vol 

 1 



kJ^;^'] p].m)CFJ':i)IN(;s of 'iiri': national miisfjjm. 281 



ity fossils iuc coiiipun-d with known phiiits. ()f the liriccn icinaininj;', 

 no less tliiin twelve ai'c. idciiticiil willi plants from tlic ohhu- J'otomac, 

 or are so near them that a strong' 1)1<'siimii>1 ion of the n<';iiness in a^-e of 

 tlie two forinalions is established, ^fhe circninstaiiees nnder wliieh (he 

 basal Trinity beds were laid down indicate tliaf the Ibssils entondied in 

 tlicMii Ibriu a j)ortion of a llora tiiat was established on the land that 

 was enroache<l upon by tlui Trinity sea. It is ])rol)able tinit liiis same 

 lloia extended northward to Vii<;iniii, wheici, soniewliat hitei-, it was 

 ])i'eserved by a simihir enei'oachnient. 



The (Jlen Kos(i, or alternatin<4' strain, in wlii<'h the fossil i)lants are 

 lound, (contain an abundant marine fauna, (rem the evidence of which 

 J'rof. Hill had eoiududed that its aj^'e is Neoeounan, or basal Cretace- 

 ous. No fossil ])lants Inid been hitherto ibund iu the (Joman(;he series, 

 and the evidence of its age was derivc^d wholly I'rom the aidnial re- 

 nuiins. The discovery of ])lants in it was then of special importanc<i, 

 for it enabled us to compare tin; evidence of the plant lile with that of 

 the aidnuil life. It is interesting to (ind so (dose an agreement. This 

 agreement adds one- moi-e proof of the value of tbssil floras in fixing 

 the age of the strata in which tlK^y arci found. 



FXl'LANATIoN <»F I'LA'I'KS. 



I'l.ATK WXVl. 



Fig. 1. Equ'tHclum iexenne sp. iiov. 



Fig. 2. SphenoptoriH valdcnsls Hecr. ? 



Fig.s. 3, 4. Dioouilea Jiucliiaiin,i, \av. larhicrrin var. ii<)\ . 



I'^ig. r>. J)ioonileii JiucliiiuiKx S<'liinii)er. 



Fig. (i. DioimiU'S BitcliiannH var. aiiijnuti/oHiis J'\)iitu 



Fig. 7. I'odozamileH acutiJ'uliiiH J'\)iit. i 



Fig. 8. I'odDZiuiiUcK Hp. f 



F^ig. it. lAirlntpnix loni/ij'olia I'^ont. 



Fig. 10. SpIieiiolcpi(lii(in .Sler)ih('.r(/ianiim \ar. ilmxi folium Foul,. 



Fig. 1 1. I'hiiis 8p. f 



Fig. 12. Uioonitoi Dniikiriauna ((iJip)).) Micpicl. 



l'[..\TK WWII. 



Fig. 1. DootiiltH Piiiiheriaiins ((il<")])|>. ) Miijiiri. 



Fig. 2. Ahirlilr.i Lhik'n (Kofiiii.) i>iiiii<. 



Fig. 'A, 4. Zainitei) teiiiiiuerris Font. , 



I'l.AlK WW III. 



Fig. 1, 2. ZamUen IcHuinervii F'oiit. 

 Figs. 3-5. BraclnijihiiUiim tr.miHr sp. nov. 



I'l.ATK XXXIX. 



Fig. 1, 1(1. Jliucln/jthi/Uiim. Iextti8(' H\>. nov. 

 Figs. 2-11. J'tifjiopln/Uum dubiitm sp. iiov. 



I'r.ATK XI.. 



Figs. 1, 2. Freiiclopxis rariann sp. uov. 



