black stuff on plants :(

Hi guys,

I've got some black circles/ovals stuck to the undersides of a leaf. I also have black sticky spots on the top surface of some leaves. I'm not sure if the black circles are pests or something they leave behind. Any one know what they are and to the get rid of them ?

Cheers

Do you have any other pics? Is there any damage to the leaves?

looks like poop