ISSN 0375-1511 Rec. zool. Surv. India: 113(Part-3): 137-144,2013 ON SOME MEGAINVERTEBRATE (MOLLUSCA, ECHINODERMATA AND BRACHIOPODA) FOSSILS FROM BAGH BEDS, MADHYA PRADESH M. K. NAIK Zoological Survey of India, M-Block New Alipore, Kolkata-700053 INTRODUCTION echinoids, brachiopods, gastropods and Marine Cretaceous deposits have been lamellibranch material. Fourteau (1918) assigned recorded in large part of the Extra-peninsular belt upper Albian age of the beds on the basis of of the Indian Subcontinent. A condensed recovered echinoid fauna of the beds. Mukherjee sequence form of this type of deposit has also been (1935,1936,1938) opined that the Bagh beds range recognised in the Narmada Valley of Central in age from the Cenomanian to the upper India. Less thick marine Cretaceous deposits Senonian. Spath (1927-33) was of opinion that the came up in the vicinity of Bagh, a township in Bagh ammonites belong to Turonian age. Dhar District of Madhya Pradesh, on the western Chiplonkar (1939) on the basis of bivalves of the portion of the Narmada Valley. The Bagh beds, in beds assigned an age from Albian to Senonian, fact stretch from Rajpipla about 35 miles ( 56 km.) with Cenomanian as the more dominant aspect. west of Gulf of Cambay in Gujarat eastwards as Roychaudhur & Sastri (1962) proposed a far as Barwaha, about 240 miles ( 386 km.) from stratigraphic classification of the Bagh beds. the coast of Gulf (Pascoe,1959). The Bagh beds Dassarma & Sinha (1966) recorded shark teeth though contain comparatively thin sedimentary and other marine animal forms of Cretaceous strata but possess substantive diversity of faunal affinity in the Nimar Sandstone horizon of the elements. Eventually, the beds have long been an Bagh beds. Pal (1970) made a review of the fossil important focus of attention of the geologists and forms explored from the Bagh beds of the Man palaeontologists for their rich fossil faunal river section. Chiplonkar & Badve (1973) made martial. Dangerfield (1818) pioneered the detailed taxonomic assessment of an extensive collection geological investigation on a regional scale of the of bivalve molluscs of Bagh beds including Bagh beds. Later, Carter (1854), Keatinge (1856) several new forms. This fauna demonstrated an and Oldham (1858) commented upon the age of affinity to the fauna of the Mediterranean the Formations in Bagh beds. Carter (loc. cit.) palaeozoogeographic province and assigned an assigned a Neocomian age of the Formation but age from Cenomanian to Turonian. Subsequently, Oldham (loc. cit.) had certain disagreement with Chiplonkar & Badve (1976) and Chiplonkar & the view of Carter. Keatinge (loc. cit.) however, Ghare (1977) worked out the ammonoid fossils, assigned a general Cretaceous age for the and trace fossils and palaeoecological conditions fossiliferous beds. Bose (1884) assigned an Albian of the Bagh beds. In the background of the toTuronian age for the nodular limestones on the potentiality of Bagh beds as a fossil storehouse; it basis of recovered molluscs and echinoderm was thought that a lot more interesting forms material, and a Campanian to Maestrichtian age could be recovered from the area. Hence, the field for coralline limestone on the basis of recovered works were carried out recently by the ZSI in this 138 Rec. zool. Surv. India Table 1 : Stratigraphic succession of Bagh beds: Development of concepts Stratigraphic Units Stratigraphic Units (after Rode & Chiplonkar, 1935) (after Chiplonkar, Badve & Ghare1975 Upper coralline limestone Upper coralline limestone with oyster bed at top Deola and Chirakhan Marl Upper Inoceramus bed Deola & Chirakhan Marl with Hemiaster Lower coralline limestone (c. 1.0 m.) Lower Coralline Limestone Nodular limestone Lower Inoceramus bed Nodular Limestone Nimar Sandstone Astarte-Turritella bed Oyster bed with shark teeth Trace fossil horizon Lower portion of Nimar sandstone with oyester bed area for exploration of the nature of the fossil Bagh cave over an interval of about 15 meter faunal content, especially the megainvertebrats. above the lowest oyster-bearing horizon. The collection made during the field works has Subsequently, gradual decline in oyster shells and been worked out and the result of the study is appearance of Astrate-shells give rise to Astrate­ presented here in the background of the bed. Sandstone horizon succeeds in a gradual lithostratigraphy of the Bagh beds. manner into the Nodular limestone. Astrate-bed bears representatives of Turritella spp. It has been STRATIGRAPHY shown by Chiplonkar & Badve (1980) that setting The Bagh beds comprised depositional strata of immature stages was induced by dense of relatively small depth but contain population of sessile epifauna like, Ostrea. Other heterogeneous composition. This heterogeneous species of oysters also flourished well. Infrequent nature within short depth point out to rapidly occurrences of oysters shells were recorded in the changing depositional conditions. Accession and lower and upper coralline horizons. Near the top recession of the transgressing waters of the of the upper coralline limestone layer dense marine regime were the frequent occurrences and population of oysters further point out to another the phenomena influenced substantially over the distinct oyster bed. The two Inoceramus bearing times which thrived in the Narmada basin during horizons had similar lithic characteristics, viz, the depositional phases. Rode & Chiplonkar marly limestone, but were well separated from (1935) proposed a stratigraphical sequence which one another (Chiplonkar & Badve, 1976). was modified later on by Chiplonkar et aI., (1973) It has been apparent that the Bagh Formation with incorporation of some more details viz., contains at least two major depositional hiatuses. Oyester beds, Inoceramus beds, Astarte-Turritella Kennedyet.al. (2003) assigned a late Turonian age beds, etc., (see Table-l). to the Bagh Formation on the basis of findings of Stratigraphically, the layer containing ammonite from the upper Nodular limestone, oyesters becomes the lowest horizon, and which several kilometres to the west of Man River is encountered in the ferrugenous shaly band of section. While on the basis of findings of the Nimar sandstone. It ranges in thickness from inoceramid bivalves Gangopadhyay & Bardhan about 0.5 to 1.0 meter and is situated slightly (2000) claimed to support a Conaician age. As the above the local base of the section, or otherwise late Turonian ammonite dating comes from high the actual base of the Nimar sandstone which is in the succession, it is perceived that the lower not exposed. Another oyester bed of about 1.5 beds in the Formation might extend down to the meter thickness was recognised to the west of Cenomanian. NAIK : On Some Megainvertebrate (Mollusca, Echinodermata and Brachiopoda) 139 SYSTEMATIC PALAEONTOLOGY Material: 1 example Phylum MOLLUSCA Locality: Chakrud, Thana-Manawar, District: Class CEPHALOPODA Order AMMONOIDEA Dhar,M.P. Suborder AMMONITINA Geological age: Cretaceous. Family ASPIDOCERATIDAE Zittle 1895 Family: PLACENTIRCERATIDAE Hyath, 1900 Genus Paraspideceras Spath, 1925 1. Genus Placenticerus Minitoi, 1. Paraspideceras sp. Diagnosis: Very involute, with slightly convex Diagnosis: Whorls very depressed, coronate sides and very narrow venter with faith falcoid and spinous from early stage, outer row of spines ribs umbilical tubercles of early whorls move upto more or less clavate, inner row recessive or absent. mid sides on lateral whorls normally with lower Material: 1 example and fine upper ventra-lateral clavi, ornamental weakens in adult and last whorls may be smooth Locality: Awlda, (Seetapur) village, Thana­ and with narrowly rounded Venrer. Suture with Manawar, District: Dhar, M.P. many auxiliaries. Geological age: Cretaceous. Material: 12 examples Genus Peltoecras Waagen, 1871 Locality: Bariha village, Thana-Manawar, 2.Peltoceras sp. District: Dhar, M.P. Diagnosis: Evolute whorls hardly overlapping Geological age: Cretaceous. ribs strong bifurcating and trifurcating on Genus Placenticerus Kaffrorium ventral margin. Venter nearly flat, outer row with 2 rows of massive lateral, tubercles, outer row 2. Placenticerus sp. developing first. Diagnosis : Rare kind of ornament that is seldom seen because it is apparently confined to Material: 1 example the structure of the inner shell layers occurs on all Locality: Awlda, (Seetapur) village, Thana­ of the whorl sides, chiefly in oxycones, the consist Manawar, District: Dhar, M.P. of a band of delicate, forwardly directed chevrons, Geological age: Cretaceous. standing in scarcely perceptible relief and thus generally visible only by low angle lighting. It has Genus Metapeltoceras Spath, 1931 been figured in some cretaceous pseudocertites 3. Metapeltoceras sp. and main species is Placenticeras kaffrorium. Diagnosis: Differs from Peltoceras in Radial strips have been noticed other bolder size developing inner lateral tubercles before outer. pattern occur in Palaeozoic Straight. Material: 1 example Material: 35 examples Locality: Chakrud, Thana-Manawar, District: Locality: Chakrud, Thana-Manawar, District: Dhar,M.P. Dhar,M.P. Geological age: Cretaceous. Geological age: Cretaceous. Genus Peltomorphites Buckman, 1925 Class GASTROPODA Order ARCHAEOGASTROPODA 4. Peltomorphites sp. Family PLETHOSPIRIDAE Diagnosis: Inner whorls as in Peltocerotides; Genus Gyrodoma Etheridge, 1898 outer whorls became tritubarculate and spinous 1. Gyrodoma sp. with ventral as well as lateral tubercles . Comprises" eugenii group" Diagnosis: