. Bulletin of the British Museum (Natural History). 96 H. M. C. DANIELLI [= Argirvanellum Rothpletz, 1916; Batinevia Korde, 1966; Bolomlnella Reitlinger, 1959; Fisliilella Korde, 1973; Kenella Korde, 1973; Nicholsonia Korde, 1973; Siphonema Bornemann, 1886; Slrephochenis See\y, lUS; Slromatocerium MiUer, 1882], Range. Upper Proterozoic to Middle Cretaceous. Diagnosis. Microscopic tubular encrustations and/or impregnations of sheaths of fila- mentous organisms; filaments arranged at random or prostrate, rarely vertically; filaments single or in growths of variable size, shape and density; orien
. Bulletin of the British Museum (Natural History). 96 H. M. C. DANIELLI [= Argirvanellum Rothpletz, 1916; Batinevia Korde, 1966; Bolomlnella Reitlinger, 1959; Fisliilella Korde, 1973; Kenella Korde, 1973; Nicholsonia Korde, 1973; Siphonema Bornemann, 1886; Slrephochenis See\y, lUS; Slromatocerium MiUer, 1882], Range. Upper Proterozoic to Middle Cretaceous. Diagnosis. Microscopic tubular encrustations and/or impregnations of sheaths of fila- mentous organisms; filaments arranged at random or prostrate, rarely vertically; filaments single or in growths of variable size, shape and density; orientation parallel to random; filaments unbranched and slightly to highly sinuous; cell space approximately circular in cross section, sometimes compressed or with slight irregularities; cell space usually occupied by cement spar but sometimes micritic, cement developing either by growth from grains in the micritic tube or independently, as druses or equidimensional particles; aseptate micritic calcite tube comprising prisms or equidimensional grains, or both, the prisms with their long axes arranged perpendicularly to the filament axis and in a single layer, sometimes with smaller intercalated prisms. Neotype. The specimen shown on Fig. 5, after Wood (1957). Thin section kept by the Palaeontology Dept. of the British Museum (Natural History), London, reg. no. V 34566. Horizon and locality. Stinchar Limestone (Ordovician, Lower Caradocian Series), Tormitchell Quarry nearGirvan, Ayrshire, Scotland. Specific subdivision As Wood (1957) found, specific subdivision of Girvanella is a difficult problem. He drew a graph of internal diameters and obtained a bimodal curve for the sample he took from the. 13 15 17 19 21 23 Class intervals, pi Fig. 6 Internal diameters of Girvanella tubes from the Stinchar Limestone. Plain line, Aldons Quarry (Danielli herein, n=1060). Pecked line, Benan Burn and Tormitchell Quarry (after Wood 1957, with permission; n = 633).. Please note that these images a
Size: 1746px × 1432px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorbritishmuseumnaturalhistory, bookcentury1900, bookcoll
