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PANDEY and JOHN H. CALLOMON PANDEY, D. K. & Contributions to the Jurassic of Kachchh, Western India. III. The Middle Bathonian ammonite famili� Clydoniceratidae and Perisphinctidae from Pachchham Island 01-IIRENDRA K_ PANDEY and JOHN H. CALLOMON PANDEY, D. K. & CALLOMON, J. H. 1995. The Middle Bathonian ammonite families Clydoniceratidae and Perisphinctidac from Pachchham Island.- Beringcria 16: 125-145, 4 text-figs., S pis.; Wtlrlburg. Abslract. Marine Bathonian sediments of the K.havda Fonnation exposed on Pachchham Island in Kachchh, western India, are over 200m thick. Ammonites have been found at only two levels a few meters apart inthe upper part of the Fonnation, in the Goradongar Yellow Flagstone Member. To the rare Clydoniceras and Bullatimorphites described previously are now added also rare Micromphalites and more abundant Procerites (Gracilisphinctes) arkelli COU.ICNON, a Madagascan species. The faunas of the two levels caiUlot be distinguished and are therefore treated as a single faunal horizon. Its correlation with the type horizon of P. arkelli appears to be exact, and its age is Middle Bathonian, most probably the earlier part corresponding to the Progracilis Zone of Europe. a b1dia, Pachchham, ammonites, Middle Jurassic, Khavda FomJation, Progracilis Zone Addresses of the authors: D. K. PANDEY, Department of Geology, University of Rajasthan, Jaipur 302004, htdia; J. H. CAL.I..OMON, University College London, 20 Gordon Street, London WC I H OAJ, U.K. Introduction ceriles and Gracilisphinctes from Gora Dongar so far undescribed, some collected in January 1992. The present paper deals with the description and illustra­ Bathonian ammonites are very scarce in the Jurassics tion of these ammonites and discusses their age and of Kachchh. During the last decade or so, two frag­ distribution. mentary specimens were first recorded from Kala Dongar ("Black Hills"), and rather more from Gora Dongar ("White "Hills") on Pachchham Island, Biostratigraphy Kachchh, Western India (SINGH, )AJTLY & PANDEY 1982; SINGH, PANDEY & )AJTLY 1983; PANDEY & AGRAWAL 1984a). They belong to the genera Cly­ The Bathonian ammonites to be described here come doniceras BLAKE, Aficromphalites BUCKMAN, Bullati­ from two levels in the Goradongar Flagstone Member morphiU!s BUCKMAN, Procerites SIEMIRADZKI and of the Khavda Formation (FDRSTCH ct al. 1994) (Text­ Grilcilisphinctes BUCKMAN. The specimens of C/y­ fig. 2). The beds consist of 40-50 m of prominently doniceras and Bullatimorphiles have already been yellowish fossiliferous silty to fine sandy marls and described (PANDEY & AGRAWAL 1984b; PANDEY & micritcs with intercalated slabs of sometimes golden WESTERMANN 1988). Out of the rest, only the two oolitic calcarenite. They are exposed in patches all small, fragment;:�ry and poorly preserved specimens along the hills of the Gora Dongar range (Text-fig_ 1). from Kala Dongar, one each of Micromphalites and At Sadhara, at the south-eastern end, the ammonites Graci/isphinctes. have so far been described (JAITLY & are confined to two levels 2·3 m apart in the upper part SINGH 1984). But there are now numerous well-pre­ of the Member (FORSICH et aL 1994: 124, beds served specimens, 35 in all, of Micromphalites, Pro- E2d, h). 126 D. K. PANDEY& J. H. CALLOMON R A N N 0 F� K A C H c· H . H PACH HAMls BElA Is KHADIR Is Khavda � Q 0 GORA DONGAR Sadhara • Bhuj 80 KB KUNWAR BET KD KALA DONGAR KD GO GORA DONGAR Rb Ralmalro Bet Kh Khavda 1 Pachhmaipir 2 Madai Bet GD 3 Khari 4 Sadhara Sea Bengal Text-fig. I. Map showing localities referred to in the text. Outcrops of Mesozoic rocks as inliers in younger cover ringed in outline The lower level has yielded Clydoniceras triangu­ cal local specimens of Gracilisphinctes are kept in the lare PANDEY & AGRAWAL, Bullatimorphites (s. s.) n. temple there (see Plate 5 below), but the precise level sp. A PANDEY & WESTERMANN (1988) and Graci/­ from which they come is not yet known. lisphinctes. The ammonites from the upper level in­ clude Clydoniceras pachchhamense PANDEY & AGRAWAL also previously described, and Microm­ Measurements and storage phalites (Ciydomphalites) cf clydocrompha/us ARKELL and Gracilisphinctes arkel/i COLLIGNON Measurements of specimens are in millimetres, gener­ described here. The next higher level in Gora Dongar to have ally taken along the maximum diameter of the pre­ served shell unless otherwise mentioned. Relative yielded ammonites - Macrocephalites sp. cf. or aff. proportions (lower-case letters) are given as fractions madagascariensis - is the Raimctlro Limestone (Text­ of the diameters. The following conventional abbrevia­ fig. 2), 35 m higher. The Goradongar Flagstone Member is also typically tions have been used: developed throughout the Kala Dongar, and good D: diameter of the shell. exposures may be seen below the summit around H: height of the last whorl measured along the shell Pachhmaipir, the highest point on the northerly scarp diameter; h =HID. of the range overlooking the Rann and, at Bhabia Hill, W: thickness (width) of the whorl where the height the highest point on Pachchham Island (468 m). Typi- has been measured; w = WID. Middle Bathonian anunonite from Kachchh 127 U: diameter of the umbilicus measured along the GORA DONGAR shell diameter; u U/D. = SADHARA Specimens with numbers PO/ ../ .. arc lodged in the Palaeontological Laboratory, Department of Geology, I TERTIARIES I Banaras Hindu University, Varanasi 221005, India, ��o�r�lovJ!_n • LOWER CHARI FM U IMA '" N whereas those with numbers RUCI993J ... are pre- 250 p.f!r�ho!!!_an " served in the Department of Geology, University of GADAPUTA SANDSTONE Rajasthan, Jaipur 302004, India. - - - MEMBER II!GORAOONGAR 200 Middle Bathonian YELLOW Systematic descriptions FLAGSTONE MEMBER - - - z 0 Superfamily HaJlloccrataccac ZITTEL 1884 � 150 MIDDLE ::11 a: Family Clydoniccratidac S. BucKMAN 192 4 SANDSTONE 0 IL MEMBER Genus Clydoniceras BLAKE 1905 c( c 100 > c( Type species. J. SowERBY 1813, :J: Ammonites discus "" Lower Cornbrash, Discus Zone, England. LOWER YELLOW FLAGSTONE Clydoniceras sp. indet. MEMBER 0 l'l. I, Fig. I EOMIODON . RED Material. One small specimen (PG/172/25b), originally allached to the SANDSTONE Micromphalites described below. MEMBER - - - - - Horizon and locality. From the higher level in the Goradongar Flag­ 0 Uppe< � SADHARA CORAL slone Member, Khavda Fon11alion, north-east of Sadhara. Bajocian LIMESTONE MEMBER I t I Dimensions. D WIH Text-fig. 2. Sununary of the stratigraphy of the K.havda Formation, Pachchhmn Island, as exemplifiedby the sections PG/172n5b 12.9: 0.46 0.32 0.24 0.70 at the eastern end of Gora Dongar, at Sadhara (after FORS!CH Description. Incomplete small phragmoconc, com­ et al. 1994). l11e Raimalro Limstonc is the equivalent of the pressed and moderately cvolute with subovate whorl­ Patchmn Limestones at Jumara on the Kachchh Mainland, which are there dated by ammonites. section; maximum inflation at dorsal-third of the whorl-height. Flanks feebly arched, sloping towards Genus BUCKMAN 1923 the periphery to form a narrow venter. Umbilical wall Micromphalites rather steep, making a rounded obtuse angle with the flank. Ribs fine, concave forwards, confined to the Type species. Ammonites micromphalus PHILLIPS outer, ventral-third of the whorl. Sutures well pre­ 1871; Middle Bathonian, Progracilis Zone, England. served and typical of Clydoniceras. Subgenus Ciydomphalites ARKELL 1952 Remarks. The specimen compares quite well with the figures of the NW-Gerrnan specimens identified as Type species. Micromphalites clydocromphalus Clydoniceras discus planum DE GROSSOUVRE ARKELL (1952), Middle Bathonian, central Arabia. (WESTERMANN 1958: 57, pl. 12, figs. 5-6; pl. 13, figs. 1-2) in many of the diagnostic characters. But since it Micromphalites (Ciydomphalites) cf. clydocromphalus is merely a nucleus, no closer assignment can be made. ARKELL 1952 It serves merely to confirm the range of the genus as extending downwards well into the Middle Bathonian. 1'1. !,Figs. 2,3 128 D. K. PANDEY&J. H. CALLOMON cf. 1952 Micromphalite! (Clydomphalites) clydocromphaltu Clydoniceraf (s. s.) discus (J. Sow.) (ARKELL 1951: ARKELL:287, pl. 26, figs. I, 7, 9;pl. 28, fig. 12; Text-fig. 33, pl. 2, figs. 2a, b, c) differs in having an O:\.'}'COnic 9. cf? 1958 Micromphnlites saint..oursi COUJGNON: pl. 9, fig. 45 whorl-section without shouldered venter. It is a macro­ (l)'p<). conch, but its microconch C. (Delecticeras) is even more distinct at the diameters under consideration Material. Two poorly preservedspec imens (PGII72/2Sa &. PGI240/8). here, being more involute, compressed and densely 1be fonncr wu found associated with the Clydoflicera.r sp. indet. describedabove. ribbed. llorizon and locality. Fromthe higher level in the Goradongar Flag­ �one Mm1ber,north-east ofKhari andSadhara. Micromphalites (Ciydomphalites) sp. indet. Dimensions. Pl. I, Figs. 4,5 D WIH Material. Two fragmentary&peein'lens (P0/129/4 & PG/239/10). PGI172125a 50: 0.52 0.11 PG/240/8 41: 0.55 0.22 0.12 0.40 llorizon and locality. From the higher level in the Goradongar Flag­ stone Member, north ofKhari and WNW ofSadhara. Description. Phragmocone discoidal, involute and with Description. Both specimens consists only of quarter­ keeled venter; maximum inflation at the umbilical whorls of phragmocone. Compressed, keeled, fastigate shoulder. The surface on the inner whorls is orna­ whorl-section with maximum thickness at the umbili­ mented with broadly rounded primaries dividing into cal shoulder; umbilicus small, its walls vertical with two to three falcoid secondaries, but with maturity acutely rounded umbilical edge. Lateral surfaces more these gradually become restricted to the outer third of or less flat, sloping very gently towards the venter to the whorl-side leaving the umbilical region smooth. form shoulders at the ventro-lateral edges, with a nar­ The secondaries terminate in nodes giving the appear­ row keel; ornamented with faint and blunt falcoid ribs ance of a slightly square-shouldered venter. Keel ser­ the primaries rectiradiate, occasionally bifurcating a� rated with very fine transverse thread-like lineations. mid-height and then turning backward · with slight .. Remarks. The general sculpture of the shell, i.
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