Palynofloral investigation of the kopili formation (late eocene) exposed near Umrongso in North Cachar Hills District, Assam, India

Abstract

The palynoflora recovered from the Kopili Formation (Late Eocene) exposed al 8'5 km south-east of Umrongso on Umrongso-Haflong Road, North Cachar Hills. Assam. India is described here. The pteridophytic spores, represenled by Cyathidites, Striatriletes, Todisporites, Polypodiaceaesporites. Lygodiumsporites, Polypodiisporites, etc., constitute the major part (60%) of the assemblage whereas gymnospermous pollen are poorly represented. The angiospermous pollen (35%) are represented by Densiverrupollenites, Tricolporopollis, Retitricolporites etc. Dinoflagellate cysts and fungal remains have also been recorded. Reworked Permian and Triassic palynofossils Iike Indotriradites and Klausipollenites respectively are also met with. The palynoflora indicates that the area enjoyed a tropical-subtropical, warm-humid climate and that the deposition of the Kopili Formation took place in a coastal environment with heavy rainfall and sufficient fresh water influx.

Calamitean Cones and Their In Situ Spores from the Pennsylvanian Limnic Basins of the Czech Republic

“…Seventeen species of genera, such as the Calamocarpon Baxter, Calamostachys , Mazostachys , Palaeostachya , Pendulostachys Good, Pothocites Paterson, and Weissistachys Rothwell & Taylor, yielded spores of the Elaterites type from mainly petrified ( Table 11 ) [ 9 , 21 ] and adpression [ 15 ] specimens. The size range of these microspores is 38 (78) 280 µm, and almost all of them are 38–112 µm in diameter, except for those isolated from Calamostachys americana Arnold, which is unusually large (140–280 µm) [ 10 ]. Some authors [ 10 , 12 , 34 ] propose that all calamiteans produced microspores of the Elaterites type.…”

“…The size range of these microspores is 38 (78) 280 µm, and almost all of them are 38–112 µm in diameter, except for those isolated from Calamostachys americana Arnold, which is unusually large (140–280 µm) [ 10 ]. Some authors [ 10 , 12 , 34 ] propose that all calamiteans produced microspores of the Elaterites type. We have studied hundreds of palynological slides with in situ Calamospora populations in different stages of ontogeny, macerated from sixty specimens of calamitean cones, and we have never seen any elaters or any elater-like structures or their fragments.…”

“…It is evident that there is a group of calamitean cones that produced spores of the Elaterites type, but the majority of them yielded only spores of the Calamospora type. Some authors [ 10 , 12 , 24 ] have proposed that Vestispora represents an ontogenetic stage of Calamospora . The authors of [ 35 ] excluded this theory based on some main points, and the authors confirmed their conclusions.…”

“…The genus was established [ 8 ] with the species type C. hartungiana Schopf et al The number of classification criteria is low [ 10 , 11 ]. These include the contact area, length of rays of the trilete mark, labrum, number, size, shape, position of the secondary folds of the exine, and diameter.…”

“…Other parent plants mainly include noeggerathialeans and certain sphenophyllaleans [ 7 ]. The relationship of Calamospora from Elaterites Wilson, Vestispora (Wilson & Hoffmeister) Wilson & Venkatachala, and some monopseudosaccate forms of the Remysporites / Auroraspora / Perotrilites type has been discussed [ 10 , 12 ]. This paper describes sixty-one specimens of four calamitean Calamospora -producing genera from the Kladno-Rakovník, Radnice, and the Czech part of the Intra-Sudetic basins of the Czech Republic.…”