FLOHA (M" OLDKl! roTOMAC FORMATIUX. 347 



the (lesriii.tion ...•cupyii.- tlu- vvuvauuIw ..f tlie section .-lonrly relates to 



tlie Potomac l)eds. . ,, 



In his paper "On the Ajie of the Coal Koeks of ilastern \ irouna. 

 devoted chiefly to the older of these formations, he refers to the younjjer ■ 

 beds as follows: 



Th.- <-.,ars,.r nu-ks. Ivin-r al-.-vo tl... .■arl.oiuu-.H.us strata, ami lornuii- the -foater 



part, of tlie thi-^kticss of tlic M'ncs. .Hmtaii, very l.w ...-a.ur nMnait.s. an.! those n. so 

 i.uperfoct a conditio., as to hav. little or .... vah... to,- pur,.o>..s ol cou.pai-.s.m. 



The.-o a.-.> hoNV.-v.M-, sf..n- ivaso.ts lor la-H.-vitt- that th.-s.. strata, l.y a -,,uh.al 

 trattsiti...., pass ^p^^a^l i.tto th.. series ..t l.-ispathi,- sa„.lsto...-s, aes..-,!....l ,., n.y 



report of the (u-olo^i.-al Surv..v..f Vii-htia for l,S4(),un.ler the title ..I [ p,,rr .S,co,nl- 

 an, Strata. The latter, ......si.le.ed l.y Messrs. Tayh.r a„.i Clentso,,, as • ' ol s.'e.n.clary 



oriHn perhaps .■o.>val with theOoiites," have since l..vnn.|e,mlhy,..y.selia„.l .-..1. 

 H 1) Ro-ers t.. the upp.r part ..f the Oolite series, s.. that this great division ol the 

 Kcologicarcolunn., though still p.'.haps very in.perlV.-tly ivpresonted in the Fn.ted 

 States, .•..niprises a thi.-kness of considerably more than one thousand ioet ol strata 

 (seep. 301). 



Mr. Richard C. Taylor,, in his work on the Statistics of Coal, published 

 in 1848, returns to this subject " in the treatment of the coals of Virginia. 

 Relative to the lignites, silicified wood, and fossil plants he says: 



In 18134 the Geological Society of Pennsylvania ptthlished in their first v..liime 

 a paper communk'ated l.y the author of this work on the lignites of the secondary hori- 

 zontal strata of Fredericksburg, accompanied by six lithographed figures of plants. 

 These li-nites are in no pla<-e in sutlicient abundaace to constitute a seam or bed 

 „uH'h l.'ss a workable bed. but as interesting specimens of sihcified masses of wo..d 

 •tnd fragments even of large trees, which reminded us of those of the Portland rock 

 of the s'.uth of England; besides an infinite number of impressions and carbonized 

 remains <.f m..re delicat.- vari.-ti.'s .,f plants, that are n..t uu<l.'s.>rvmg ..I a passing 



notic.'. • 11 1 



On l..oking over the imperfectly .lelined s.-ries ..f these plants, .t will b.- sen 

 that they ar.> all crvptogamous. cellulares, or acotyl.-d..nes, with the exceptu.n o 

 Thuvtes au.l that th.'v belong to genera some of whose species are distributed 

 abun.lantlv a.u..ngst the coal vegetation of ail parts of the world. Th.-se speces. 

 however apj.ear to be new-that is, they do not belong t.. the Carl.o...l.M-..t.s p.TK.d 

 One approaches to the Oolite period, an.l the .-onsuhM-ation given to this group of 

 plants I.hI to th.- .•..n.-l..si..n that they were • * p.-rhaps .oeval with the O.ihtes. ' 



" «Trans. Assoc. Am. Geol. and Nat., Boston meeting. 1842, in«l.ulc.l,,l.ia lS4:i pp. -t.s^am. 



ft Page .>4. S.,-ond edition, revised «nd t.rougl.t down to 1854 by S. S. Ilalden.an, PlMladeiplna. lS,o, 

 p. 299. 



