A6 MR. H. B. STOCKS ON THE ORIGIN OF CERTAIN [Feb. 1902, 
5. On the Optcin of Certain Concrerions in the Lowzr Coat- 
Measures. By Herpert Birtwuistre Srocxs, Esq., F.I.C., 
F.C.S. (Communicated by Prof. W. W. Warts, M.A., F.G.S. 
Read November 20th, 1901.) 
In certain restricted areas of the Lower Coal-Measures at Halifax in 
Yorkshire and at Oldham in Lancashire, and in a seam of coal 
called the ‘ hard-bed coal,’ peculiar nodules or concretions occur. 
These concretions, termed locally ‘ coal-balls,’ are disseminated 
throughout the coal, not in particular lines but quite indiscri- 
minately. Theyare spherical or ovoid, sometimes slightly flattened, 
and externally—by contact with the coal—they have been blackened; 
though when broken open they are found to be pale or dark brown 
internally, and often streaked with veins of iron-pyrites. 
Some years ago I made analyses of two of these concretions,’ and 
the results are tabulated below :— 
I. II. 
Per cent. Per cent. 
Ferrous OXI06 ..-..c0sssecseetecs oe cee tuos: Bh 3°21 0:16 
MANCANOUS ORIG soi. 2sko darks sateeedesbareacee trace — 
PAR ING: ho50nts cay cco capetenn rede ce nen sheen 0°35 trace 
Dah ee ee ccges A Fil po Sa an 8 OR oto. ge ee amen 36:17 46°10 
NT BRB wceiscpichse cv geusahanetans Cone cteeee 0:88 0°30 
11 RY Se ee at ee er SA aE Ce ong 1°16 1:21 
Silohuric acid 1.5, :.sccsaaeenssetesanostactacnans 0-15 001 
atari yi aioe wo des Saws ta Ree ieee? trace — 
Cae nit, BiG occ: Sontcecesaveoncech eects eee 29°00 35°28 
PAOSHHOLIC BOW | 65) acs hness<sanancrascicrpacer veges trace trace 
TRONADYTILGR 0. agen Wesgroes- + teas ognseansrenaeeese 21°58 12°16 
WY BION voknca does cethe cee Wer tres age teen ee eee 0°31 3°01 
Organic matter and undetermined ............ 721 P77 
From these figures the constituents of the coal-balls are calculated 
to be:— 
I, II. 
Per cent. Per cent. 
Perrous Carbonate sink eos sevs «ded deters oe se 6°00 0°50 
Calcinm-earbonate @)isicciadscan le srcneeewene es vs 64°41 82°32 
Magnesium-carbonate  ..........pssscrcescererses 1:82 0°61 
Calcinm=slp bate: voneccs-resaner-neecs= se rcees ror. 0°32 0°03 
TRO -YPIECS caw ptereseonene rescore oseiitecanney os 21°58 12°16 
Almiaing: 2B oot eoccee sce carecncceciepeseconesees bong’ 0°33 trace 
SUDA i Basics Sorsbecetenns Nodean eacneeeseaeent soles 1:16 1:20 
Hiyproseopic water, .n.p-.5-eesccreesase mnie he 0:25 3°00 
Organic matter, etc. undetermined. 
The nodules or ‘ coal-balls’ are of great interest, because they 
contain extremely well preserved vegetable remains, sections of the 
concretions revealing the internal structure of Coal-Measure plants 
in a very remarkable manner, and it is from such sections that our 
knowledge of the structure of the Carboniferous flora has been 
largely increased. 
1 Proc. Yorks, Geol. & Polytechn. Soc. n. s. vol. vill (1884) p. 394, 
