Beneath the waterline.

gastornis:

The Bluntnose sixgill shark, or cow shark (Hexanchus griseus), is a very large (18ft) cartilaginous fish in the order Hexanchiformes. This strange order of sharks consists of the most primitive types, including many fossil species. 

The closest living relatives of the sixgill include the dogfish and the Greenland shark, but it is suggested that this species has closer relatives in the fossil record.

An apex predator, the sixgill inhabits very deep waters, generally remaining under a depth of 300 feet, feeding on organisms such as other sharks, rays, chimaeras, bony fish, squids, carrion, and sometimes seals.