A small irregularly shaped chunk of white flint shows one surface covered in tiny spherical bodies linked together by thread-like structures. These are silicified infillings of a once open network within hard calcareous shell material. The spherical chambers housed sponge tissues that were laterally interlinked and connected to the surrounding sea water by vertical canals. The original shell material has been dissolved away and the hidden network of borings revealed in relief. The specimen has been mounted on a thick glass plate that was formerly featured in a display case at the Royal Ontario Museum. A scale bar is graduated in millimetres.
A close-up of the silicified network of borings showing the infilled chambers and connecting canals.
Staying with a #trace #fossil theme on #SpongeThursday! Entobia cretacea is the name given to these silicified casts of clionaid sponge #borings in a hard calcareous substrate (now dissolved) -- spherical chambers were connected by a network of canals -- scale bar in mm #Cretaceous (~85 MYA) Kent UK
