Many thanks @WalterEgo, that makes a huge difference. I am sure those are from an Eastern Grey Kangaroo. I have collected hundreds of thousands of them so I am reasonably familiar with them. Wombat droppings are larger and more cubic in shape. And often wombat droppings have less of the dark crust on the outside, i.e. more similar inside and outside. Breaking one of them open was a good idea because something that sets the droppings of those two species apart, and Red Necked Wallabies, is that their droppings are composed exclusively of finely chewed grass. The dung of Black (Swamp) Wallabies, and Feral Pigs contain coarser fragments.