Bay Window - What is this called and what is its purpose?

[Gimpymoo]

Not my house, too lazy to take a photo but what is the bit atop of the bay window called?

Is it just for decoration or does it have a purpose?

Ours is looking in a sorry state, the elements have took their tole and it needs to be replaced/repaired?

What is it, plaster/masonary?

Thanks for any input.

 

[Gimpymoo]

Thanks for the replies.

We have had guttering all the way round since we moved in.

Will look at getting it re-rendered. I like to keep period features where practical but not sure if this makes a big difference?

All the other houses near mine have had them removed