This succession includes dark grey shales of the Sembar Formation, hemi pelagic nodular limestones, marls and shales of the Goru Formation (Shah, 1977) and biomicrite
sand marls of the Parh Limestone.
Allochems were bioclasts (foraminifera test and microshell fragments) embedded in a fine-grained calcite matrix (foram biomicrite
; Figures 2b, c).
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., 1998).
The fossil specimens were collected from a glauconitic biomicrite
bed exposed in the North Sulphur River channel in Fannin County.
The topmost part of the upper Ballysteen Limestone contains lenses of Waulsortian biomicrite
with associated calcarenites and argillites and two tuff horizons also occur.
The textural type recognized in this microfacies is wacke-packstone fabric according to Dunham (1962) and poorly- washed biomicrite
according to Folk (1959).
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., 1998).
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).
The samples from La Luna Formation (Turonian-Coniacian) were taken from Quebrada La Sorda, Santander, where they are characterized by the dominance of foraminifera biomicrites
with partial silicification, pseudospar and siliciclastic sediments of silt and sand sizes, mainly towards the top of the unit (Sarmiento et al.
In thin section the rocks from either side of the volcanogenic layer are sparse foraminiferal biomicrites
with heterohelicids as the dominant group.