... by Sardeson (1929) , who showed “ Rafinesquina ” minnesotaensis (probably Oepikina minnesotaensis ; see Pope, 1982 ) in a similar escape position to that seen in Sowerbyella . Evidence of movement also comes from traces associated with the widespread Cincinnatian brachiopod Rafinesquina alternata...

.... If plectambonitoids could have moved by clapping their valves, then the same may have been true of strophomenoids, such as Rafinesquina alternata . The ability to move sediment and adjust position explains how strophomenids could live in a convex-up position or even, if partially buried, in more vertical positions...

..., and gastropods, suggests a smothered life assemblage from soft bottom shallow marine platform conditions. The edrioasteroids settled on overturned shells of Rafinesquina alternata and on local hard surfaces provided by previously formed internal moulds of molluscs. Les édrioastéroïdes Isorophusella...

..., 1972 ; Alexander, 1975 ). The tendency of dead strophomenid shells to passively reorient was supported by experimental studies by Alexander (1975 ) and Savarese (1994 ). Alexander (1975 ) placed weighted plaster models of Rafinesquina alternata in a flume with a fine sand bottom. Five shape...

... it 2 30 100 Fine-grained light gray limestone. Some beds porous from weathering. Beds even and 2–4 inches thick. Plectambonites sericeus (Sowerby), Rafinesquina alternata (Emmons), Rhynchotrema increbescens Hall 3 125 225 Fine-grained gray limestone for most part but more crystalline...

...Figure 1. Distributions of strophomenide outline length (SOL) for four Liberty species. Species distributions, from left to right, represent Eochonetes (Thaerodonta) clarksvillensis , Leptaena richmondensis , Strophomena planumbona , and Rafinesquina alternata , respectively (brachiopods...

...Figure 2 —Socket plates and pads. Detail of transverse serial sections of the dorsal valve showing cardinal process and socket. All scale bars are 1 mm. 1 , Nasutimena fluctuosa , GSC 113842. 2 , Strophomena planumbona , GSC 113845. 3 , Coolinia gamachiana , GSC 113858. 4 , Rafinesquina...

... ulrichi r U Bucania hall Crania sp. new Lophospira perangulata r Crania granulosa U Eccyliopterus vagrans L Pholidops trentonensis r U Eccyliomphalus proclivis r L Rafinesquina alternata Pterotheca attenuata Rafinesquina minnesotensis r Orthoceras lesueuri U...

... <: paf~I~.nl I,~ ollondleo ~ ~, of £.d~ £ ponuloetormlS ~hsphaer~ sP, LOII~ 'p. Siau rocephal,les sp Anlsocerosl'e~ .p Eu n'c"es s p ~sp. Kellnero'es sp ~.p, Poroqlyclfl'e p Olopotr~ 5p ' . .-L. . Grey '0 pIn kIln Col c orlou, sand.tont and Quartz;' I WIt h bands at Llrnnlane RAFINESQUINA ALTERNATA CE NOZONE RQfll'lU9UinQ ·~o. Satfordlo ,p I Monotrypa ,p, Strophoml no ~p Figure 2, Not known and melanosclerites have also been found. A check list of the ~flora is given later. Phytostratigraphy Only one phytostratigraphic unit, i.e., Co/as/ylis zone can provisionally be recog- nized within the formation. Age Faunal and floral evidences clearly indicate an Upper Ordovician-Lower Silurian (Caradocian to Llandoverian) age to the Yong Limestone. Chiti nozo a-Sc 01 ecodonts assembIage A poorly preserved palynological assemblage comprising of chitinozoa and 8CO- lecodonts has been recorded from the Yong Limestone horizon of Kurnaun Tethys Himalaya (Sinha, 1982). The assemblage 'is neither rich in quantity nor in species. ASHOK K. KHANNA AND OTHERS 195 differentiation. Chitinozoa are represented by 10 species assignable to 4 genera and scolecodonts by 9 taxa. Besides, a solitary specimen of acritarch genus, Baltisphaeridium has also been encountered in the assemblage. Chitinozoa and scolecodonts are black and opaque. The state of palynofossils varies even "Yithin one species and from sample to sample. Transparent forms have not been recorded at all. No mutual relationship between the abundance of chitinozoa, scolecodonts and acritarchs within the same sample or group of samples has been observed. Out of 9 samples collected, 4 have yielded palynofossils. A check list of the palynomorphs is given below. Taxa listed here are in alphabetical order without attempting to accommodate them in any of the taxonomic system presently in existence (Plate 1). CHITINOZOA Form Genus Form Genus Form Genus Form Genus Conochitina C. brevis C. brevisconica C. cf. dactylis C. cf. latifrons C, parviventer C. proboscifera Cyathoclzitina C. campanulaeformis Eisenackitina E. oelandica Lagenochitina L. brevicollis L. e/egans L. sp. SCOLECODONTS Form Genus Anisocerasites Arabellites Arites Diopafraites Eunicites Kettnerites Oenonites Paraglycerites Staurocephalites STRATIGRAPHIC SIGNIFICANCE OF PALYNOMORPHS Chitinozoa and scolecodonts constitute the palynological assemblage of Yong Limestone. Chitinozoa species are more reliable stratigraphic indices, and hence have been used as palynological datum markers in the determination of age of the Yong Limestone and delineation of Ordo-Silurian boundary in Kumaun Tethys Himalaya. Global repartition of chitinozoan taxa encountered in the present palyno-assemblage indicates that out of ten chitinozoan species 6 range from Ordovician to Silurian (Fig. 3) thereby indicating Ordo-Silurian affinity of the palynomorphs. The stratigraphic horizon (Shia)a Formation) lying below Yong Limestone 3 196 YONG LIMESTONE OF TETHYS HIMALAYA STRATIGRAPHIC RANGE CONOCHITINA PARVIVEN TER -~ ~~ -~Ui.ACKITINA OE LANDICA LAGENOCHITINA BREVICOLUS CONOCHI TINA DACTYLI~ ~ CONOCHlTINA PR080SCI FE RA e ONOCH ITINA LATIFRONS CYATHOCHITINA CAM PANULAEFORM IS r-- lAGE NOCHlTI NA EL EGA NS CONQCHITINA BREVIS CONDe HIT INA BRE VIS CON leA z z zz oCt z g .zz 5:C2z z >S 0 oCt ~ «W Q: r ~ ~ Z It: t!l > 4J Rafinesquina alternata with other metazoan fossils and is of definite upper Ordovician age. The Yong Limestone mainly contains...