"Witch's Hat"

Today I went into town to get my hair done. Whilst walking through the city centre, I glanced up at the upper part of the Waterside Shopping centre! Can't believe I'd not noticed this older part of the building before. I'm guessing this bit is a listed building!

Don't know what it is, but every time I go to the hairdressers' it rains and blows a gale when I go home afterwards. Today was no exception!!