72 Proceedings of Eoyal Society of EdinbiirgJi. [sess. 
The constituents are probably as follows : — 
1. 
2. 
3. 
4. 
Carbonate of iron. 
. 1*44 
5*77 
1*12 
3*57 
Ferric oxide, 
1*60 
0*59 
2*77 
Carbonate of lime, . 
. 86*30 
23*88 
87*01 
49*05 
Carbonate of magnesia. 
. 3*63 
1*49 
3*19 
6*21 
Calcium sulphate, 
{ Not ) 
( estimated J 
14*40 
1*29 
9*28 
Silica, 
J5 
0*30 
0*01 
0*80 
Iron pyrites. 
48*63 
4*75 
24*25 
Organic matter. 
4*03 
3*43 
4*79 
Hygroscopic water, . 
JJ 
1*37 
No. 1, of which only a 
partial analysis was made, was a specimen 
of Sigillaria vasculare. No. 2. Species not known, dark brown in 
colour, with a large quantity of iron pyrites running in parallel lines 
along the grain. No. 3. It was a specimen of Sigillaria, very hard, 
with no pyrites apparent. No. 4 was a specimen of Lepidodendron 
Sternl>ergiij black on the surface, brown in the interior, with much 
pyrites apparent. 
The organic matter was determined in order that an idea might 
be formed of how much of the original substance of the plant 
remained, and in the three examples given the amounts were very 
close together ; that is, about 4 per cent. In every case, on treating 
the specimen with hydrochloric acid, an odour of petroleum was 
perceived, and the residue contained fragments of but slightly 
altered cellular tissue, showing that the process of petrifaction was 
not complete. 
Bischof, in his Chemical and Physical Geology^ gives us a similar 
case to the above. He says : — “ On treating a Stigmaria fucoides, 
fossilised by carbonate of lime from the transition formation, with 
diluted hydrochloric acid, Goeppert obtained a residue presenting 
the entire structure of the plant in its natural arrangement and 
colour. The wood of Coniferae from transition rocks left only *02 
to 0*7 of feebly brown, perfectly flexible fibres together with some 
empyreumatic oil smelling like creosote.” 
Suggestions as to Formation of the Coal-Balls. — Mr Binney has 
stated {Manchester Geological Society's Reports and Journal of the 
