Chesil beach joins the mainland to the Isle of Portland – that’s a landform called a tombolo i.e.) when an island is joined to the land by the deposition of beach sediment.
“It is one of three major coarse clastic (shingle/gravel) structures on the British coast and is unique in being a linear barrier beach whilst the others (Dungeness and Orford Ness) exhibit cuspate development.”
And there is much more of this intelligent stuff here: