Sand tits form attached to an ironstone biscuit band. The biscuit band is a seam of ironstone  laying in the sandstone and clay levels. The ironstone sometimes has opal lines and pools within it.
The brown ferruginous sandstone formations look like little miniature stalactites hanging from an ironstone biscuit band in clay. The sand tits’ ironstone has a more sandy consistency than do the  hard ironstone nuts. And the tits have a yellow ochre, thin limonite colored exterior skin. There can be more horizontal lines of opal in a tit besides at the join to the ironstone band. One theory is that this formation is the result of annelids that are little wormlike, segmented creatures that bored into the clay bed of ancient sandy sea floors. Most must be contour cut with a dremil tool in order to cut into stones.