carries several beds of marine lime- 

 stone with sandstone and shale, a few thin coals and ironstone bands. 

 In the occurrence of workable coals this part of the Carboniferous series 

 differs from the Lower Carboniferous of eastern Canada, in which so far 

 as yet examined, no workable coal seams are known to occur. Below this 

 is, 



4. The Calciferous sandstone formation or oil-shale series. It 

 comprises two divisions, the upper of which is regarded as conformably 

 beneath the marine limestone of ISTo. 3, and is known as the oil-shale 

 jgroup, having a total thickness of more than 3,000 feet. In its upper 

 part it carries two thin seams of coal, usually of inferior quality, and 

 lower down ten or twelve seams or beds of oil-shale, varying from two 

 to eight feet thick which are mined and largely utilized for the manu- 

 facture of crude oil and sulphate of ammonia by distillation.- These oil- 

 shale bands are interstratified with beds of sandstone, shale, marl and 

 estuarine limestone. The lower part, in which no oil-shale appears, con- 

 sists of sandstone, both white and red, with shales of various colours. 

 Volcanic rocks, mostly diabase, are intrusive in the shale series, and ar- 

 gillaceous limestones or cement stones also occur. The rocks of this 

 division rest upon the upper Old Eed sandstone, regarded in Scotland 

 as representing the highest member of the Devonian series. 



In the upper division the presence of thin coals of inferior quality 

 corresponds closely with the occurrence of certain coal beds which are 

 found in the similar formations in Nova Scotia as in Antigonish and at 

 other places, which according to the geologists working in that area are 

 now regarded as probably in the upper part of the Devonian system. As 

 yet none of these coals have been found to be suitable for a fuel supply. 



