500 MESOZOIC FL();L\S of UMTKl) STATES. 



found, iho rest being generally small fi-agments of leaves. This seems 

 to be t'orroctly sepai'atod from Pojmlu!^ pnlomacetiKis liy Pr )fessor 

 Ward. Il is rarer llian the lattei', only 9 specimens liaving been 

 found. It is eonfinetl to the Mount Vernon locality. PI. CX, I'lg. 5, 

 gives a proportionally broader form than that figured by Professor 

 ^^'ard. This specimen occurs iu counterparts, and was collected on 

 ^hiy 14, 1<S93, along with two others. Of the 5 specimens obtained on 

 Xovcml)er G, 1892, this one is that figured by Professor Ward. 



I'oiTI.lS I'OTO.MACENSl.S Waitl '.. 



This beautifid little loaf was first found by Professor Ward, and it 

 was fully described by him." It is very abundant in the Mount Vernon 

 strata, and in fact seems to be practically confined to them, so that it 

 may be regarded as their most characteristic fossil. A number of leaves 

 may l)e foinul nearly or cjuite entire. This is surprising wdien we 

 considei- their delicate texture, but the fact may be explained by their 

 very small size. 



All liut three of the specimens were found- at the Mount Vernon 

 locality, that represented by fig. 1 of Professor Ward's paper l)eing one of 

 those collected by him on his first visit, on Octolier 16, 1892. His fig. 3 

 represents a specimen tliat occurs on the reverse of one of the counter- 

 parts of th(> type specimen of Antholithes Goiidhim-Rosa, collected on 

 November (>, 1892, and his fig. 2 represents one of the few specimens that 

 were taken on the occasion of my visit to the locality, imder his guidance, 

 on July 25, 1893. It shows the maximmri size. 



Genus POTAMOGETOPIlYLLlTiM '' Fontaine nov. gen. 



The true position of this genus can not be determined from the 

 material at hand, and the generic name is chosen only to indicate its 

 resemblance to Potamogeton in points that may not be essential. 



PoTAMOGETOPIIYLLUM VKKXONKNSE F(intain(- n. Sp. 



PI. CIX, Fig. 7. 

 A very rare leaf, resembling Potamogeton, occurs in the Moiuit 

 Vernon collections, one specimen only being found in comiterparts. It 



" Op. cit., pp. 35,5, 3.56, pi. iv, figs. 1-3. 



''A-stlic second component (ynircor) of the mime Potamogeton is itself derived fioiii ;'ii(, ;'»;, ami 

 its immediate derivative, ;'))r)/;, this shortened form, which drops the characteristic n, \<t fully justified. — 

 L. F. W. 



