The following descriptions are in no way intended to be comprehensive and are intended only as a guide to what is displayed in the images. Extra information is available on the annotated images.
Thalassinoides The name of the mottles which give the Tyndall Stone its distinctive appearance. The mottles are actually fossils. They are traces of burrows made in the original sediment by an unknown animal and the disturbed sediment within the burrows has been preferentially dolomitised at a later date making it darker and more resistant to weathering. Because Thalassinoides is always present and usually abundant it is not always indicated. Smaller burrows tentatively attributed to Annelid worms can often be distinguished inside the larger traces.
Trypanites is the name given to the holes left behind when a hard substance is bored into by an organism.
Tabulate and Rugose corals were ancient types not related to modern corals. They are now extinct.
Catenipora was a colonial tabulate coral. Individual corallites which form the colony grew as a vertical tube with elliptical cross-section and joined along the edges to give the appearance of a chain, hence the common name Chain Coral.
Saffordophyllum was a colonial tabulate coral in which the vertical tubes of the corallites are polygonal in cross-section and joined on all sides to give the appearance of a honeycomb, hence the common name Honeycomb Coral.
Calapoecia was a colonial tabulate coral in which the vertical tubes of the corallites are separated from each other by a calcareous mesh.
Chaetetes was a colonial tabulate coral in which the vertical tubes of the closely packed corallites are polygonal in cross-section but are extremely small.
Protrochiscolithus was a colonial tabulate coral with little obvious structure and is seen as a white crust growing on other fossils.
Grewingkia was a solitary rugose coral. Individuals were separate and grew in the shape of a slightly curved cone rather like a cow's horn, hence the common name Horn Coral. In cross-section the fossil shows a circular to elliptical shape with septa radiating from the centre. In vertical section it shows an elongated curved triangular shape with septa running along its length.
Palaeophyllum was a colonial rugose coral which shows loosely joined cylindrical corallites with septa.
Stromatoporoids were colonial animals in which the very small individuals formed layers as the colony grew. They are now extinct.
Cystostroma shows grey growth layers and an encrusting habit.
Receptaculitids were animals with a similar life style to modern sponges. They are now extinct.
Fisherites was a large form which grew in the shape of a hollow irregular sphere, the walls of which were double and made up of small hexagonal plates and rods. In some sections the arrangement of the plates resembles a sunflower blossom hence the common, but erroneous name, Sunflower Coral.