Phyllolepida which means leaf scale were flattened, armoured fish with toothed jaw bones. They are readily distinguished by their flat armour made up of a single large plate on the top of the head and trunk rimmed by a regular series of smaller plates. The characteristic feature is that each plate has a radiating pattern of raised fine ridges and tubercles. Phyllolepids were probably blind as they lacked bones circling the eyes and the head shield is not embayed for the eyes. They had well-developed radiating patterns of sensory-time canals which may have helped them detect prey swimming above them while they were concealed below the surface under a fine layer of sediment. The largest of these fish were 50 to 60 cm in length.