Pangaea began to break up at the start of the Jurassic period. Sea levels rose and Britain drifted on the Eurasian Plate to between 31° and 40° north. Much of Britain was under water again, and sedimentary rocks were deposited and can now be found underlying much of England from the Cleveland Hills of Yorkshire to the Jurassic Coast in Dorset. These include sandstones, greensands, oolitic limestone of the Cotswold Hills, corallian limestone of the Vale of White Horse and the Isle of Portland. The burial of algae and bacteria below the mud of the sea floor during this time resulted in the formation of North Sea oil and natural gas