Plant fossils from Dubrajpur Formation, Bihar and their significance in stratigraphy Ja;'Jsri Banerji Banerji. Jayasri 1990. I'lanl fossils frllm J)ubralPur Form:llion. Bihar and their significance in stratigrap!l\' 11/: J11I1. K. 1'. &. Ti\yari, R. ~. (cds)-I'roc. S)'IlIjJ. ·1·i.,las il/ I/ldiall l>aICl<!obo!aIly'. J>a/(,l<!obulallisl 38 122·1.30. -n1e paper deab \\'ilh the plant fossils of J)ubrajpur Formation exp()~ed at Khatangi Hill in the Raim:lhal Basin. Bihar 11lC assemhlage is dllmin;lled Iw (\·cacloplwleo. lhllug!l pleridllp!l\'les are quile frequent. Cllnifers :Ire poorl~' represented. llH.: genera UllychiojJsis, Clem·s. Taelliupleris and I'agiuphyllll!ll art' recllrded for the first time. In \'iew of the presel1l finding the age llf th" Khatangi scdimen!' is discussed. The dominance of (Ycldllpll\leS and pllor repre,entati()[l of cllnifers inclicale subtropical to tmpical climate pre\'ailing :It thal lime. Key-words-I\\egafossih. Pteridop!l\les. C\·cadophqes. Conifers. J)uhr'ljpur l'urmation. L'pper Jurassic (India 1. .!ayasri IJallerji. 15lrbal Sal'" I Ii/Slilllll! of I'alaeobulall.l', 'H l'llil'er"il)' Road, !.IICRIIO/1" 116 (J07, Illdia ~~T ~ .~-~ 'lR'{-3N~ ~ ~ firw if ll' ,PIT fiHI'4"lll1 if ;;mm ~ ~ ~~ ~ ~ ~tor-~ 'ft~!I QR'IT~"Il'f ~ ~ ~ if if l3lCflfi if 3RT<lfuf <liT 'i'f'I'R lJ1lT I eft m'hI$<!1 ~ QR'IT~'l ~ ~ ~i1T qri! ~ it 3!fU<!> 1f&rr it fI:R<'t ?, <ilt<$sl'hlt<!l qrW <tit fr,1 3f?l mr if rmt 'Til tl ~ qn~ ~ ~ ~ ~ ~ ~3lIftmf, ilf.m, i'tf';f~ 'lT11<li it om: 3!f'llfufu<r <tit 1Ji I ~$"f QR'ITM~<$ ~ ~ ~ ~ 1i1$J;shls<!l'~'1 ~ ~ WHR q< ~ <tit <tit <tit 1Ji I <tit ,PIT <tit 3f?l 1f&rr 'ft '$ ~ ~ ~ '34161JI<Ii[leHlm it ;j61JI<MceHlm <liT <Wra \'iti1T I OLDHAl'vl (1863 in: Oldham & Morris, 1963) first Ptilophyll1l1l1 aClltijolium, Nilssonia princeps, recognised Dubrajpur beds as a distinct horizon and Macrolaeniopleris lata and Williamsonia sp. of early named it after the \'iJlage Dubrajpur in the Rajm3hal Middle Jurassic age. Sen Gupta (1984, 1985) carried Hills. Ball (1877) mapped this area and reported out e\.'tensive work on Khatangi Hill section as well Ptilophyllllm fronds from Dubrajpur beds. Later, as the designated type section of Dubrajpur Sri vasta va (19<>8), Sah ( 196<» and Sen Gupta ( 1988) Formation at Sarwan Pahar near Dubrajpur Village. recorded various fossil assemblages from Dubrajpur According to him, basal zone-A of Sah and Shah Forrnation exposed at Khatangi Hill near Kharikasol (1974), i.e., Glossopteris- Vertebraria assemblage, Village, Rajmahal Hills, Bihar (see Table 1) and belongs to the Barakar Formation and the upper proposed \'arious ages for the Ptilophyllllm-bearing 7.one-B comprising Ptilophyl!um-Gleichenites beds of Dubrajpur Formation assemblage belongs to Dubrajpur Formation (Lower Sah and Shah (1974) made twO biozones within Jurassic). Sukh-Dev (1988) assessed an Early Dubrajpu'r Formation The basal zone-A, comprising Cretaceous age for the latter assemblage. Tiwari et Glossopleris communis, G. ampla, G. retlJera, G al (1983) rccogni zed six paJynoassemblage zones parallela and Vertebraria indica of Upper Permian from the subsurface sequence of Dubrajpur affinity and the upper zone-B consisting of Formation as well as Intenrappean beds. They dated NJarattiopsis macrocalpa, Gleicheniles gleichenoides, palynoassembl3ge zones A·C as Carnian-Norian, and l22 l3ANER.lI-I'l.AJ\lT FOSSIlS FI~OM DU13RA.lPliR FORI"lATlON 123 zones D-F as Late Jurassic/Early Cretaceous, Singh Cleichenites gleichenoides (Oldham & Morris) and Venkatachala (1988) reassigned zones D-F to be Seward & Sahni 1920 Early Cretaceous. Genus- Culcitites Appert 1973 The present investigations are based on plant fossils collected from Khatangi Hill. These plant Culcitites madagascariensis Appert 1973< remains are preserved as impressions on greyish­ 196=; ?ThinnJeldia sp., Sah, p 219, pI. 1, fig. 3. white shales. All the specimens have been deposited 1965 jlJicrophJilopteris sp., Sah, p 219, pL 1, fig. 5. at the Birbal Sahni Institute of Palaeobotanv ivluseum. 1988 ThirlnJeldia kbatangiensis, Sen Gupta, p. 75, pL 12, fjg. 32; pI. 15, fig. 40; text-fig. 17 (for details DESCRIPTION see Banerji, 1988) Filicales Unclassified ferns Genus- Gleichenites Goeppert 1836 Genus- Onychtopsts Yokoyama 1889 Cleichenites gleichenoides (Oldhan, & l'vlorris") Onycbiopsis Sp. Seward & Sahni 1920 PI 1, figs 2, 3; Text-fig. JA PI. 1, fig. 1 Descnption-Fronds probably tripinnate, best Remarks-In gross morphological features, the available specimen about 2.5 em in length. Ultimate present specimens are similar to those of pinnae sub-oppositely attached at an angle of 60°- Table I-Plant fossil assemblages recorded by different authors from Dubrajpur Formation at Khatangi Hill Srivastava, 19')8 Sah, 1965 Sen Gupta, 1988 Present assemblage FILlCAlES: FILICALES: FILICALES: FILICALES: Gleicheniles sp. Gleicheniles gleichenoides Gleicbeniles gleicbenoides Gleicbeniles gleichenoides Maralliopsis sp. (Oldham & Morris! (Oldham & Morris) (Oidium & Morris! Seward & Sahni Seward & Sahni Seward & Sahni Cutcililes madagascariensis Appen UNClASSIFIED FERNS: UNCLASSIFIED FERNS UNClASSIFIED FERNS: UNCLA.c;SI FI ED FERNS: Cladophlebis sp. Cladopbtebis indica Cladophlebis indica Cladopblebis indica Sphenopleris sp. (Oldham & JVlorris) (Oldham & Morris) (Oldham & Morris) Pecopleris sp Sahni & Rao Sahni & Rao Sahni & Rao Cladophlebis sp. Onychiopsis sp. Microphyllopleris sp. CYCADALES: PTERIDOSPERMAlES: PTERIDOSPERNlAlES Nitssonia sp. ?Thinnjeldia sp. 7binnjeldia kbalangiensis sp. nov. BENNETTITAlES BENNE1TITAI.ES: OENNETTITALES: BENNETTITALES: Olozamiles sp. Plerophyllllm sp. Plilophylillm aculijolium Plilopbyllum cUlcbense Williamsonia sp. Morris Morris Plilopbyllum aculijolillll1 Pleropbyllum fissum Plilopbyllllm aculijolium Feistmantel Williamsonia sp. Plerophyllllm dislans Morris Plerophyllurn sp. d. P. jooleanull1 Feistmantel CYCADALES: CYCADALES: CYCADALES: Nilssonia princeps Taeniopleris crenala Nilssonia sp. (Oldham & Morris) McClelland Glenis rajmabatensis n. sp. Nitssonia sp. Taeniopleris sp. ef. Macrolaeniopleris lala T oldbamii Bose & Banerji (Oldham & Morris) Taeniopleris sp. Sahni CONIFERALES: CONIFERALES Elalocladus conjerla Pagiopbyllum sp. (Oldham & Morris! Sahni 124 THE PALAEOBOTANIST 70°, linear to lanceolate in shape, largest ultimate Cladophleb is indica -Die tyozami tes indic us pinna 1 em long and 2.5 mm broad. Pinnule-lobing assemblage zone of Middle to Upper Jurassic and towards base complete but towards distal end lobing absent in Ptilophyllum acutiJolium-Gleichenites incomplete at places. Pinnules oblanceolate to gleichenoides zone of KhaLangi Hill. elliptical in shape, measuring 1.5-2 x 1-1.5 mm, Ptilophyllum acutiJulium Morris 1840 margin entire, apex subacute to obtuse, attached by broad decurrent base. Venation mostly PI. 1, fig. 9 inconspicuous. Proximal pinnules with forked or Remarks-A few specimens resembling P. unforked veins; rest, at places, showing keeled acutiJolium are present in the collections. midvein appearing to be fertile. Genus- Williamsonia Carruthers 1870 Remarks-Five frond fragments have been recovered but their fertile nature is uncertain. The Williamsonia sr. specimens are comparable with Onychiopsis PI. I, figs 5, 7 elongata (Geyler) Yokoyama (1889, pI. 12, fig. 10) in size and shape of sterile pinnules. Sukh-Dev (1970) Description-Flower large, incomplete, about considered 0 elongata and 0 paradoxus Bose & 10-14 em in length and 7 em in width; base of the Sukh-Dev 1959 as junior synonyms of 0 psilotoides flower probably rhomboidal, gradually tapering (Stokes & Webb) Ward but Kimura and Aiba ( 1986) towards apex, bracts numerous, more than 12 in maintain 0 elongata as the type species of this number, 5-6 mm broad, surface of bracts striate, genus. prOXimal portion of bracts hairless but distal portion hairy; hairs up to 8 mm long. Genus- Cladophlebis Brongnian 1849 Comparison-Only two specimens are found, Cladophlebis indica (Oldham & Morris) Sahni & Rao one (PI. 1, fig. 5) shOWing proximal part with 1933 hairless bracts and the other (PI. 1, fig. 7) shOWing PI. 1, fig. 4 distal part of bracts with profuse hairs. Although both the specimens are described here as Comparison-Cladophlebis indica is common in Williamsonia sp., there is a possibility of existence the assemblage. These forms are similar to the of twO different species. sterile frond of (Oldham Morris) Todites indicus & In their large size, the present specimens Bose & Sah described from various other localities of resemble Williamsonia indica Seward 1917 and W Rajmahal Basin. But due to lack of fertile fronds from sahnii Gupta 1943. But the specimen with profuse this locality, they are being placed provisionally hairy bracts resembles W. sahnii and the other one under (Oldham & Morris) Sahni Cladophlebis indica compares with W. indica having hairless bracts. & Rao 1933. Bennettitales Genus- Pterophyllum Brongnian 1828 Genus- Ptilophyllum Morris 1840 Pterophyllum distans Morris 1863 PI. fig. 10 Ptilophyllum cutchense Morris 1840 1, PI. 1, fig. 6 Comparison-The specimen of Pterophyllum Remarks-According to Sen Gupta (1988, p. distans from Khatangi Hill, except for smaller pinnae 103) Ptilophyllum Cll tchense Morris is restricted to is similar to those of the same species from Kutch PLATE 1 -- 1. Gte/cben/tes gte/cheno/des (Oldham & Morris) Seward & Sahni, 36250. x 1 a fragmem of frond bearing small deltoid pinnules, Specimen 6. Ptilophyllum culchense Morris. shOWing overlapping pinnate no. BSIP 36244, x I leaves. Specimen no. BSIP 36262