190 



TRANSACTIONS OF THE 



like form, and have sharp angular edges. Its powder is 

 brown ; is free from pyrites and other foreign matter. 

 Burns with a bright flame and much smoke. Does not 

 soil, and is reduced to powder with comparative diffi- 

 culty. Is not fat ; softens and agglomerates in the fire, 

 the pieces frequently retaining their form. It gives a 

 dense coke, which has a high metallic lustre of a steel 

 grey colour. The ashes were free from carbonates, and 

 of a blue brown colour. The relative proportions of 

 volatile matter, bitumen, &c. on analysis of this coal, are 

 eleven parts to thirty-one parts of carbon.^^ 



The Society is indebted to Dr Martin for a splendid 

 series of fossil coal plants, from this mine. Dr Harlan, 

 who has examined them attentively, thinks they can be 

 referred to Knorria imhricata^ tab. xxvi., Lychopodioli- 

 ies dichotomus, tab. ii., and Striaticulmus (species not 

 identified), figured by Sternberg. The specimens, which 

 are all flattened, vary from a few^ inches to a foot in 

 breadth, and were obtained in pieces of from two to five 

 feet in length. Dr Martin, who paid much personal 

 attention to the examination of this mine and its products, 

 informs us, that these '^vegetable remains" lay all pa- 

 rallel to the walls of the vein, which is inclined at an 

 angle of 60 degrees ; but there were others also which 

 crossed it, and these had retained their cylindrical form, 

 although they were somewhat distorted. An explana- 

 tion of the phenomenon has been off'ered ; viz. that the 

 pressure of the walls of the vein, being applied to the 

 sides of the trunks, which lay parallel, would flatten 

 them, while that effect would not be produced upon 

 those which were placed transversely, since they would 

 receive the pressure in the direction of their length, or 

 from their ends. Be this as it may, the transverse cy- 

 lindrical trunks were identical with the others, being of 

 similar texture, and having precisely the same external 

 impressions. The substance of the fossil plant is a dark 

 compact slate, similar to that in which the coal is imbed- 



