It chiefly consists of stratified volcanic tuffs rich in coal, lignite, fossilized plants and an invertebrate fauna.
Like the woodlice they were capable of rolling themselves up into a ball, many specimens having been found fossilized in this state, with the pygidium pressed tightly against the head-shield.
There seems to be no doubt that fossilized remains of the dingo occur intermingled with those of the extinct Australian mammals, such as giant kangaroos, giant wombats and the still more gigantic Diprotodon.
In times of drought these animals undoubtedly resorted to the same water-courses for drink, and thus their fossilized remains are found associated.
It marks the relations which subsist between all members of the plant world, including those between existing groups and those which are known only from their fossilized remains preserved in the rocks.