Ice lens

I saw this thick ice circle on our walk yesterday morning. It was on the grass verge next to a bowl of water which is usually there for dogs who are out walking with their owners. 
It had been removed in order for the pampered pooches to take a drink of necessary. 
There were not many people, or dogs to be seen at the time.
Glorious sharp light of a sparkly February day. Crystal clear blue skies.