This unit concordantly underlies the Yucunuti Formation (Middle Callovian), constituted by ~118 m of fine-grained sandstone, coquina and biomicrite
that bear pelecypods and gastropods; it is interpreted as a transitional to shallow neritic deposit.
The textural type recognized in this microfacies is wacke-packstone fabric according to Dunham (1962) and poorly- washed biomicrite according to Folk (1959).
The allochemical constituents are exclusively skeletal fragments displaying Wacke- Packstone depositional fabric according to Dunham (1962) and poorly washed biomicrite according to Folk (1959).
is the most characteristic lithol ogy of this facies, showing intense and well developed bacterial and cyanobacterial laminar textures coating the plant remains (Hernandez et al.
The fossil specimens were collected from a glauconitic biomicrite bed exposed in the North Sulphur River channel in Fannin County.
3 meter thick bed of glauconitic biomicrite is very fossiliferous and contains both reddish, ironstone casts and black, phosphatic casts and molds.
The topmost part of the upper Ballysteen Limestone contains lenses of Waulsortian biomicrite with associated calcarenites and argillites and two tuff horizons also occur.
These are veines bleues, stylonodular, wavy laminated, biomicrite dominated and transition unit.
is the most characteristic lithology of this facies, showing intense and well developed bacterial and cyanobacterial laminar textures coating the plant remains (Hernandez et al.
The Roxton Limestone is unusual among carbonates, being a fragmental glauconitic biomicrite
with large fragments (indicative of a high energy environment) within a micritic matrix (typical of a low energy situation).
In thin section the rocks from either side of the volcanogenic layer are sparse foraminiferal biomicrites
with heterohelicids as the dominant group.