The extinct Coniasaurus is a marine squamate, from the largest order of reptiles of the Late Cretaceous period, which have been described from chalk deposits (from the Upper Cretaceous limestone of the era) and incomplete specimens.
Coniasaurus is an extinct genus of Late Cretaceous marine squamates that range in age from Cenomanian to Santonian. It was first described by Richard Owens in 1850 from lower Cenomanian chalk deposits in southeast England. Coniasaurus has only been described from incomplete specimens, but it is known to have had a relatively elongate skull with specialised teeth. The Cretaceous is named after the white limestone known as chalk which occurs widely in northern France and is seen in the white cliffs of south-eastern England, and which dates from this time. Order: Squamata Squamata (/skwmet/, Latin squamatus ("scaly, having scales")) is the largest order of reptiles, comprising lizards, snakes and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. 
