RADSTOCK SERIES OF THE SOMERSET AND BRISTOL COAL FIELD. 369 



between the contiguous pinnules — has induced some botanists to employ 

 Presl's genus Goniopteris for this and some allied species. 



PI. XXIV. fig. 5, Pec. unita, Brongt. ; Old Mills Pit (Farrington Series). — 

 This small specimen differs from the last in the segments being slightly more 

 elliptical, the specimen being in fact the Goniopteris elliptica, Fontaine and 

 White.* 



PI. XXIV. fig. 4, Pec. unita, Brongt. ; Camerton. — This would perhaps be 

 regarded by some as Pec. longifolia, Brongt., but I believe it to be the upper- 

 most entire pinnse of Pec. unita. A like view is taken of a similar specimen 

 figured by Weiss in his Foss. Flora d. jilngst. Stk. u. d. Rothl., pi. xii. fig. 5. 



Probably the Pec. lanceolata, Lesqx., should also be referred to Pec. unita as 

 its upper portion. t 



PI. XXIV. fig. 6, Pec. unita, forma emarginata ; Camerton. — This specimen 

 is clearly the Pec. longifolia, Brongt. ( — P. emarginata, Gopp.). J Enlarged draw- 

 ings of the nervation are given at fig. 6a. In comparing this specimen with 

 that given at fig. 4, the differences are not greater than what occur in pinnae 

 situated on different parts of the same frond. 



Figs. 4 and 6 are similar to the specimens Germar has figured as Pec. longi- 

 folia in his Vers. d. Steink. v. Wettin u. Lobejun, fasc. 3, pi. xiii. My fig. 4 

 corresponds to his fig. 2, and my fig. 6 to his figs. 3, 4. 



PI. XXIV. figs. 7, 8, Pec. unita, forma emarginata. Fig. 7 from Eadstock ; 

 fig. 8 from Upper Conygre Pit, Timsbury. — These figures also represent the 

 Stichopteris longifolia, Brongt., sp., of Weiss,§ which is evidently similar to Pec. 

 emarginatus, Gopp., sp., as figured by Bunbury. 



PI. XXIV. fig. 2, Pec. unita, forma emarginata; from Camerton. — This 

 specimen would also be referred, by those who regard Pec. unita and Pec. 

 emarginata or longifolia as distinct species, to the latter plant. 



In regard to the various figures I have given in illustration of the different 

 forms assumed by Pec. unita, if only characteristic specimens of Pec. unita, 

 Brongt. (fig. 3), are dealt with on the one hand, or those characteristic of 

 Pec. longifolia (figs. 2 and 6) on the other hand, one would probably be led to 

 conclude that there were here two very distinct species. When, however, a large 

 series of specimens is examined, these two supposed species are so intimately 

 connected by intermediate forms that I have found myself unable definitely to 

 say where Pec. unita ends and Pec. emarginata begins. I therefore class the 

 latter as a form of Pec. unita. 



* Perm, or Upper Carb. Flora, p. 83, pi. xxx. fig. 1. 



f Pecopteris lanceolata, Lesqx., Coal Flora of Pennsyl., p. 227, pi. xxxix. figs. 9, 10 = Alethopteris 

 lanceolata, Lesqx., Geol. Rep. of Illin., vol. iv. p. 398, pi. xiii. figs. 1-3. 

 \ Hist. d. veget. foss., pi. lxxxiii. fig. 2. 



§ Foss. Flora d. jilngst. Stk. u. d. Rotlil., pis. ix., x. figs. 7, 8. 

 || Quart. Jour. Geol. Soc, vol. ii. p. 86, pi. vi., 1846. 



