Original: Evidence of original colouration has been detected in cephalopod fossils dating as far back as the Silurian; these orthoconic individuals bore concentric stripes, which are thought to have served as camouflage.
Simplified: Evidence of original colouration has been found in cephalopod fossils as far back as the Silurian; certain straight-shelled species had lines round their shell, which are thought to have used as camouflage of their body outline.