首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
SHARMA  B. D. 《Annals of botany》1970,34(5):1071-1077
Seeds of Williamsonia collected from Amarjola in the RajmahalHills, Bihar, are described. Mature seeds are found in ripe,naked, bractless fructifications. Seeds are oblong or ovate,stalked, dicotyledonous, partially endospermic, and have longmicropyles. The seed coat is differentiated into an outer coveringof tubular cells, middle parenchymatous true integument, andan inner vascularized layer which forms after fertilizationand as a result of modification of the peripheral portion ofnucellus.  相似文献   

2.
3.
4.
Three types of petrified filician rhizomes and their associatedpetioles and roots from the Rajmahal Hills, Bihar, India aredescribed. Two rhizomes possess protostelic vasculature withmesarch protoxylem elements and exarch protoxylem points. Theformer are gleicheniaceous while the latter is described asa schizaeaceous rhizome. The associated petioles possess typicalgleicheniaceous anatomy while the roots show variations in thestructure of epiblema and cortex. filician fossils, Jurassic, Actinostelopteris pakurense, Gleichenia sonajoriense, Solenostelopteris jurassica, Gleichenioamyelon diarcha, Filicoamyelon cryptogrammoides Filicoamyelon actinostachyoides  相似文献   

5.
6.
7.
A prolific foraminiferal assemblage comprising 51 species is reported from Jurassic sediments of the Chari Formation, Jumara Hills, Kutch, India. The assemblage is dominated by the families Vaginulinidae and Nodosariidae. Sixteen species are reported for the first time from the Indian region including one new species. The foraminiferal assemblage suggests a Callovian to Oxfordian age for the studied sequence. The depositional environment of the studied sequence is interpreted based on foraminiferal evidence combined with lithology and megafauna which indicates that the sediments of the Chari formation exposed at Jumara Hills were deposited in a shallow-water, near shore, environment with fluctuating shoreline in a tectonically unstable shelf zone. The Jumara Hills foraminiferal assemblage exhibits close affinity with certain other Jurassic assemblages of the Tethyan Realm and helped in drawing palaeogeographic conclusions, suggesting that during the Middle and Late Jurassic epochs Kutch had close sea connections with Central Arabia, Afghanistan and Rajasthan on the one hand and Somalia and Malagasy on the other.  相似文献   

8.
From the Late Bathonian sponge biofacies at Jumara Dome, Kachchh (western India) 11 species of ‘lithistid’, hexactinellinid and calcarean sponges are described. New taxa are the order Sigmatospirida, the genusJumarella, and the speciesJumarella astrorhiza, Mastosia rhytidodes, Radicispongia kraspedophora, andHexactinella prisca. The diverse sponge assemblage is associated with a rich fauna of epibenthic bivalves and brachiopods and formed meadows on fine-grained carbonate substrates. The sponge meadows grew on a carbonate ramp at the lower end of the photic zone, in quiet waters below storm wave base. The rate of sedimentation exceeded that of sponge production. This prevented the development of reef-like bodies. In contrast to Mesozoic sponge reefs, growth of the sponge meadows appears to have been confined to the regressive phases of small transgressive-regressive cycles.  相似文献   

9.
The results of a palynological analysis of the sedimentary sequence of Borehole RCH-151, Chuperbhita Coalfield, Rajmahal Basin, Bihar are presented here. The borehole penetrated the Rajmahal Formation (comprising two traps sandwiching an intertrappean bed), the thinly represented Dubrajpur Formation and in its lower part, the Coal Measures. The coal-bearing interval is associated with Scheuringipollenites barakarensis, Faunipollenites varius, Densipollenites indicus, Gondisporites raniganjensis and Densipollenites magnicorpus Assemblage Zones. The presence of these biostratigraphic units indicates correlation with the Barakar Formation (Early Permian) and the Barren Measures and Raniganj Formations (both Late Permian). This is the first record, in the Chuperbhita Coalfield, of Late Permian strata, which appear to represent a condensed sequence. Prior to the present study, the Permian succession was thought to have been associated entirely with the Barakar Formation. The overlying Dubrajpur Formation yielded a distinct spore-pollen assemblage (in association with the first report of dinoflagellate, Phallocysta), which is assigned to the newly identified Callialasporites turbatus palynozone of latest Early to early Middle Jurassic age. The diverse spore-pollen flora of the intertrappean bed (Rajmahal Formation) incorporates several age marker taxa, viz. Undulatisporites, Leptolepidites, Klukisporites, Ruffordiaspora, and Coptospora. The assemblages from intertrappean beds are correlated with the Ruffordiaspora australiensis palynozone of Australia. Thus the palynodating indicates Permian, latest Early to early Mid-Jurassic and Early Cretaceous age for the strata studied. This is the first record of definite Jurassic microfossils from the non-marine sequence of Rajmahal Basin, India.  相似文献   

10.
Diversity of vascular plants was studied in three sacred groves of the Jaintia Hills, in northeast India. About 395 species, 250 genera, and 108 families comprising pteridophytes, gymnosperms and angiosperms were found in the groves. Orchidaceae, Rubiaceae, Asteraceae and Lauraceae were dominant families and Ficus was the largest genus, with nine species. About 160 tree species were distributed in canopy, subcanopy and under canopy strata of the forest. Concentration of tropical and temperate elements of the neighbouring Sino-Himalayan and Burma-Malayan regions, and endemic (54 species), rare (31 species) and primitive taxa (38 species) due to favourable climatic conditions and prolonged protection have contributed to the high species richness of the groves. Their better management and protection is important for the conservation of plant diversity in the region and also for the benefit of indigenous tribes of the state.  相似文献   

11.
Two specimens of the Middle Jurassic ammonite genusReineckeia (sensu lato) have been found in the lowest beds of the Pachchham (Patcham) Limestones exposed in the core of the Jumara Dome, Kachchh (Kutch), Gujarat, western India. The stratigraphy is described in detail and the age bracketed to lie between latest Late Bathonian and Middle Bathonian, older than any previously described examples of this genus, either in India or in Europe (middle Early Callovian). The new finds are compared with other known pre-Callovian Reineckeiidae, notably those of the eastern borders of the Pacific, but the relationships are not close. The phylogenetic consequences are briefly discussed. The roots of the Reineckeiidae continue to lie hidden.  相似文献   

12.
Six bivalve taxa belonging to the genusNeocrassina Fischer have been described from Middle Bathonian (Middle Jurassic) rocks of Kachchh, Western India. Of these,Neocrassina (N.) ovata (Smith), TV.(N.) robusta (Etallon) andN. (N.) paphia (d?Orbigny) have been recorded previously from various parts of Europe, whileNeocrassina (N.) pandeyi Maithani is an endemic faunal element as areNeocrassina (N.) sp. A andNeocrassina (N.) sp. B. The generic and sub-generic characters ofNeocrassina are reviewed as are affinities of the taxa with closely related forms from India and other parts of the world.  相似文献   

13.
The nutritional status of preschool children of the three sects of the Pahariya tribe (Rajmahal Hills, Bihar) was studied with the help of anthropometric indices like weight for age, height for age, weight for height und nutritional deficiency signs. The correlation between age and nutritional indices showed that the relationship was significant for % expected weight for age in the male children of all the three sects; r = +0.70 in Saurias, r = +0.32 in Mals and r = -0.72 in Kumarbhags (p > 0.01). Significant relationships were also observed in the correlations between weight for height in both sexes. Based on height for age and weight/height2 (Body Mass Index, BMI), 89% of the children of the Saurias, 92% of the Mals and 93% of the Kumarbhags were malnourished. Height for age of 50% of the children of the Pahariyas were below the 3rd percentile or below 90% of the Harvard standard. Chronic and current severe forms of malnutrition (i.e. height for age below 3rd percentile of standard and BMI 13.5) was highest in the Kumarbhags (17.5%). According to the modified Waterlow's classification chronic and current severe forms of malnutrition (i.e. height for age below 3rd percentile of the National Centre for Health Statistics, NCHS, and weight for height less than 80% of the standard) was highest in the Saurias (21.6%) and least in the Kumarbhags (15.4%). Kwashiorkor and marasmus for all the children of the Pahariyas ranged between 0.5-1.4% and 1.5-5.2%, respectively. Associated with signs of Protein Caloric Malnutrition (PCM), like moon face, dyspigmentation, sparseness and easy pluckability were more prevalent in all the three sects of the Pahariyas. Ocular manifestation of vitamin-A deficiency like conjunctiva xerosis and Bitos' spots were also frequent among these children.  相似文献   

14.
The Middle Jurassic flora from Stonesfield, Oxfordshire, UK   总被引:1,自引:0,他引:1  
The Stonesfield 'Slate' of Oxfordshire has yielded a diverse Middle Jurassic flora, containing 25 morphospecies, dominated by remains of araucariacean and cheirolepidiacean conifers, bennettitaleans, and leaves of the possible gymnosperm Pelourdea . It mainly represents coastal vegetation, which included mangrove-like stands of Ptilophyllum , and conifers probably growing in lowland coastal habitats that were subjected to periodic water-stress. The Pelourdea leaves may have drifted in from drier, more upland habitats. The flora is similar, but not identical to, the slightly older floras from the Cotswold 'Slate' of Gloucestershire, such as from Eyeford and Sevenhampton. Also comparable are the contemporaneous floras preserved in marine deposits in France and the Venetian Alps of Italy. It is quite different from the Middle Jurassic flora of Yorkshire, which is thought to represent vegetation growing in deltaic habitats. The new combinations Ptilophyllum pectiniformis (Sternberg), Komlopteris speciosa (Ettingshausen) and Pachypteris macrophylla (Brongniart) are proposed for species found at Stonesfield. Nilssoniopteris solitarium (Phillips) comb. nov. is proposed for the species previously named Nilssoniopteris vittata (Brongniart). Taeniopteris vittata Brongniart is retained as the type species of Taeniopteris , a morphogenus to be used for entire cycadophyte leaves that cannot be definitely assigned to the cycads or bennettitaleans. Conites is shown to be an earlier nomenclatural synonym of Bucklandia , to be used for casts and compressions of cycadophyte stems. This requires a number of new combinations for species that have hitherto been included in Bucklandia : Conites anomala (Stokes and Webb), C. gigas (Seward), C. indica (Seward), C. milleriana (Carruthers), C. pustulosa (Harris) and C. yatesii (Carruthers).  相似文献   

15.
The geographic origins and distributional patterns of Gondwanan teleosauroids during the Jurassic have been fiercely debated over many years. Unlike the rich thalattosuchian fossil record from Laurasia, teleosauroids described from Gondwanan ecosystems are relatively scarce. Most of the known occurrences consist of isolated and fragmentary bones collected in Madagascar, Morocco, Tunisia, India, and Ethiopia. Nevertheless, these specimens, although fragmentary, have provided substantial information for assessing the evolutionary scenarios of multiple teleosauroid lineages and have shown that certain teleosauroid taxa were widespread rather than endemic to Western Europe. Here, a partial skeleton of a teleosauroid crocodylomorph is described. It was found in the late Middle Jurassic (Callovian) deposits of southeastern Tunisia by a team of French and Tunisian paleontologists; however, it has not been thoroughly studied at both macro- and microscopic scale until now. The new specimen is composed of an incomplete symphyseal portion of a lower jaw in addition to isolated teeth, osteoderms (both dorsal and ventral), thoracic and caudal vertebrae, and several thoracic ribs. The specimen has several morphological characters that are reminiscent of longirostrine teleosauroids. Due to the total absence of other cranial bones, as well as the pectoral and pelvic girdles, the specimen is not diagnostic to the generic level. However, these new remains represent the youngest ascertained occurrence of a definitive non-machimosaurin teleosauroid in Africa, provide additional insights into the geographic distribution of Thalattosuchia, and raise once again the question whether the origins of this clade were Gondwanan or Laurasian.  相似文献   

16.
17.
18.
Bedi  S. J. 《Economic botany》1978,32(3):278-284
Economic Botany - This paper deals with the plants used by aboriginal tribes of Ratan Mahal and surrounding hills. Some of the important food and medicinal plants restricted to these tribes or this...  相似文献   

19.
Middle Jurassic calcareous algae from the circum-Arabian area   总被引:1,自引:0,他引:1  
Dr. Jochen Kuss 《Facies》1990,22(1):59-85
  相似文献   

20.
Silicified coniferous wood was collected from the Lanqi Formation (late Middle Jurassic in age) at Shebudaigou Village, Liaoning Province, China. Three taxa are identified, namely Pinoxylon dacotense Knowlton, Xenoxylon phyllocladoides Gothan, and Araucariopitys sp. Based on these new data, and those of other fossil plants reported previously from the same formation, we consider the climate during the deposition of the Lanqi Formation was subtropical, humid and seasonal. In this respect the Lanqi flora differs from the coeval Shimengou and Longmen floras from North China. The Longmen flora was deposited during more humid, subtropical conditions, while the Shimengou Formation indicates that the climate was warm temperate and dry. Our data would suggest that the Late Jurassic climatic pattern was initiated as early as the late Middle Jurassic.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号