The Palaeobotanisr, 32(1): 1-19, 1984.
MICROBIOTA FROM THE KUSHALGARH FORMATION, DELHI SUPERGROUP, INDIA
J. MANDAL*, P. K. MAITHY*, G. BARMAN** & K. K. VERMA** *Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow 226 007, India **Palaeontological Laboratory, Western Circle, Geological Survey of India, Jaipur 302 001, India
ABSTRACT Well-preserved and diverse microfossils are described for the first time from the Kushalgarh Formation of Ajabgarh Group around Baraud Village in Alwar District, Rajasthan. The assemblage comprises 10 genera and 17 species belonging to filamen tous and coccoid blue-green algae, of which two genera and 10 species are new. The new forms are Myxoeoecoides eompaetus sp. nov., Palaeolyngbya distinetiea sp. nov., P. elongata sp. nov., P. baraudensis sp. nov., Palaeoseytonema indica sp. nov., P. intermingla sp. nov., P. misrae sp. nov., Choshia bilureata gen. et sp. nov., Primorivularia robusta sp. nov. and Vesieophyeus problematieus gen. et sp. nov. Morphological features and the size range of taxa suggest procaryotic nature of the assemblage. Coccoid forms are aggregated in colonies and dominated by filamentous forms. Baraud assemblage con tains hormogonia, heterocysts, false branching and the most significant is the record of true branching showing Stigonematalean affinity. The composition of the micro flora suggests that the rocks of D~lhiSupergroup are equivalent to Vindhyans. This is also supported by the radiometric dates. Key-words - Choshia, Vesieophyeus, Cyanophyceae, Kushalgarh Formation, Precam brian (India).
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This assem Maithy and Shukla (1977), Maithy and blage consists mostly of cryptarchs and a Mandai (1983), Maithy and Gupta (1983), few blue-green algae. 2 THE PALAEOBOTANIST There is no previous microfossil record rocks of Delhi Supergroup are concealed from Delhi Supergroup except a report under the alluvium and are found in the form by Dutt and Shrivastava (1975) from Alwar of isolated p~tches.The rocks lie above Group, Gurgaon District. They reported the gneisses or the Aravallis or the Gwaliors Tasmanites other than triletes, monoletes, or the Raialos with a great unconformity septate spore, acritarchs and hystricho and in turn overlain unconformably by spheres. From the illustrations of Dutt the Vindhyans. Lithologically, the rocks and Shrivastava (1975) it appear that the consist essentially of quartzites, mica schists, assemblage consists of only acritarchs be limestones and calcium chloride gneisses. longing to Sphaeromorphitae and Netro The entire succession shows extensive fold morphitae except Tasmanites. Stromatolites ing, faulting and is aff<:cted by igneous have recently been reported by Verma and intrusions in the form of pegmatites, granites Barman (1980) and Negi and Ravindra and epidiorites. (1980) from the Kushalgarh Formation Geology of the area - The microfossil near the village Baraud. The forms are bearing locality lies on the western flank Baicalia baicalica (Maslov) Krylov, Collenia of the north-south trending hill (Text-fig. I), columnaJ'is Fenton & Fenton, Kussiella kusien abou t a kilo meter to the east of Baraud Village sis Krylov and Jacutophyton Shapovalova. (27°54': 76°23', Survey of India toposheet The investigation of microbiota in the area no. 54 A/5), Alwar District, Rajasthan. was taken up due to (i) occurrence of The village is located on Alwar-Behror diverse stromatolite, (ii) absence of micro State Highway at 7th km from Behror which fossil report from this rock sequence, and is locally known as 'Midway' and is (iii) to correlate this thick and widespread situated on National Highway No.8, half sequence of rocks with other areas and way between Delhi and Jaipur. The area particularly fixing the stratigraphical position which is situated on the road side is approach of Delhi Supergroup in relation to the able round the year as it is free from any Vindhyan Supergroup. vegetation. The rock formations which In all, 27 samples from a section belonging occur III this area belong to the Ajabgarh to the Kushalgarh Formation were collected. Group' of the Delhi Supergroup (Precam Out of which only one siliceous dolomite brian). Of the Delhi Supergroup, the older yielded excellently preserved biota. Perma Rajalo and Alwar groups are missing in nent slides were prepared with polyvenyl this area and the sequence commences alcohol and D.P.X. mountant. Observations directly with the Kushalgarh Formation were made using oil imersion objective in of the Ajabgarh Group. As such, the a Leitz Dialux - 20 microscope. Long stratigraphical succession of the area stands filaments were photographed in several as shown in Table 1. shots at different focal depths. These The Kushalgarh Formation comprises a photographs were superimposed to get sequence of marble beds (100 m in exposed the complete structure of filament. section) intercalated with 3 to 5 cm thick The present paper deals with the syste bands of shale and chert. Bioherms of matic description of the microbiota re stromatolites are seen to have developed covered for the first time from Ajabgarh towards the top of this formation. The Group. All the figured specimens are stromatolite forms include mostly of Baicalia housed in the Museum of Birbal Sahni baicalica (Maslov) Krylov, Collenia colum Institute of Palaeobotany. naris Fenton & Fenton, Jacutophyton Shapo valova and -Kussiella kusiensis Krylov (Verma GEOLOGY & Barman, 1980). The stromatolites, in general, are made up of milky white chert. General Geology - Delhi Supergroup ex The microfossils reported in this paper are tends along the main axis of folding of the from a thin chert band lying between Aravalli mountains and is named after marble beds, a few metres below the the city - Delhi and has a very wide stromatolite bearing horizon in the upper geographical distribution from near Delhi part of the Kushalgarh Formation (Text in the north, through Ajmer and Mewar fig. 1). to Idar and Palanpur in the South (Krishna n Age of the rocks - The geological span 1982). In the north (Gupta, 1977) the, of the deposition of Delhi Supergroup rocks MANDAL el 111.- MfCROBIOTA FROM THE KUSHALGARH FORMATION 3 /.:; /4 ( ....~) 1 -" 1 /.~3S4 ~/,.4.. ~ /"4 4 ~.J/6 ,) o 200m ,.:A;. "'"~,..{;.../ I I (A "'""'" 4/ ) 'I ,,' /'4 .135 I ~-rf]- ("/ " 4 4( ~Jj?Y2: 4 A-" I" " '7'-_ .....) I~4. 4/ J I (4 4 "I /4 4 .6 41 14 % "I _"'''\ / ,(1,"1 , .... 4 4 ... _/ 4 4 55 1./ .. /" 4 I ca-'l/" ,," "/" " " "J L~~I" "C-,,-~~,,":J,."'/ '::-"'''''--', -~ ,, , /0 ,," "\ , ' ~...... ~, 14, .a I 4. 4' ,, ., I 16'5" I ,,I ....., )tJ. ~ 6 A/ /~ DE~HI': ,.0. A .0. 6( (: ... ~~BAR~UO...... 14 .0. "/.-" ..!L-I"Lt" I" /'65 "6-_ l, I AAEA OF 4 /6~51:1. i:' \ INVESTIGATtONl " 0 " ,," -~, 4. 4/ .0 4 b:J " 160" r",--" "I " " " 0 /"f - ...." 0/ .Ll..r--l--r--4" " " " M I ' ~ ~ 4C""~"" 6 0/ 'J5 4. ~'i\ ~"r\[/O " "55,, "\ N 9 " " " "J\ 1 6 4. Co 40'.... 4 fJ"q" ""\ ~~""" ,,_ (II ~!4-S;;; 1\ • 7:J.\~A~\,..... 1 INDEX CH[RT } SARISKA BRECCIATEO FORMATION " " QUARTZITE ·lJ ~ MARBLE } 4 ~~ (lIo4PURE) I \A\ .... _4~ '0 ~ " t;., I b b b- ... "', .... ' ....6 6 6 " 1:10\ \6 .0./"'"'1 I \6 b 0 1 I .. "( ',el ' .... I" 4J \ ,,(J ~..../:' "'\ 6 \ 1C..~t;::/ I:" j.' -"i 9-.... ":.:''' \ '\00" / L~::' ~"\~~ TEXT-FlG. 1 - Showing the type locality (after Verma & :!?armao, 1980). TABLE I-STRATIGRAPHICAL SUCCESSION AROUND BARAUD, ALWAR DISTRICT, RAJASTHAN (MODIFIED AFTER NEGI & RAVINDRA, 1980) Vindhyan Supergroup Not developed ------(Acid, basic and ultrabasic intrusives and extrusives)/------rBhakrol Formation Interbedded quartzites and phyl- ! lite with carbonaceous bands I 1 Thanagazi Formation Andalusite-biotite-sericite schist, Delhi Supergroup I garnet-chlorite schist (Precambrian) (Aj'b'''.h0"" I Seriska Formation Brecciated and ferruginous-quart- I zites with stromatolites at the I ~ base ) l Kushalgarh Formation Impure siliceous marble with thin bands of chert and shale and stromatolites at upper part Alwar Group (Missing) Raialo Group (Missing) ----(Granite, basic and ultrabasic intrusives)------Aravalli Supergroup Not developed ranges in time from at least 1900 m.y. with mation is the oldest form:ttion of the Group, two cycles of folding and a younger and obviously the age will be more than metamorphism (Crawford, 1970). Gupta 533 m.y. of the youngest Bhakrol Formation. (1977) mentioned that the rocks have been On the basis of strom'ltolite Verma and subjected to repeated granitic activity at Barm:tn (1980) commented that the Kushal 1660 m.y., 1010 m.y., 950 m.y., 790 m.y. garh sedimentation started in the Lower and 735 m.y. Holmes (1949) carried out Riphean and continued up to Middle radiometric dating (733 m.y.) of Uraninite Riphean time (1800-1000 m.y.). from a pegmatite in the biotite gneiss at On geological evidences, Delhi Group Bisundri, Ajmer-Merwara and MonZlnite of rocks h:ts been placed below Vi ndhyans from a pegmatite at Soniana, Mewar. Ac and equated with Cuddapahs. However, cording to him the date, i.e. 735 ± 30 m.y. Crawford (1969) has correlated the Cud of Bisundri Uraninite is one of the very dapah sequence with the Lower Vindhyans. few acceptable ages as being of first class Cuddapah sedimentation took place from reliability. Aswathanarayana (1959) dated 1400 to 980 m.y. (Aswathanarayana, 580± 20 m.y. from the Samarskite from a 1962; Balasundaram & Ihlasubrahmanyan, pegmatite near Kishangarh, Rajasthan. 1973). On the other hand Vindhyans However, these younger dates support the covered a span of 1400 to 900 m.y. (Misra, observation of Heron (1953) that the pegm:t 1969). titic intrusions all along the Delhi Synclino While dealing with Precambrian strati rium did not take place at the sam~time. graphy in India on the basis of stromatolites, Vinogradov et al. (1966a) recorded 900± 50 Raha and Sastry (1982) also proposed that m.y. by K-Ar muscovite age from an the Delhi Supergroup may be correlated Erinpura pegmatite near Ajmer. The total with the Lower Vindhyan. However, the rock age of Erinpura type granite from new idea that Delhi is time equivalent, Ajmer is approximately 930 m.y. While at last in part, with Vindhyan needs more the Erinpura granite from Chhapoli was support from various disciplines. dated to 1000 m.y. (Crawford, 1975). Palaeoenvironment - Tlce study of stro A rock sample collected from the outer m:itolites in the horizon indicates that flank of Baraud anticline on northern side these stromatolites building algal community belonging to the Bhakrol Formation has grew in the form of a laminar sheet or mat been dated 533 ± 24 m.y. by Fission Track in Shallow muine conditions possibly in method of biotite. The Kushalgarh For- the intertidal zones. The silica rich solution MANDAL et 01.- MICROBIOTA FROM THE KUSHALGARH FORMATION 5 buried the community very quickly and Myxococcoides inornata Schopf, 1968 preserved the micro-organisms in situ. PI. 1, fig. 1 TAXONOMY Description - Cells in cluster or rarely The recorded assemblage consists of 10 solitary, 9-18.7 [lm in diameter (average genera and 17 species. The microbiota 12.7 [lm on 96 counts), spheroidal or described here are taxonomically distinct variously shaped due to mutual compression from each other particularly in their charac in a colony; surface psilate; walls thick teristic morphology. Presence of branching, about 0.5 !J.m; distinct sheath around the mode of septation, heterocyst, sheath and colony, individual cells not ensheathed. the reproductive structures (e.g. hormogonia) Remarks - The shap~and habit of these are considered to be distinctive in gene fossils are identical to Myxococcoides in ric delimitation. The shape, size and ornata Schopf (1968, pI. 83, fig. 7) from detail measu rements have been given the Bitter Spring Fonuation. However, secondary importance and used only for the present specimens are smaller ill size the specific identifications. The micro than the Bitter Spring. On the blsis of fossils recovered here show very little or the size the cells compare with M. retiCtllata no degradation at all. According to Schopf Schopf (1968), but in M. inornata the cells (1977) the coccoid fonus are referred to are smooth and not finely punctate or re Cyanophyceae on the basis of size and ticulate as in M. reticulata. morphologica.l featu res. The filamentous The taxon is common in the assemblage. forms are presumed to be cyanophycean Solitary cells are rarely found (PI. 1, fig. 5), in the presence of hormogonia, heterocyst which actually have originated from colonies in some of the fonus (e.g. honuogoni1 by fragmentation. These isolated cells in Palaeoscytonema misrae and heterocyst appear identical to Huronispora Barghoorn in Primorivularia robusta), brancb,i ng (false (in Barghoorn & Tyler, 1965). branching in Palaeoscytonema intermingla sp. nov. and true branching in Ghoshia bifurcata gen. et sp. nov) and very thick sheath in most of the forms. Myxococcoides compactus sp. nov. The empty sheaths of Chroococcacean Mandai & Maithy colony (e.g. Vesicophycus problematicus PI. 1, fig. 2; PI. 3, fig. 5 gen. et sp. nov.) and of filamentous forms (e.g. Animikiea septata) are most likely derived from the form recovered here. It is Diagnosis - Colony spheroidal up to 70 difficult to SlY with certainty that to which [Lm in diameter consisting of hundr[ds of form<; they actually belong. Empty sheath cell bounded by a thick, about 1.5 fJ.ln, of colonial form in all probability bdongs non-Iamellated granular sheath; cells 2.7-4.4 to Myxococcoides compactus as Vesico [Lm (average 3.7 [lm on 38 counts) in phycus rarely contai ns few cells inside (PI. 2, diameter, arranged irregularly; surf<;ce fig. 17) identical to the cells of M. compactus psi late to finely granulose; wall about 0.2 in shape and size. On the contrary, the [Lm thick; individual cells not ensheathed. empty sheath of filaments (e.g. Animikiea Reproduction possibly by vegetative division septata) are derived from more than one in more than one plane. taxon as they have different types of apices. HolotYP2 - PI. 1, fig. 2; slide no. 6818; stage coordinate 12.5 X 100. Type Locality - 1 km east Baraud SYSTEMATIC DESCRIPTION of Village. ALGAE Etymology - With reference to compact arrangement of cells. FAMILY - CHROOCOCCACEAE Comparison & Discussion - Myxococ coides compactus sp. nov. is observed fre Genus - Myxococcoides Schopf, 1968 quently in the assemblage. The species differs from the known species of Myxococ Type Species - Myxococcoides minor coides in its smliler cell size and colony Schopf, 1968. consisting of about hundreds of cells. 6 THE PALAEOBOTANIST Myxococcoides minor Schopf, 1968 Gloeoeapsamorpha prisca Zalessky, 1916 PI. 1, figs 3,4; PI. 3, fig. 24 PI. 1, fig. 7 Description -Globular colony up to 58 (Lm Description - Colony large forming stiff in diameter, composed of few to 20 cells mat with a number of concentric sheaths; embedded within a non-lamellated sheath cells form secondary colonies, 10-15 in of about 1.2 fLthick; cell outline spheroidal number arranged irregularly, 9-] 5.2 fLm or polygonal due to compression, 4.4-8.5 in diameter, spherical or oval in shape due 110m in diameter (average 6.6 fLm on 16 to compaction; sheath around the colony counts); adjacent walls of cells appear to and individual cells present, about 1.5 fLm be common; wall about 0.5 fLm thick; sur thick. face psilate. Remarks - Gloeocapsamorpha prisca is Remarks - Present specimens are sm3.lIer uncommon in the assemblage. ti1an the specimen of Schopf (1968) from Bitter Spring. The taxon is common in the assemblage. Gloeocapsamorpha karauliensis Maithy & Mandai, ]982 PI. 1, fig. 6 Genus - Palaeoanacystis Schopf, 1968 Description - Cells spherical to oval due Type Species - Palaeoanacystis vulgaris to mutual compaction, thin-walled and Schopf, 1968. smooth, 4.4 to 9 fLm in diameter (5.5 fJ.m on average on 27 counts). Cells form secondary colonies within the parent colony; Palaeoanacystis vulgaris Schopf, 1968 11 secondary colonies observed to form a big colony; individual cells and colony PI. 4, figs 26-28 ensheathed, colony about 10 to 33.2 fLm in diameter. Description - Large colony mlde up of Remarks - The taxon is rare in the as a number of coccoid cells, palmelloid or semblage. Cells are smaller in size than cylindricl1, generally dome-shaped and G. karauliensis described from Vindhyans apparently without any mucilage covering. of Rajasthan by Maithy and Mandai (1983). [ndividual cells spheroidal to elliptical due to mutual compaction, not enSheathed, 4.5-11 fJ.m in size (average 6.5 fLm on 55 measurements), cells appear to have FAMILY - OSCILLATORIACEAE m'l.rginal wllls in common with the neigh b~uringcells which are pronounced near Genus - Palaeolyngbya Schopf, 1968 emend. the mugin; surface smooth. Discussion - Palaeoanacystis is the mono Type Species - Palaeolyngbya bargho specific genus erected by Schopf (1968) orniana Schopf, 1968. from the Bitter Spring Formation. Baraud Remarks - The generic diagnosis of specimens are commonly palmelloid and Palaeolyngbya Schopf (1968) is based on marginal walls of the neighbouring cells the monotypic species - P. barghoorniana. appear to be common. The present speci Therefore, it has limited the scope to mens compare exactly with the photograph accommodate other forms. As our form of P. vulgaris given by Schopf (1968, pI. 82, is overlapping in all significant morpho fig. 7) from the Bitter Spring Form3.tion logical characters with extant Lyngbya, of Australia. The taxon is not common the generic diagnosis of Palaeolyngbya is in the assemblage. enlarged here to accommodate other forms having comparable morphology with extant Lyngbya. Genus - Gloeocapsamorpha Zalessky, 1916 Emended Diagnosis - Filament broad, multicellular, uniseriate, unbranched, slightly Type Species - Gloeocapsamorpha prisca to strongly constricted at septa; cross wall Zalessky, 1916. distinct, either partial or complete, sheath MANDAL el al.- MICROBIOTA FRoM THE KUSHALGARH FORMATION 7 dis\inct, hyJline, non-lam~lIatedand firm. Holotype - PI. 3, fig. 20; slide no. 6816; Trichomes solitary, straight to variously stage coordinates 36.8 x97. curved. Apical cell may be distinct. Re Locality - 1 km east of Baraud Village. production by hormogonia. Etymology - With reference to long fila ment. Comparison & Discussion - Only one Palaeolyngby,'l distinctica sp. nov. Mandai complete specimen observed which is 500 & Maithy [Lm long. The terminal portion of the PI. 2, figs 10, 11 filament is broad possibly due to compres sion. Reproductive structure was not ob Diagnosis - Filament in bunch, variously served. P. elongata sp. nov. is ch'uacterised curved up to 200 fJ-m long (incomplete by granular spindle-shaped basal cell larger specimen); trichome solitary, multicellular, than the rectangular medial cells which uniseriate and unbranched; septa distinct, mlke the species distinct and differs frOID widely spaced towards apices, faintly to other known species of Palaeolyngbya. moderately constricted at septa poi nt; basal cell swollen, 10 to 13 fJ-m long and 5 to 7 , [Lm broad (on 4 counts); medial cells nearly Palaeolyngbya baraudensis sp. nov. Mandai quadrangular (as long as broad), 5 to 8 & Maithy [Lm; side walls often depressed, smooth to PI. 1, fig. 9 finely granular surface; sheath firm, thin, non-Iamellated; reproduction possibly by Diagnosis - Filaments in bunch, up to hormogonia. 200 [Lm long, trichome single with broad Holotype - PI. 2, fig. 10; slide no. 6818; basal cell; medial cells discoid, broader stage coordinates 53 X 103.5. than long, 2/3 to 3/4, not constricted at Type Locality - 1 km east of Baraud septa, 13-18 [Lm broad and 2-4 [Lm long, Village. terminal cells 4-6 IJ.m broad and 2-3 [LID Etymology - With reference to distinct long, cell surface granular; septa straight quadrangular medial cells. or concave; sheath thick, ad pressed to Comparison & Discussion - Palaeo- trichome, faintly laminated; reproduction lyngbya barghoorniana Schopf (1968) differs not known. from P. distinctica sp. nov. in hlVing Holotype-PI. 1, fig. 9; slide no. 6816; partially septate disc-shaped medial cells stage coordinates 1 x94.6. whereas in present species the medial cells Locality - 1 km east of B1faud Village. are quadrangular, completely septate and Etymology - With reference to the Baraud sheath is distinct. P. elongata sp. nov. com Village from where the sample was collected. pares with P. distincta in having broad bas:1! Comparison - Palaeolyngbya baraudensis cell but medial c~llsare discoid. On the sp. nov. compares with P. elongata sp. nov. basis of exomorphic features P. distinctica in morphology, but the former differs in sp. nov. compares with the extant Lyngbya having curved basal cell. Moreover, basal baculum Gomont. The taxon is rare in cell is not spindle-shaped. occurrence. Genus - Oscil/atoriopsis Schopf, 1968 Palaeolyngbya elongata sp. nov. Mandai & Maithy Type Species - Oscillatoriopsis obtusa PI. 3, fig. 20 Schopf, 1968. Diagnosis - Filament up to 500 [Lm long, isolated, variously curved; trichome single, Oscillatoriopsis obtusa Schopf, 1968 unbranched and septate; medial cells disc PI. 3, fig. 23A shaped, 5.3 [LID long, 7 [Lm broad; basal cell larger than the medial cell, spindle Description - Trichome multicellular, shaped, granulose; sheath firm, thin and variOUSly curved, uniseriate, unbranched, adpressed to trichome; reproduction possibly solitary, up to 175 fJ.m long, not constricted by hormogonia. at septa, septation complete; med ial cells 8 THE pALAEOBOTANIST cylindrical, nearly isodiametric, 8 to 11.1 pose here to consider Siphonophycus Schopf fLm long and 8.5 to 10.1 fLm broad; apical (1968) as junior synonym of Animikiea cell gum-drop shaped, cylindrical, 10 fLm Barghoorn (1965). long and 8.5 fLm broad; sheath not obs Emended Diagnosis - Unbranched, as cured; reproduction not known. eptate, tubular empty sheath of filamentous Remarks - Only one specimen observed algae. in the assemblage. Genotype - Animikiea septata B3.rghoorn, 1965. Due to this change in the generic status Genus - Animikiea Barghoorn, 1965 emend. of Siphonophycus the following transfers Mandal & Maithy b<:come necessary and is being done here accordingly. Synonym: Animikiea septata Barghoorn emend. 1968 SiphonophycllS Schopf, p. 67 I. Mandai & Maithy PI. 2, fig. 16; PI. 3, figs 18, 19 Remarks - Barghoorn (1965 in Bar ghoorn & Tyler, 1965) proposed Animikiea for the multicellular unbranched filaments Synonymy: (without trichome) straight or curved with closely spaced septa. Individual cell 1965 Animikiea septata Barghoorn Jn much wider than I,:>ng. Enclosing sheath Barghoorn & Tyler, p. 576, fig. 3. offilament distinct, thick-walled and granular. 1968 Siphonophycus kestron Schopf, p. 671, This genus was later restudied by Awramik pI. 80, figs 1-3. and Barghoorn (1977) and according to 1971 Siphonophycus kestron Schopf in them the septate appearance may be due Schopf & Blacic, p. 948, pI. 109, figs to the wrinkling of external sheath and 3, 4. actually is only surficial feature. Schopf 1977 Sheaths, Oehler, 1977, figs A, G, H. (1968) while instituting the genus Siphono 1977 Animikiea septata Barghoorn in phycus from the Bitter Spring Formation Awramik & Barghoorn, p. 139, fig. 7A. of Australia opined that it resembles closely Emended Diagnosis - Sheath (without to Animikiea Barghoorn. The only differ trichome) cylindrical, tubular, aseptate, un ence was the presence of closely spaced branched, variously curved; surface smooth septa, which Schopf (1968) considered to to granulose; apices broad, capitate to bluntly pointed. b~closely-spaced, punctate surficial ridges, Type species - Fig. 3, Part 2, Barghoorn, and not p<:n~tratingin the tubular lumen. According to Schopf (1968, p. 671)" the 1965 in Blfghoorn and Tyler, 1965. Remarks - The tubular cylindrical sheath s~pta"of Animikiea septata, therefore, t seem quite analogus to the finely punctate from the Delhi Supergroup is much broader surface ornamentation of Siphonophycus than the type specimen. The surface of kestron (pI. 80, fig. 2). Altbough morpho the studied specimens show various surficial pattern from smooth to granulose. The logy of these tW0 microfossil genera s~ems quite similar but the apical portion of A. granulose surface gives a pseudosepta appear septata is unknown. The apical part can ance. Several specimens show the presence not be taken as character for generic sepa of apices which are variable in shape. This ration, as the presence of apex is only taxon is very common in the assemblage. a chance of preservation. In our study we have found specim~nswith and without apices. Surface features of these speci Animikiea punctata (Maithy) comb. nov. mens range from psi late to granular Mandai & Maithy and aseptate to septa-like structure which could be due to preservation. We, there Synonymy: fore, feel that the characters of Animikiea and Siphonophycus are overlapping and 1975 Siphonophycus punctatus Maithy, not distinct enough for the institution p. 137, pI. 1, fig. 5. of two distinct genera. Hence, we pro- Diagnosis - As in Maithy, 1975. MANDAL et 01.- MICROBIOTA FROM THE KUSHALGARH FORMATION 9 Animikiea indica (Nautiyal) comb. nov. 1.2 fLm thick, multicellular and false Mandai & Maithy branched laterally; trichome and branches enclosed in the same sheath; septa distinct, Synonymy: thin but indistinct towards terminal portion, inflated and curved at base, cells discoid, 1978 Siphonophycus sp. A, Nautiyal, p. broader than long, nearly 3/4; width of 261, fig. 9 trichome 11-13.2 fLm at base, 5.5-8.5 fLm 1980 Siphonophycus indicus Nautiyal, p. 3, at middle and 2 fLm at tip, surface granu fig. IA lose; sheath adpressed to trichome and Diagnosis - As in Nautiyal, 1980. diffluent at the apices. Reproduction not known. Holotype - PI. 2, fig. 12; slide no. 6816; Animikiea beltensis (Horodyski) comb. nov. stage coordinates 62.7 x95. Mandai & Maithy Locality - 1 km east of Baraud Village. Etymology - With reference to occur Synonymy: rence in India. Comparison & Discussion - The present 1980 Siphonophycus beltensis Horodyski, p. taxon is characterised by false branching 654, pI. 1, fig. 4. and the sheath encloses trichome and Diagnosis - As in Horodyski, 1980. branches. However, reproductive struc tures have not been observed. Palaeo Animikiea crassiuscula (Horodyski) comb. scytonema indica sp. nov. differs from P. nov. Mandai & Maithy moorhousii Edhorn (1973) in being the tri chome and branches within the sheath, Synonymy: robust in form and having curved inflated base. Moreover, reproductive structures are 1980 Siphonophycus crassiusculum Horo not known. P. intermingla sp. nov. com dyski, p. 656, pI. 1, figs 6, 7 pares with P. indica in laterally false branched characters but differs in the absence Diagnosis - As in Horodyski, 1980 of curved inflated base. P. misrae sp. nov. differs as it reproduces by 6-7 cells long hor FAMILY - SCYTONEMATACEAE mognia and has a thin filament. The taxon is common in the Baraud assemblage. Genus - Palaeoscytonema Edhorn, 1973 Type Species - Palaeoscytonema moor housii Edhorn, 1973. Palaeoscytonema intermingla sp. nov. Remarks - Ed horn (1973) and Maithy Mandai & Maithy and Shukla (1977) recorded microfossils PI. 3, figs 22, 23 showing affinities with the living Scytonema and separately erected the genus Palaeoscy Diagnosis - Filaments interwoven, 10.5 tonema with different types. Later, Maithy to 13 fLm broad (on 6 counts), false (1980) transferred Palaeoscytonema of branched; false branches lateral; sheath Maithy and Shukla (1977) to a new genus thick, ad pressed to trichome; trichome Neoscytonema to validate the same. The about 5.5 to 7 !Jomqroad; cells rectangular, present taxon possesses false branch, hor septa faint, not attenuated at septa point; mogonia and thick sheath which overlap branches swollen at the tips with rounded with the generic circumscription of Palaeo apices. scytonema Edhorn (1973). Holotype - PI. 3, fig. 22; slide no. 6816; stage coordinates 4 x92.9. Locality - 1 km east of Baraud Village. Palaeoscytonema indica sp. nov. Etymology - With reference to interming Mandai & Maithy ling nature of branches. Pl. 2, fig. 12 Comparison - Palaeoscytonema inter- mingla sp. nov. differs from P. moorhousii Diagnosis - Filament single up to 250 Edhorn (1973), P. indica sp. nov. and P. fJ-mlong; trichome solitary, sheathed; sheatb misrae sp. nov. in possessing intermingling 10 THE PALAEOBOTANIST filaments and false branches with swollen branched, ensheathed fully; constricted at and rounded apices. The taxon is rare septa basally; sheath non-lamellated about in the assembl3.ge. 1 flm thick; basal cells spherical, broader than long, 12.2 flm long and 18 flm broad; Palaeoscylonema misrae sp. nov. medial cells rectangular, closely placed, Mandai & Maithy septa faint; heterocyst basal, si ngle hemis pherical, 18 flm long and 15.5 flm broad; PI. 2, fig. 13 akinite not known. Holotype - PI. 3, fig. 23B, slide no. 6817; Diagnosis - Filam ~ntsiso13.ted, variously curved, up tD 50 flm long; trichome solitary, stage coordinates 61.6 x94.2. unbranched, faintly con,tricted at septa; Locality - As noted above. cells drum-shaped, 6 to 10 flm long, 4 to 7 Etymology - With reference to robust flm broad, side walls straight to convex, m::>rphology. basal cells larger th'ln medial ones, 10 to Comp:J.rison & Discussion - The taxon 12.2 flm long and 6.5 to 8 flm broad; is represented by only three specimens. The sheath firm, thick ab;)Ut 1.2 fJ.m; reproduc terminal portion in all the specimens are tion by hormogonia, 2 to 3 hormogonia broken, therfore, the presence of terminal formed at a time, up to 7 cells long. hair could not be ascertained. However, Holotype-PI. 2, fig. 13; slide no. 6816; the basal heterocyst, broader basal cells stage coordinates 47.1 x97.3. and gradual attenuated trichome overlap Locality - 1 km east of Baraud Village. with the circumscription of Primorivularia Etymology - In honour of Prof. R. C. Edhorn (1973) except the character of ter Misra, former Head of the Geology Depart minl1 hair. Primorivularia robusta sp. nov. ment, Lucknow University for his contri differs from P. thunderbayensis Edhorn bution to the Prec3.mbrian research work (1973) in being robust and the trichome in India. fully covered by sheath. Comparison & Discussion - Palaeo- scytonema misrae sp. nov. is very distinct ORDER - STlGONEMATALES in morphology and differs from other species of Palaeoscytonema in possessing FAMILY - CAPSOSIRACEAE 6-7 cells long hormogonia formed 2-3 at a time. However, filament in the assem Genus - Ghoshia gen. nov. Mandai & Maithy blage is being observed (PI. 2, fig. 14) with broad apical cell nearly identical in measure Type Species - Ghoshia bifurcata gen. ment with P. misrae. In this filament the et so. nov. hormogonia consist of only two cells. Iso Diagnosis - Thallus heterotricbous, erect lated hormogonia, as figured in PI. 2, fig. filaments arising from a basal horizontally 15, present in the assemblage are bei ng creeping thallus, densely packed, truely ~ supposed to belong to P. misrae on the laterally branched, with cells in one or two basis of size measurements. The form is series; sheath absent; reproduction not very rare in the assemblage. observed. Etymology - In honour of Prof. A. K. FAMILY - RIVULARIACEAE Ghosh, emeritus scientist, Department of Botany, Calcutta University, Calcutta. Genus - PyimoYivularia Edhorn, 1973 Ghoshia bifurcata sp. nov. Type Species - Primorivularia thunderba Mandai & Maithy yensis Edhorn, 1973. PI. 4, figs 29-31 Primorivularia robusta sp. nov. Diagnosis - As for the genus with the Mandai & Maithy following characters; cells drum-shaped to PI. 3, fig. 23B rectangular, dark coloure'd, constricted at septa, 5 to 9.3 flm in diameter (average 5.5 Diagnosis - Filaments solitary, up to 150 fLm on 33 counts), wall about 0.5 flm thick flrn; trichome uniseriate, multicellular, Ul~-and surface psilate; branching irre~ular, MANDAL el 01.- MICROBIOTA FROM THE KUSHALGARH FORMATION 1\ Locality - 1 km east of Ruaud Village. Locality - I km east of B3faud Village. Holotype - PI. 4, fig. 30; slide no. 6817; Comparison & Discussioll - Horodyski stage coordi n'ltes 52.5 x 95.2. and Donaldson (1980) described some large Etymology - With reference to forking envelopes as Archaeoellipsoides from Arctic nature of erect filaments. Canada which differs from Vesicophycus in Discussion - Stigonematales is the most bei ng elli psoidal, pear or sausage-shaped. evolved order among the blue-green algae. In all probability, these are the empty This group of algae is characterised by colony sheaths of coccoid forms which are heterotrichous filaments with true branching abundant in the assemblage. Two vesicles and multiplic3tion by hormogonia and hor were observed where 3-5 coccoid cells are mocysts. The present taxon exhibits hetero still present inside. These coccoid cells trichous habit and lateral branching which are similar to the cells of Myxococcoides appears to be true. Reproductive struc compactus sp. nov. (PI. 2, fig. 17). In other tures, however, are not known. On the cases the rupture of the wall indicates basis of known v~getativecharacters, putting possibly the path for the outlet of the coc more stress upon the true branching of coids. Other possibility is that some of heterotrichous filaments, this form compares these vesicles used to contain zygospores well with the living algae Stauromatonema arid after their liberation from the vesicles Fremy (Desikachary, 1959, p. 5(7) be the empty vesicles become collapsed with longing to Stigonematales. Thus this is crumpled surface. As no comparable struc the earliest fossil record of Stigonem'ltalean ture with the present form is known a new algae. This group of algae is known pre name Vesicophycus is erected to accom viously from the Middle Devonian of Rhynie modate the spherical empty sheaths. Chert (Croft & George, 1959). The present record will m3.terialistically contribute to the understanding of the early evolution DISCUSSION of form. The genus Choshia is common in the assemblage. Structurally well-preserved microbiota comprising blue-green algae is recorded for the first time from the Ajabgarh Group. INCERTAE SEDIS This is the most diversified Precambrian biota from India. The assemblage com Genus-Veslcophycus gen. nov. MandaI & Maithy prises 10 genera and 17 species. These Type Species - Vesicophycus proble- taxa represent four natural families be maticus n. sp. longing to three orders - Chroococcales, Nostocales and Stigonematales. The PI. 3, fig. 25; PI. 4, fig. 32 presence of Stigonematales in the assemblage "'~..:;I..' has been suggested by vegetative characters . Diagnosis - Solitary empty envelope, The diversification of the assemblage is ID'linly spherical or oval due to various evidenced by the varying morphology they foldings on the surface; folds common exhibit. Sheath is present conspicuously and irregular, surface without any ornamen in all the forms except Choshia, which may tation but rough. No pore or mark on ad pressed to the trichome (e.g. Palaeoscy surface. tonema indica) or loose (e.g. Palaeolyngbya Etymology - With reference to nature distinctica). In Primorivularia robusta of vesicle and possible algal affinity. sheath is not discernible in the apical portion of the trichome. The reproductive struc ture observed in the filamentous forms is Vesicophycus problematicus sp. nov. honnogonia (e.g. Palaeoscytonema misrae). Mandai & Maithy Isolated hormogonia are also found in the assemblage (PI. 2, fig. 15) which may belong Diagnosis - As for the genus. to P. misrae like forms. Heterocyst is Etymology - With reference to doubtful rare (PI. 3, fig. 23), but akinite or other nature of vesicles. types of spores are totally absent. Vegeta Holotype - PI. 4, fig. 32; slide no. 6816; tive cells also show various shapes stage coordinates 43.2 x 101.4. quadrangular (e.g. Palaeolyngbya distinctica), 12 THE PALAEOBOTANIST rectangular (e.g. Pafaeoscytonema baraud diverse biota is known till today, which ensis) and discoidal (e.g. P. indica). is represented by Chroococcaceae, Oscilla I Basal cells in Palaeolyngbya indica is toriaceae and Scytonemataceae. The ~~ bigger than the mecial c~1lwhereas they present assemblage also contai ns these ," are smaller or of the same size as in Palaeo families with more developed structures scytonema indica. The assemblage is do such as hormogonia, heterocysts and with minated by the filamentous forms which frequentIy branched filaments, which make constitute 65 per cent of the total assemblage. the assemblage unique. On the whole However, coccoid forms are common in the Baraud assemblage demonstrates ad occurrence. It is interesting to note that vancement in evolutionary level tha n the there is n;) tax'! of a single cell. The colonial Vindhyan biota though on geological evi habit suggests higher level of evolutionary dences it is believed that Vindhyans are stage. The colonies are in the form of younger than Delhi Supergroup. algal mat which ultilmtely form the bios The assemblage compares well with Bitter trome of the strom1tolite. Spring flora of Australia (Schopf, 1968; Branching perhaps h'\s em~rgedas most Schopf & Blacic, 1971). In both the as significant event in the assemblage. Re semblages Chroococcaceae, Oscillatoriaceae cord of false (bteral) branching is m::agre and Rivulariac::ae appear to be common. in the early rocks. E":lflier Edhorn (1973) The Bitter Spring microflora is very rich reported false branching in pfaeoscy and much more diversified which contain tonema moorhousii from Canada. Baraud probable Chloroptlycean and Rhodophycean microbiota frequently exhibits false branch algae, fungi and bacteria, which are absent ing (e.g. Palaeoscytonema intermingla and in B3.faud. Similarly in Scytonemataceae, P. indica). The branching in Ghoshia bifur true and false branching and reproductive cata has been suggested to be true one and structures are totally absent from the Bitter therefore it has been pl3.ced in Stigone Spring Formation. Thus on one hand matales, where true branching commonly the appearance of eucaryotic organism is occur. If the suggested affinity of Ghoshia significant in Bitter Spring while the appear with the more advlnced order of blue-green ance of true branching habit is most algae stands right on the basis of true significant feature in Baraud. This coin branching then highest level of development cidence indicates that true branching and of vegetative characters occurred in Delhi nucleated cells probably appeared within Supergroup. No other record of true short time interval. Assemblages reported branching is known so far from the by Edhorn (1973)-Animekie, Thunder Proterozoic. The earliest record of the Bay, Ontario; Hofmann and Jackson (1969) preserved Stigonematalean fonn is available -Belchar island, Hudson Bay; Hofmann from the Middle Devonian Rhynie chert by (1976) - Belcher island; Oehler (1977) Croft and George (1959). H.Y.C. Pyritic Shale Member, Australia;Muir Comparison with other assemblages (1976)-Amelia Dolomite, Australia; and Structurally preserved microbiota are now Maithy (1975)-Bushimay Supergroup, Zaire known from the various Proterozoic rocks differ in the constituents of micro biota. of India. However, the assemblages re Moreover, both false and true branching ported earlier by Maithy and Shukla (1977), present in this assemblage is characteristic. Maithy and Gupta (1983), Maithy and . From the above comparison it is evident MandaI (1983) from Vindhyans and Nautiyal that all the assemblages resemble in (1978) from the Kumaun Him3.laya are common occurrence of Chroococcaceae and comparable as they comprise coccoid and Oscillatoriaceae. However, all of them filamentous forms comparable with blue differ in point to point comparison due to green algae. Chroococcaceae and Oscilla different climatic factors and evolutionary toriaceae are also common in all the scales. It is possible that the evolution assemblages. However, the Baraud assem proceeded in more or less same direction blage is entirely different from all the above but with different forces in different basins. described assemblages in the dominance According to Schopf and Blacic (1971) the of filamentous forms and total absence of correlation is possible only over short dis cryptarchs. In the Su ket Shale microflora tances and when factors influencing species (Maithy & Shukla, 1977) wdl-preserved dispersed are thoroughly considered. MANDAL et al.- MICROBIOTA FROM THE KUSHALGARH FORMATION 13 The occurrence of such diverse micro strata will certainly strengthen the basis biota is a significant addition to the for closer correlation. It appears that Indian Precambrian record. Microbiota serious attempt is now needed before known so far from the Vindhyans is not putting any final comment on the correla diverse like from Baraud. However, more tion between Delhi Supergroup and Vin slmpling covering wide ecologically varying dhyans. REFERENCES ASWATHANARAYANA,U. (1959). Age of the Samars Lakes Group, Arctic Canada. Precambrian Res., kite of Kishangarh, Rajasthan, India. Bull. 11: 125-159. geol. Soc. Amer., 70: 111. KRISHNAN, M. S. (1982). Geology of India and ASWATHANARAYANA,U. (1962). Age of the Cudda Burma. CBS Publishers & Distributors, India Nh, India. 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Proterozoic microfossils from DESIKACHARY,T. Y. (1959). Cyanophyta. I.C.A.R. the Amelia Dolomite, McArthar Basin, Northern Monograph on algae, New Delhi. Territory. AIcheringa, 1: 143-158. DUTI, G. N. & SHRIVASTAVA,R. N. (1975). Fossil NAUTIYAL, A. C. (1978). Discovery of the cyano flora in the Alwar quartzite, Firozpur Jhirka, phycean algal remains and microplanklons in Gu:gaon District, Haryana. G.S.1. Misc. Pub!., the Late Precambrian schistose phyllites and its 23 (I): 149-156. bearing on the age of the Amri Unit, Garhwal EDHORN, ANNA-STINA (1973). Further investi· Himalaya, India. Curl'. Sci., 47 (9): 295 gations of fossils from the Animekie, Thunder 299. Bay, Ontario. Proc. geol. Assoc. Canada, 25: NAUTIYAL, A. C. (1980). Cyanophycean algal re 37-66. mains and palaeoecology of the Precam GUPTA, Y. J. (1977). Indian Precambrian Strati brian Gangolihat dolomites Formation of the graphy. Hindusthan Publishing Corporation Kumaun Himalaya. Indian J. 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Palynol., 8: 123 STUPNIKOVA, N. I., B1B1KOVA,E. V., KNORRE, 131. K. G. & MALNIKOVA, G. L. (1966). Geochrono SALUJHA, S. K.,REHMAN, K. & RAwAT, M. S. (1971 b). logy of the Precambrian of. India. Moscow Fossil palynomorphs from the Vindhyan of Academy 0/ Science: 394-408. Rajasthan (India). Rev. Palaeobot. Palynol., VISWANATHIAH, M. N., VENKATACHALAPATHY,V. & 11 (1): 65-83. MAHALAKSHAMAMMA,A. P. (1975). Microorga SCHOPF, J. W. (1968). Microflora of Bitter Springs nisms from the Kaladgi Basin, South I ndia and Formation, Late Precambrian, Central Australia. their stratigraphic significance. J. geol. Soc. J. Palaeontol., 42: 651-688. India, 16: 199-208. SCHOPF, J. W. (1977). Biostratigraphic usefulness VISWANATHIAH, M. N., VENKATACHALAPATHY,V. & of stromatolitic Precambrian microbiotas: A AMTUL, KHADEER (1976a). Microfossils from preliminary analysis. Precamb. Res., 5: 143-173. the Badami Group, Karnataka, South India. SCHOPF, J. W. & BLACIC, J. M. (1971). New micro J. geol. Soc. India, 17 (3): 340-345. organisms from the Biller Springs Formation VISWANATHIAH, M. N., VENKATACHALAPATHY,V. & (Late Precambrian) of the North-Central Amadens DODDAtAH, D. (1976b). Palynofossils from the Basin, Australia. J. PalaeOiltol., 45 (6): 925-960. Bhimas, Karnataka, South India. hoc. VI Indian SCHOPF, J. W. & PRASAD, K. N. (1978). Microfossil Coli. Micropalaeont. Strat., Varanasi. 384 in Col/enia-like stromatolites from the Proterozoic 389. Vemapalle Formation of the Cuddapah Basin, VISWANATHIAH, M. N., VENKATACHALAPATHY,V. & India. Precambrian Res., 6 (3): 347-366. MAHALAKSHMAMMA,A. P. (1979-80). Acritarchs StNGH, R. Y., TIWARt, B. S. & GUPTA, V. J. (1978). and other associated microfossils of the Lokapur Palynology of the rock salt deposits of Mandi Formation, Kaladgi Group (Precambrian-Camb and its applications on the age ofShali Formation. rian), South India. hoc. IV inl. Palynol. Contribution to the Himalayan Geology, 1: 97-105. Con/., Lucknow (1976-77),2: 71-77. VENKATACHALA, B. S. & RAwAT, M. S. (1973). ZALESSKY, M. D. (1916). In A. Eisenack, 1960. Organic remains from the Bhima Basin and re- Senck. leth., 40 (1/6): 13-26. EXPLANATION OF PLATES (All figures are X 1000 unless otherwise stated; stage coordinates given for Leitz Dialux-20) PLATE 1 PLATE 2 1. Myxococcoides inornata Schopf showing a small 10, 11. Palaeolyngbya distinctica sp. nov. showing cluster within organic matrix; phase interference thick sheath, quadrangular cells; phase inter photograph, slide no. 6816, stage coordinates ference photograph; slide no. 6818; fig. 10, holo 58.4 x 98.2. type, stage coordinates 53 x 103.5; fig. 11, 2. M. compactlls sp. nov., holotype; phase inter 31.3 x 100.2. ference photograph; slide no. 6818, stage co 12. Palaeoscytonema indica sp. nov., holotype, slide ordinates 12.5 x 100. no. 6816, stage coordinates 62.7 x 95;x 500. 3, 4. M. minor Schopf showing different number 13. Palaeoscytonema misrae sp. nov., hoJolype, slide of cells in the colony, slide no. 6818; fig. 3. no. 6816, stage coordinates 47.1 x 97.3. Stage coordinates 36 x 106; fig. 4. 43x 107.4. 14. A filament showing two-celled hormogonia, 5. A solitary cell, comparable with Huronispora slide no. 6816, stage coordinates 53.2 X Barghoorn, seems to be detached from M. 106.3. inornata colony, slide no. 6818, stage coordinates 15. An isolated hormogonia comparable with the 44.5 x 99. hormogonia of P. misrae; slide no. 6818, stage 6. GloeocapsamOlpha karauliensis Maithy & coordinates 53.3 x 103.3. Mandai, slide no. 6817, stage coordinates 30.7 x 16. Animikiea septata Barghoorn, apical portion, 106. slide no. 6816, stage coordinates 33.2 x 7. G. prisca Zalessky, slide no. 6818, stage coordi 97.5. nates 35 x 105.5. 17. An empty sheath of colony identical to Vesico 8. Animikiea septata Barghoorn showing apical phycus gen. nov. still containing 3 cells inside part, slide no. 6816, stage coordinates 49.5 x 97. which are similar to Myxococcoides compactus, 9. Palaeolyngbya baraudensis sp. nov., slide no. slide no. 6816, stage coordinates 49.8 X 6816, stage coordinates 51.1 x 94:6. 500. MANDAL e/ al.- MICROBIOT A FROM THE KUSHALGARH FORMATION 15 PLATE 3 25. M. compac/us sp. nov., slide no. 6818, stage coordinates 36.5, x 107.5, x 500. 18, 19. Animikiea sepIa/a Barghoorn, fig. 18, without apex showing false septation, slide no. 6816, stage coordinates 38.7 x 9604; fig. 19 showing PLATE 4 apex, false septation, slide no. 6816, stage co ordinates 43.5 x 92.1. 26-28. Palaeoanacyslis vulgaris Schopf, fig. 26, 20. Palaeolyngbya elonga/a sp. nov., holotype, note slide no. 6817, stage coordinates, 60 x 99, granular nature of trichome prominent in the x 500; fig. 27, a portion enlarged of fig. 26, apical part, slide no. 6816, stage coordinates x 1000; fig. 28, slide no. 6816, stage coordi 36.8 x 97; >~750. nates 30.5 x 95.9, x 500. 21, 22. Palaeosey/onema in/ermingla sp. nov., show 29-31. Choshia bi/urea/a gen. et sp. nov., fig. 29 ing false lateral branching; fig. 21, hoJotype, showing initiation of heterotrichous condition, slide no. 6817, stage coordinates 48.2 x 96.8; slide no. 6818, stage coordinates 39.3 x 106.8; fig. 22, slide no. 6816, stage coordinates, 4404 x fig. 30, holotype showing true branching in 92.9. aerial filament, slide no. 6817, stage coordinates 23. A, Osci//a/oriopsis obtusa Schopf and B, Primori 52.5 x 95.2; fig. 31, slide no. 6817, stage co vularia robusla sp. nov., holotype, slide no. ordinates 36 x 9604. 6817, stage coordinates 61.6 x 94.2. 32. Vesicophycus problemalicus gen. et sp. nov., 24. Myxoeoceoides minor Schopf, slide no. 6818, holotype, slide no. 6816, stage coordinates, stage coordinates 5904 x 107.2. 43.2 x lOlA. , ( MANDAL el 01.- MlcROBIOTA FROM THE KtJSHALGARH FORMATION 17 PLATE 2 18 THE PALAEOBOTANIST Pf:ATE3 MANDAL t!f al.- MICROBIOTA FROM THE KUSHALGARH FORMATION 19 \ tt~1O.· ,1_ .. .. PLATE 4