@ta5172,
It appears to be sandstone however not being able to feel the texture that is just a guess. The holes are made by running water. This outcropping has risen and broken through to the surface by the wearing away of the topsoil. It could be a sedimentary lake bottom however without latitude and longitude it's impossible to know if this site was once covered by water in the distance past-in geological time that is. On second glance it appears to be bedrock limestone covered by moss and forced to the surface by tectonic forces. It's easy to test for the calcite and aragonite as they are the building blocks for limestone. As far as Tectonic forces are concerned this is the point it starts to get deep-and supposition replaces fact.
Like so many other things Tectonic movement is poorly understood by humans.