AS schoolchildren begin their summer holidays, many will have visited the Naze as part of their National Curriculum GCSE studies to complete fieldwork.

They come from all over Essex and east London to explore and study the unique geology of the cliffs and examine the impact coastal erosion is having.

What they learn is that 50 million years ago southern England had a sub-tropical climate and where we are now was submerged beneath a warm sea 100 metres deep.

Rivers flowed into this sea laying down mud and silt which over time compacted to form what is known as London clay, the blue-grey slippery deposit exposed at low tide.

The sea then was teeming with crocodiles, turtles, gastropods and sharks.

About three million years ago at the end of the Pliocene period, the whole of Essex began to be covered by the sea and as this process continued, layers of sand containing marine shells were laid down as dunes on the sea bed.

These shell dunes or banks are what we know today as the Red Crag. At the Naze this layer rests on the London clay. The red colour is due to the former presence of iron pyrite in the London clay where it oxidised.

When it rains the sandy texture of the Red Crag means it slumps and slides along the London Clay onto the beach where fossil shells such as the common dog cockle can easily be spotted, as well as sharks' teeth. The layer between the London clay and Red Crag also yields fossil whale bones and large land animals such as deer, wooly mammoth and elephant. These were washed into the Red Crag sea from Miocene deposits removed long ago and probably recycled many times before being incorporated into the Red Crag.

If you would like to help keep the Naze tidy then Essex Wildlife Trust has organised litter picks and welcome volunteers to lend a hand.

They are on July 26, August 9 and 30, and September 27 starting from the Naze Centre at 2pm (depending on weather conditions). Please bring your own gloves, but all other equipment is provided.

Lots of fun and educational activities have been organised for the school summer holidays, including a spectacular kite display and workshop on July 22 and 23 July. For details and booking call: 01255 679379 or visit