WHITE.] 



MOTES ON CHARACTERISTIC SPECIES. «^^ 



verv compart, v«-v open, usually touehin.; or .^lightly overlapping, 

 teneeolate or oblong lanceolate, acute or sometimes obtusely acute, 



^T- Imit;:?:^ sman. 1.25 to . nun. long. 1 to « nuu. wid.^ ^Heniat. 

 usuallv .-ontiguous or slightly overlapping, crowded my Igl y 

 inflated, generally ovate, the lowest reniform-ovate, s^tb dsbUb 

 api.-ulate. dilated near the base, conspicuously const. U'ted at the 

 'ft ide of the rather broad attachment, those ot the m.ddle^ix. - 



ions dilated-ovate or ovate-triaugular. apiculate or "huse^^the ter- 

 minal usuallv short and obtuse or apiculate, or, at the end ot the 

 n Itiniate pinna., slightly sinuate-margined, acute or mucronalx., 



ai 1 ick. very mucS inflated or arched and smooth ven.rally. the 

 Inlrrius curving -strongly backward, and decurnng in a narrow wing 



'"'Ner^tior l^her coarse, the nervils concealed on the ventral su. 

 fac'e Init somewhat distinct on the concave dorsal surface of the 

 pinn'ules. primarv nerve strong, originating at a narrow angle and 

 si vplv marked in the largest pinnules by a vanishing furrow on the 

 , d urfaceof the lamina; nervils originating at a - her nariw 

 m those in the lower part of the pinnule arching near the primaiy 

 rvc" and passing, straight or curved, relatively close together, the 

 l^vcVones flrking^once. or rarely twice, the upper nervUs often simple. 

 This the .smallest form of &<^ Man.^derh group known to me, is 

 un ,, lu". ot onlv for the minuteness of its pinnules, but tor the degree 

 : '.':ir inflation and for the crowded arriuigementot^he ,jii>nu 

 and pimne. The fragments represented ,n PI. CXCII. Figs. - <•. aie 

 of the average form and size, such examples being abundantly dis- 

 persed on some of the shale slabs from the Lincoln min.-. 

 ' Both 2[an.,,f.rU„..a and M. P^f'P^^^'^^f^f;';^^^ 

 forms of Jf,„-;ol>t..n. that is almost exclusively conhned to the bewanee 

 ■ppe, Lvkiis division of the Pottsville series. The smallest repre- 

 nta ves are seldom found outside of the uppermost beds of he 

 ■^ vlnee division. The fern from the Tremont region, which l.s hai dly 

 m::Xau varietally diflerent from '^^^'^!^'"'f'^!:'^^^^ 

 «t lemon-s coal mine, in the "coal bearing shale ot \\ ash ngton 

 dm t Vrkln.sas. is evidently closely related to that described ,n 

 ~;ipt bv Dr Newberry as /',«,*-« !,rff«M from the Sharon 

 ;r^ , theastern Ohio. Both plants, each of which is very abun- 

 . t , „ i, ,,!', loi-alitics. are very rarely found at the same locality, 

 ■ • 1/ I, iu..- c.enerallv confined to lower beds in the Sewanec zone. 

 Thf / , i rela ."s "( the plant from New Lincoln and that from 

 thJsh.u Old are corrobonitively indicated in the Pottsville Ba^n 

 IF bv he presence of the .Vrkansas form mentioned above in the 

 ::t\l u'^N:: Lincoln. TI,.. latter is ;H.^tin."f cd f^m the no. 

 ,„„| .1/. ;,,,,,„.,,„ by the rather larger, thinner. I.'ss ,nfl.it«l. 



