FORMATION OP COAL AND CARBONACEOUS MINERALS. 127 



marbles, and amounting sometimes to 20 or 25 per cent, of tlie 

 mass. 



2nd. — Those containing iron pyrites but no retinite. 



3rd. — Those containing neither retinite nor pyrites but having 

 much sulpliur in organic combination. 



4th. — Those without retinite, pyrites, or much sulphur. 



Subjected to distillation the lirst and last evolved but little 

 sulphuretted hydrogen, the second evolved much of this gas 

 under the conditions of high temperature, the third both at high 

 and low temperature. 



If we consider these varieties of imperfect coal it appears 

 probable that, had they been subjected to conditions such as 

 would convert them into coal, the results would be very different 

 for each although the conditions were the same. The first is 

 evidently produced from highly resinous vegetation, and would 

 probably yield bituminous coal, and the I'esin gives an aromatic 

 odoured distillate on quickly heating, but the amount of resin 

 available was too small to go into the matter of the products. 

 The second from non-resinous vegetation, the pyrites being formed 

 by infiltration, would yield a coal like the stinking coal of 

 Lancashire or the brassy coal of some of the Scotch mines. The 

 third it seems probable was produced from vegetation containing 

 much sulphur, such as we find in our modern Cruciferte and to 

 this I know of no corresponding true coals. The fourth would 

 correspond to the splint, cherry, and other less bituminous coals. 



Again, the deposit of kerosene shale or torbanite at Joadja 

 Creek consists of three distinct layers, separated by almost 

 imperceptible partings and yet everywhere perfectly distinct. 

 The seam is composed of first, a layer of splint coal containing a 

 rather large proportion of ash, second a layer of shale, covered 

 third, by a layer of bituminous coal of fair quality. In this case 

 it appears that the three layers were deposited in orderly succes- 

 sion and that all must have been subjected to the same conditions 

 since deposition, and yet the ultimate products are entirely 

 diflerent. It may be observed in passing that these deposits of 

 torbanite, both in New South Wales and Scotland, where one 

 only has been found, seem to have been originally laid 

 down in irregularly lenticular depressions, and observation has 

 indicated that they have never been subjected to excessive 

 pressure, as wherever the "cover" exceeds two or three hundred 

 feet the torbanite is found changed into a carbonaceous slaty 

 mass. It is evident that the difierences in the three layers in 

 this seam cannot be asci'ibed to any other causes than an orginally 

 I'adical difierence in the vegetation forming them. Torbanite, 

 Boghead, or kerosene shale, has been legally classed as coal, and it 

 is usually classed with cannels although it is very diff^erent. 

 Thus Wanklyn (loc. cit.) says — " The following is an analysis of 

 one of the richest cannels, viz. Boghead," (the original torbanite of 



