1996-97 - Birbal Sahni Institute of Palaeobotany

BSIP
related to some of the glossopterids. Ovule-bearing Dictyopteridium-type fructifications,
found attached to the midrib of the leaf, are dorsi ventral, foliar structures that bore
ovule only on the adaxial surface. Cross-sections of the petrified material have shown
that due to revolute nature of the leaf lamina, the ovule-bearing surface was partially
covered. None of these characters support the inclusion of this group of plants under
the Pteridosperms sensu-stricto. Sum total of vegetative and fertile organs ranks this
group as an independent order, Dictyopteridiumales in the Class Glossopteridopsida.
This group was a phyllosperm, and not a caulosperm.
A major overview of the problems related to Permian-Triassic Boundary in
the global context was prepared. The major stratigraphic divisions of the Phanerozoic
are based on mass extinction events. These divisions are called as systems and the
boundaries between them are more often based on the concept of biotic crisis, than on
lithology. In continuous sequences it is usually possible to clearly draw the system
boundaries, but in cases of global stratigraphic gaps, as between the Permian and
Triassic, the placement of the system boundary becomes a difficult task. This overview
discusses and analyses available information of the Permian-Triassic Boundary interval
both in the marine and continental sediments and brings out gaps in informations as far
as continental strata are concerned.
Programme 2.6 : Pattern of evolving palynofloras through Gondwana
Sequence in Damodar Graben
Vijaya
In the Domra sub-basin in Bore hole PGD-6 (501.65-229.60 m thick strata),
the upper part of Panchet Formation has yielded Murosporaflorida palynozone, which
directly overlies the Lundbladispora- Verrucosisporites palynozone in Panchet
Formation. Subsequently, in Rajmahal Formation, the Intertrappean sediments have
yielded Cicatricosisporites australiensis palynozone. Here the Murospora florida­
Cicatricosisporites australiensis palynozones suggest the Jurassic-Cretaceous transition
at the Panchet-Rajmahal formational boundary level (501.65 m depth) in Bore hole
PGD-6
Visited eastern most part ofPanagarh-Deocha, West Bengal and Rajmahal Basin
for the collection of rock samples for palynological studies. Also visited Geological
Survey of India, Calcutta for scientific discussions and consultation of literature.
Programme 2.7 : Composition, relationship and age of the megafossil flora
of Rajmahal Formation
Jayasri
Banerji
Megafossil assemblage of fossiliferous Intertrappean bed near Balidih in
Rajmahal Basin was studied. It includes - Equisetites rajmahalensis, Phyllopteroides
laevis, Pachypteris sp. cf. P. indica, Thinnfeldia indica, Ptilophyllum acutifolium, P
cutchense, Anomozamites sp. cf. A.jissus, Taeniopteris sp. cf. T spatulata, Elatocludus
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