1892 - 93 .] H. B. Stocks on the Lower Goal Measures. 71 
The constituents are probably as follows : — 
Carbonate of iron, . . . 6*00 
0*30 
Alumina, .... 
0*33 
Trace 
Carbonate of lime, . 
64*41 
82*32 
Carbonate of magnesia, 
1*82 
0*61 
Silica, ..... 
1*16 
1*20 
Sulphate of lime. 
0*32 
0*03 
Iron pyrites, .... 
21*58 
12*16 
Hygroscopic water, . 
0*25 
3*00 
A glance at these figures shov;s that 
the chief 
constituents 
carbonate of lime and iron pyrites. 
These concretions are exceedingly interesting because they usually 
contain remains of plants, petrified in such a wonderful manner that 
every cell is clear and well defined, and very different to the frag- 
mentary portions found in the coal itself they have therefore 
engaged the attention of local geologists and others, among whom 
may be mentioned Professor Williamson, the late Mr Binney, and 
Mr Spencer. 
The portions of plants that are contained in these nodules are 
mostly large pieces of wood of species of Sigillaria and Lepido- 
dendron ; very often the whole nodule is one mass of fossil wood 
with a thin coating of unorganised mineral matter. 
Several portions of fossil wood have been removed, and analysed 
with the following results : — 
1. 
2. 
3. 
4. 
Perrons oxide, . 
•79 
3*14 
0*60 
1*91 
Ferric oxide. 
Alumina, . 
*01 
1*60 
0*59 
2*77 
Lime, 
. 48*32 
18-05 
49*61 
30*49 
Magnesia, . 
1*73 
0*71 
1*52 
2*96 
Sulphuric acid, . 
Trace 
6*70 
0*60 
4*32 
Carbonic acid, . 
f Hot ; 
1 estimated j 
|- 11*80 
39*09 
26*80 
Silica, 
• 
0*30 
0*01 
0*08 
Iron pyrites. 
• 35 
48*63 
4*75 
24*25 
Organic matter, . 
' 55 
4*03 
3*43 
4*79 
Water and matter volatile ) 
at 110° C., 
/ ” 
4*25 
0*25 
1*61 
99*21 
100*45 
100*38 
