Chalk: noun; ‘a white soft earthy limestone (calcium carbonate) formed from the skeletal remains of sea creatures’, according to the Oxford Dictionary, though that seems a relatively simplistic explanation to me. I chose chalk as this week’s word as I was in East Sussex last week and had occasion twice to see the magnificent chalk cliffs known as the Seven Sisters, once at Birling Gap in a howling gale and again, at Cuckmere Haven, on a day that felt like summer had come early to southern England.
The Discovering Fossils website has this to say about the chalk at the Seven Sisters:
The Chalk at Seven Sisters belongs to the Upper Chalk, and was deposited during the Coniacian and Santonian stages of the Late Cretaceous epoch between 87-84 million years ago (mya). At this time Seven Sisters and much of Great Britain, along with Europe, lay beneath a relatively shallow sea around 40°N of the equator, on an equivalent latitude to the Mediterranean Sea today.
And you can read more about the fascinating process of chalk formation here.