Thin section image through a rudist shell (Barrettia?). Found in the Upper Maastrichtian near Sta Theresa, southern Belize.
The cycles visible in the shell could be attributed to seasonal, lunar, tidal cycles?

Imprint of a nerineid gastropod.
Barton Creek dolomite, Albion island quarry in the Rio Negro, the border river between Belize and Quintana Roo Mexico. These gastropods are assumed to be exclusively of Jurassic-Cretaceous age

Lump of smectite with abundant vesicles, embedde in a conglomeratic debris-flow, containing abundant bioclast, a.o. rudistsSanta Theresa, southern Belize from a road-cut in the jungle. The roadcut is located in a graben, filled with debris from the surrounding highs, which are like end-Cretaceous times, composed of rudist bearing platform limestones
 

Such green-yellow vesicular fragments, composed of smectite are a typical feature of the Chicxulub impact ejecta that occur within a radius of 3000 km around the crater (map).