THE EVOLUTION OF COAL*

CARBON PCRCENTACE

CIIE>IISl'I1Y AND INDUSTItY 131

%'!b of volntilc niut..tcr ; iis oiic 1)nsscs out froin i t i n nny tlircction tlic voliitilc content iticrciiscs, nttiiining thc viili1c of %','h o1i the const south of Sciiliit~n :ind .lO'l/o 5 iiiilcs ciist of 13isliop ti11ckliin11. The sltiipc of tlic isovol ciirvcs scctiis to bc :issoci:itcd with tlic itplift,~ to wliic:Ii t,lic striit.ti of t,lic district lm-c liccn sulijectcd ; iigiiitt, tltctt, it; is not iinlikcly t l tnt tlic cliic 1.0 the

t,ions of prcssitrc ivlticlt the region hiis iiiitlcrgotic. iirriiligcIitct1t of tltc CIII'VCS is to Iic sollglit in tltc vitriil-

Itclarrlitty 1 iIJIiicticcs

Jlcrc wc cntcr uricsplorcd territory, nntl i t is ncccssiiry to proccctl with circiiuislicctioii. \ V h t tire the fiicts IciitliIlg to the conclusion t h t ; iiifliicnccs nr conditioiis csist ivliiclt inipcilc tltc evolution of conl nntl i n soritc instiinccs inliiliit i t ?

I'crlinps tlic Inost strilii~ig csnniplc of iirrcstctl coiilifi- c:itiori is tliiit. of ligiiitc tlcposits occiirriiig iii Iinrizoiitiil strata i n tlic Noscow Iinsin. Of Lowcr C'iirbonifcrous

ni!v(trtIiclcss rcniiiiii i i t this ciirly stiigc of tlcvclopnicti t- froln w l i i i t ciiiisc is iittlilio\vit.

0cciisioii:il lcnticlcs of aoiil iirc ciicoiiiitcrctl i n oilsliiile seiiitis ( IAJwrr (~iirl)oiiif(!r~iiis) i n t lic l,ot.ltiiiiis. M y iiiinlysis of onc of tltcso, fniintl in tlic JWls sliiilc, giivc 2*X'!h i i d i , r','; iiioist,urc, ii1id 110 ICSS t l l i i I i SS',!;, \.oliitilc Iiytlrociirl)otis. 'I'hc coiil iviis not ii ciiiiii(!l : it. wiis i i \vcll-clciitctl cliiriiiii wi th fnir coking ~)rii~icrtics. I b \\'iiS,

i n fiict, i i cciiil t liii t , dicniiciilly, I i i i t l not got Iicyotitl tlic lignite stage ; and, i n this instiincc9 its ctivironiiicnt liiiiy l i i i \ v Iiiitl n good t l r i i l to do w i t h its friistriited tlcvi~lop- 111l!11 t.

A ciiri~iiis, sect ilc, tiilc-like sliiilc I N niiiilstonc lies i n some pliic:cs iirttlcr tlic Ihrriicks Oil Sl1iilc. Cutting into II pii!cc of it., 1 c:inic ~icross n stiiiill twig i i i tJic ligiiitous condition. 'I'Iic filw wiis clciirly tlisccrnil)lc niitl the twig wiis iis ficsihlc iis if titkcti froin n recent piit-bog. Agnin, tlic cnvironnivnt; sccttts to Ii i i~c iirrcstctl coitlifi- c ~ i t ioii.

I j u t i f ciivirotiineiit is ii fnctor i t 1 the prol)leni, its c!ffccts niiiy most: 1)rofit.iil)ly 1)c stucliccl i n their Ixxring on tltc phI)lcs of co;iI wliicli Itiivc 1)ccii ol)scrvccl in cotiglotni!riitcs i i n t l Iirccciiis of Crctiiccoits, J iiritssic, I'erini;iti, i i n t l C!iirl)onifc!rniis iigcs in miiny distl.ict.s in (:rait I h i t i i i i t i i n t l iil)roiid.'* 'Illicsc pi!lililes, torn off (Iiiriitg tlic vrosion of tlicir piiretit Iictls, rind t licri I'C- tli:~iositctl iilong \vit,li other tlctl.it,iis of coiil I I I ( ~ I I S I I ~ ~ rocks, iirc foilnil i n i l l 1 c+otttlit;ions. Sonic iirc rountlctl ; i d

;Ig" illid t.llcrcforc olllcr tllilll 0111' l)\vn COIIIS, tllcsc I)I!tlS

~ v ~ l t ~ ~ r - ~ ~ ~ l ~ r t l , otilcrs ilre s i l i l r l ~ - e o r l l ~ ~ r e ~ ~ rril~ll lcllts ; sollie Inllst~ hil\~C 1.icen 1111rl1 I,cforl? tllcy \vcrc t~rrlns]'ortcd frotll t.Iti4r soitre(', while d i c r s initst; Iiiivo I~ccit soft, ; i t , t l i i i t time ns t h y l ici ir t l i a iniprcss of iitljiiccnt Iiicccs : i i i i t l tho cntiI of wliicli t h pclihlw iirc coiiijmsid is of cvrry riinli froin ligitito 1.0 ititt:ltriic~itv. Kot. only is gri.ilt tlivcrsit.y of fortit i i n t l coniliiisit,ion oliscrviilili! i i i cod Iwlilhs fron i cli{fcri!iite Oeds, l i u t sotiictiiiics Iii!lil)lcs lying iieiir togc1tlic:r i n tlte siinii: I)cd cisliiliit w i i h tlificr- wiw. L\niong 1 I I P iiistiiiicvs o i l rccortl iirit itiiiiiy in wliicli t Iic ~wIiIiIi:s I i n \ ~ ! , (litring t lc l i i t , i t i t i i i i i~ i i t i i ) i i , Iicl)t stel)

* I'NJf. S. Stiiiitior. . \ t in, Soc. Suiottt, I~ritsc*llcti, 1!):10, 50, U , :).I, giviw t i t i itp.to.iliiti! ds i t t t ih of oiir ktio\vlctlgu of tri1111 ~ i ~ b l ~ l ~ ~ . 1 1 1 his iqiiiiiiiit, II c l~ i scr~t i i t l g of tliuiti \riiiilil t l iro\v stiitic light 011 t t i i i ~ t i ~ r s rvliititig to t I io civoliitioti of ctitil \vhic*Ii IIL Iirusctit ~ i w ( 1 I itic ii w.

with t,ltc pnrent deposits, nnd con.5ist. of coiil of thc stinie cliciniciil iind ~iliysiciil cltiirirctcr :IS tltc latter ; but, with sonic tlt coii lificiit ion proccss hiis 1 i(:(!ii rctii rdctl, :i n t l with otlirrs i t Iiiis liccii cntircly clicckctl, t,Iic niiitcriiil of t . lt(~ pclillcs rcitinining in t,ltc contlitioii of lignite. Wow ni i t l t.licn, ;IS :it; Corninentry, Ihinw, pdililcs in tlicse tltrcc conditions occur tngctlicr in i t . siiiglc Iictl of conglonicriitc~.

I Itoiigli instiiiiccs of rctnrdiitioii arc niiiny, J know of iione indic:tt,iiig that, conl pcIili1vs iiiiiy on occiision evolve :it ;I ninrc riipid rntc t l r i i n tho parent scoiiis. IVliiit- t'\'Pr lie tllc rciIsoI1 for tire ollscr\~l!tl clfccts-\vllctllc*r

igiinlilc to pltysiciil cotitiict, with 1ioii-L'iirlioti1iccoiis inntcriiil, to t,lie Iiick of \viitcr or to its csccss, to tlic sit t i i l l sizo of tlic pclililcs, to tlicir protection iigainst prcssitrc liy thc siirrountling stronger frngnicnts, to t l i c grcntcr or lcss rcntlincss wit11 which tlic g;iseous proiliicts of tlcliitiiiiiis:itioii Iiiivc m t l c tlicir csciij)c, or to so1tiv factor cntircly iiitktti)\vii-tlios(! effects iiiiiy Iiiiitlcr h i t iirc iiniilile to Iiclp i n tlic cvolutioniiry process.

A s ii litst csiiiiiple, :in11 onc in ~vliicli rctnrtlntion njip(hiirs to 11:~vc n diffcreiit eii~isc, I ciill iittcntion to ii thin Ii i i i i t l

of i~t ipi~rc coil1 occurring ovcr cc*rtililt parts of the O\VCW- clriictli iintliriicitc scii i n on t Iic nort Ii-west ern i n i i rgin of t l t c Soutli IViilw field. l i k e most IVelslt iintltriicites, tlic ~.~wcridriieth is vwy pire ; it i t s i i ; i l l~ coritiiins i i l ic i i i t

?',I/, of iislt, iintl : in S-riiy l)lt(it(>~riil)li of :I t l i i i i slice shows tlic iisliy strciiks to I N idrc(p(!ltt. i inc l inpersistent. ( h i tlic otlicr Iiiinrl, t,lia dirty coiil from tlic roof yielded 251',',, of nslt, i incl t i riidiogmpli slio\vetl tlic iiiipurity to I)c tlis- t i h t c i l f:iirly c\.cnly iis niirrinv Iiiitiiitntions througli- o u t tl1c I,nllll. Ancl \vlrcrcils the clciln COill of t l l C SeiIIlI prol)cr licltl only (i.?';;, of \.oliit.ilc innttcr, tlie inipiirc m i l coiitiiinccl lc)..l",,, tlicsc lipires hciitg csl)rcsscil oii i l i a '* itsh-frcc liiisis. 'I'lie dirtfiest; strip of nll (f28';i) iisli) vii~ltlotl 110 less t l i i i t i 13",, of \.oliitilcs, or ovcr t,wicc t,lic Iiroliortion of blic clciin iilitliriicitcl. 'l'lic high pcrcentngc of voliit.ilas wiis only in ii niinor ttegrcc tluc to the dccom- positioti of ciirlmintts in t Iic itiineriil ittiittcr, since, on lioiliiig i i p t,hc fincly j)o\v~lcrctl inipurc coal with iicitl, the loss W:IS ?..I"{, o l i l ~ . iipj)i!:iriince of the iitljiiccnt iiiitliriicitt* : it; wiis lcss lus- trolls i111I1 \YilS \re11 clcntctl.

Itere, tlicti, is u ciisc of rctiirtlccl tlcveloptiiciit for ~vliicli tlic sccrct. is niorc lilicly to I)c tlisco\-crctl, not in any iiifliicncc of ciivironincnt, but, i n tlic coal it.sclf. Il'lic csci:ss of niiitcriil miittcr iincl tlic cvciincss of its dist ribu- t ioii is siiggcstivc. Tlic suI)jcct of rctnriling iiilliicncrs ofTcrs whit , is nll tuo riire tio\vtitliiys-iin itiitoiicliril fitM for rcsciirclt.

I{ EFt:llESCES

r ,

Nor Iiiltl t,lic dirty biind the